Contemporary diagnostic and therapeutic strategies for many solid tumors rely on understanding the Mismatch Repair (MMR) system, a fundamental DNA repair mechanism responsible for correcting errors introduced during DNA replication. Pathology reports written for tumors excised in surgery, often indicate the expression status of MMR proteins. This is of significant clinical value, as loss of MMR protein expression is associated with the accumulation of DNA replication errors. The MMR system recognizes and replaces mismatched nucleotides, particularly in microsatellite regions. These are short, repetitive non-coding DNA sequences prone to replication errors. When MMR proteins are inactivated by genetic or epigenetic alterations, MMR deficiency (dMMR) occurs, preventing repair and leading to microsatellite instability (MSI). MSI is a hallmark of Lynch syndrome, which is commonly associated with colorectal cancer (CRC) and endometrial cancer. This work highlights the clinical utility of MMR protein and MSI status as molecular signatures and discusses diagnostic, prognostic, and therapeutic implications. Understanding these molecular changes supports clinicians in making informed therapeutic decisions and may improve patient outcomes by providing personalized treatments to fit individual tumor profiles.

Lynch syndrome (LS) screening methods include multistep molecular somatic tumor testing to distinguish likely-LS patients from sporadic cases, which can be costly and complex. Also, direct germline testing for LS for every diagnosed solid cancer patient is a challenge in resource limited settings. We developed a unique machine learning scoring model to ascertain likely-LS cases from a cohort of colorectal cancer (CRC) patients.

We used CRC patients from the cBioPortal database (TCGA studies) with complete clinicopathologic and somatic genomics data. We determined the rate of pathogenic/likely pathogenic variants in five (5) LS genes (MLH1, MSH2, MSH6, PMS2, EPCAM), and the BRAF mutations using a pre-designed bioinformatic annotation pipeline. Annovar, Intervar, Variant Effect Predictor (VEP), and OncoKB software tools were used to functionally annotate and interpret somatic variants detected. The OncoKB precision oncology knowledge base was used to provide information on the effects of the identified variants. We scored the clinicopathologic and somatic genomics data automatically using a machine learning model to discriminate between likely-LS and sporadic CRC cases. The training and testing datasets comprised of 80% and 20% of the total CRC patients, respectively. Group regularisation methods in combination with 10-fold cross-validation were performed for feature selection on the training data.

Out of 4800 CRC patients frorm the TCGA datasets with clinicopathological and somatic genomics data, we ascertained 524 patients with complete data. The scoring model using both clinicopathological and genetic characteristics for likely-LS showed a sensitivity and specificity of 100%, and both had the maximum accuracy, area under the curve (AUC) and AUC for precision-recall (AUCPR) of 1. In a similar analysis, the training and testing models that only relied on clinical or pathological characteristics had a sensitivity of 0.88 and 0.50, specificity of 0.55 and 0.51, accuracy of 0.58 and 0.51, AUC of 0.74 and 0.61, and AUCPR of 0.21 and 0.19, respectively.

Simultaneous scoring of LS clinicopathological and somatic genomics data can improve prediction and ascertainment for likely-LS from all CRC cases. This approach can increase accuracy while reducing the reliance on expensive direct germline testing for all CRC patients, making LS screening more accessible and cost-effective, especially in resource-limited settings.

The genes NBN and MLH1 are critical for DNA repair, and this study aimed to detect and predict the effects of pathogenic single nucleotide polymorphisms (SNPs) in their mRNA and protein sequences. An in silico analysis assessed the impact of SNPs on the physicochemical properties, structure, stability, and function of MLH1 and NBN proteins. Results revealed that some SNPs significantly alter protein stability, structure, and binding interactions, potentially impairing DNA repair. Molecular docking studies further indicated disruptions in protein-protein interactions due to specific SNPs. These findings underscore the importance of using in silico methods to predict the functional effects of genetic variations, providing insights that could guide personalized treatments and improve cancer detection.

Hereditary colorectal cancer (CRC) syndromes account for up to 5% of CRC. Patients have an increased risk of CRC and extracolonic cancers, both of which develop at an early age. The main polyposis syndromes include familial adenomatous polyposis, MYH-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis syndrome, and PTEN hamartoma syndrome. The non-polyposis syndromes include Lynch syndrome and familial colorectal cancer type X. Each of the syndromes have distinct but sometimes overlapping phenotypes. Clinical evaluation and ultimately the underlying germline genetic pathogenic variants define the syndromes. Each syndrome has polyp, CRC, and extracolonic risks and management is based on early and timely surveillance with therapeutic and often extended prophylactic surgery. Surgical intervention strategies are individualized, considering not only the earlier onset of malignancies and heightened risks for metachronous cancers but also the patient's needs and quality of life. This article reviews the different diagnostic approaches to hereditary CRC and highlights subsequent disease-specific management and surgical decision-making strategies.

Lynch syndrome (LS)-also known as Hereditary Non-Polyposis Colorectal Cancer (HNPCC)-is caused by pathogenic germline mutations in DNA mismatch repair (MMR) genes such as MLH1, MSH2, MSH6, and PMS2. Although it accounts for only 1-5% of all colorectal cancers (CRCs), LS presents with a particularly high lifetime cancer risk and often occurs at younger ages. Identifying LS in patients under 60 years old is crucial for targeted surveillance and early interventions. Variations in clinical presentation and prognosis may exist based on the specific gene mutated, yet these patterns are not fully elucidated. This review aims to synthesize data on clinical outcomes among LS patients under 60, with an emphasis on how different MMR gene mutation patterns might influence prognosis, survival, and treatment decisions. Five population-based studies examining CRC patients younger than 60 years were included according to predefined eligibility criteria. Two independent reviewers screened and extracted data focusing on MMR deficiency detection methods (microsatellite instability [MSI] and/or immunohistochemistry [IHC]), rates of confirmed germline mutations, frequency of BRAF testing, and clinical endpoints such as stage distribution, survival outcomes, and recurrence. Risk of bias was assessed using standardized tools appropriate to each study design. The synthesis focused on comparing outcomes among individuals with MLH1, MSH2, MSH6, and PMS2 mutations, as well as delineating the proportion of patients with sporadic MSI under 60 years of age. Across the five studies, MSI positivity in CRC patients under 60 years ranged from 7.5% to 13%. The frequency of confirmed germline MMR mutations varied between 0.8% and 5.2% in specific cohorts, aligning with LS prevalence estimates of 1-5%. Different mutation patterns correlated with some variation in clinical presentation. Cases with MSH2 and MLH1 mutations more frequently exhibited synchronous or metachronous tumors, while MSH6 and PMS2 mutations displayed more heterogeneous IHC patterns. Where survival data were provided, LS patients under 60 years had better overall survival compared to MMR-proficient individuals, though some studies also noted a potential lack of benefit from standard 5-fluorouracil adjuvant therapy in MMR-deficient tumors. Screening by MSI or by IHC-supplemented with BRAF mutation testing to exclude sporadic MSI-facilitates early detection of LS in CRC patients under 60 and highlights notable differences between mutation types. Although overall outcomes for LS patients can be favorable, especially for stage II disease, the precise impact of each specific mutated gene on clinical course remains heterogeneous. Future large-scale prospective studies are needed to clarify optimal screening protocols and individualized treatment strategies for LS patients under 60.

Background: The efficacy of germline testing in colorectal cancer has been proven; however, germline testing in individuals with sebaceous neoplasms is less well defined. This review aims to summarize the literature on sebaceous neoplasms to date, describing the somatic tumor profiles, tumor screening methods, and personal and family history that are suspicious of a germline mutation. Sebaceous neoplasms can be attributed to a variety of etiologies, including UV exposure, immunodeficiency, germline mutations, or multifactorial influences associated with aging. Sebaceous tumors with abnormal microsatellite instability and mismatch repair deficiency are indicative of a germline mutation in 20-50% of cases, which is similar to rates found in colorectal tumors. Personal and familial history can also be suggestive of a germline etiology in these patients and should be assessed routinely, as approximately 30% of individuals with sebaceous neoplasms carry a germline mutation. We outline a strategy for the identification of individuals at risk for germline mutations, recommendations for the management of mutation carriers, and treatment options for individuals with sebaceous neoplasms. Conclusions: Sebaceous tumors are most often sporadic; however, evaluations of a germline etiology are prudent to effectively identify those at risk of additional malignancies as well as at-risk family members. Referral to genetic counseling and germline genetic testing for individuals at risk can significantly impact cancer treatment and screening in patients and their families.

The molecular classification of endometrial cancer (EC), as proposed by The Cancer Genome Atlas (TCGA), has transformed tumor classification, but there is a lack of extensive research on the molecular profiles and subtyping of endometrial cancer patients in China.

200 EC patients were classified into the following four molecular types: (i) POLEmut; (ii) MSI-H; (iii) TP53mut; (iv) NSMP. This study aimed to investigate the molecular characteristics of EC patients at a single center by large-scale next generation sequencing(NGS), including clinicopathological features and gene mutations in patients with distinct molecular types, and to assess the relevance of molecular subtyping for postoperative adjuvant therapy.

NSMP group was the most prevalent, comprising 46.0% (92/200) of cases, followed by the TP53mut group at 17.5% (35/200), the MSI-H group at 23.5% (47/200), and the POLEmut group at 13.0% (26/200). CTNNB1 mutations were common in the POLEmut group but rare in the TP53mut group. With the application of the new European Society for Medical Oncology (ESMO) 2022 classification, 27 patients (14.1%) were reclassified. Concordance between the two classifications regarding postoperative risk was observed in 85.9% (165/192) of cases. Seven patients (3.6%) were downstaged, and twenty patients (10.4%) were upgraded. Additionally, the analysis revealed that eleven genes were significantly mutated in patients with lymphovascular space invasion (LVSI) compared to those without LVSI. Notably, NSD3 and POLD1 were highly mutated in patients with lymphatic metastasis compared to those without lymphatic metastasis. Conclusively, large-scale NGS has revolutionized EC management by facilitating rapid molecular subtype identification, guiding tailored adjuvant therapies, targeted treatments, and immunotherapies, and efficiently screening for Lynch syndrome, thereby significantly improving patient outcomes.

Lynch syndrome is the most common hereditary cancer predisposition, accounting for 1-5% of colorectal cancer cases, and is driven by germline mutations in DNA mismatch repair genes. Despite established diagnostic criteria, such as the Amsterdam guidelines, Lynch syndrome remains largely underdiagnosed. To address this gap, universal tumour screening has been introduced for all newly diagnosed cases of colorectal cancer and endometrial cancer, significantly improving early detection. The surgical management of colorectal cancer in patients with Lynch syndrome remains controversial. While extended colectomy reduces the risk of metachronous colorectal cancer, surgical strategies must be carefully individualised based on patient-specific factors. Chemoprevention with aspirin has shown promise in reducing the risk of colorectal cancer, with ongoing trials investigating optimal dosing. Immunotherapy, particularly immune checkpoint inhibitors, has revolutionised the treatment of Microsatellite Instability-High/deficient Mismatch Repair colorectal cancer, offering durable responses and significant survival benefits. In addition, the neoadjuvant use of immune checkpoint inhibitors is paving the way for non-surgical interventions, potentially transforming the management of colorectal cancer in patients with Lynch syndrome. A multidisciplinary approach and continued research are essential to optimise cancer prevention, treatment and quality of life for people with Lynch syndrome.

To describe mismatch repair (MMR) and microsatellite instability (MSI) testing practices in laboratories using the College of American Pathologists (CAP) MSI/MMR proficiency testing programs prior to the 2022 publication of the MSI/MMR practice guidelines copublished by CAP and the Association of Molecular Pathology (AMP).

Data from supplemental questionnaires provided with the 2020-B MSI/MMR programs to 542 laboratories across different practice settings were reviewed. Questionnaires contained 21 questions regarding the type of testing performed, specimen/tumor types used for testing, and clinical practices for checkpoint blockade therapy.

Domestic laboratories test for MSI/MMR more often than international laboratories (P = .04) and academic hospitals/medical centers test more frequently than nonhospital sites/clinics (P = .03). The most commonly used testing modality is immunohistochemistry, followed by polymerase chain reaction, then next-generation sequencing. Most laboratories (72.6%; 347/478) reported awareness of the use of immune checkpoint inhibitor therapy for patients with high MSI or MMR-deficient results.

The results demonstrate the state of MMR and MSI testing in laboratories prior to the publication of the CAP/AMP best practice guidelines, highlighting differences between various laboratory types. The findings indicate the importance of consensus guidelines and provide a baseline for comparison after their implementation.

Signet-ring cell carcinoma (SRCC) is a rare subtype of colorectal cancer. The incidence of primary colonic SRCC is relatively rare in pediatric patients, with a limited number of reported cases currently available. The prognosis for this specific tumor type is unfavorable, and the preoperative diagnosis presents challenges, potentially leading to misdiagnosis. This case report describes the diagnosis of primary SRCC in the colon of a 10-year-old girl.

The patient was admitted to the hospital due to abdominal pain and vomiting. A computed tomography scan revealed an irregular mass with soft tissue density in her transverse colon, showing uneven density and multiple calcifications. The patient underwent surgical resection of the affected bowel and lymph node dissection, which was confirmed by pathological examination to be SRCC infiltrating both nerves and the entire intestinal wall. Additionally, tumor thrombus formation was observed in blood vessels and lymphatic vessels, multiple cancerous nodules were found in the omentum, and metastasis to 18 of 26 mesenteric lymph nodes examined. Immunohistochemistry for mismatch repair gene protein demonstrated microsatellite stability. No mutations in KRAS, NRAS, BRAF, or PIK3CA genes were detected through molecular pathology analysis. After surgery, she received standard chemotherapy for 8 cycles without tumor progression or other abnormalities during a 12-month follow-up period.

Primary colonic SRCC is a rare malignant tumor with atypical clinical symptoms, and timely identification and intervention are crucial for improving the prognosis.

Translating evidence-based practices into real-world healthcare settings is challenging, particularly in the rapidly evolving field of genomics. A pragmatic two-arm cluster-randomized clinical trial (Hide and Seek Project - HaSP) tested two implementation approaches for improving hereditary cancer referral practices with one key distinction: implementation strategies that were designed 1) explicitly using psychological theory, or 2) using healthcare professional intuition. This mixed-methods process evaluation aimed to provide insights into how and why change occurred by examining contextual determinants, identifying mechanisms of action, and exploring the role of theory.

Post-implementation interviews were conducted with Implementation Leads and clinicians from participating HaSP sites. Transcripts were analysed using a mixed inductive and deductive approach, guided by the updated Consolidated Framework for Implementation Research (2.0). Findings were triangulated with other HaSP process evaluation data sources, including HaSP focus group observations, HaSP research team focus groups, MDT observations, and Implementation Lead project logs. Logic models and case studies were developed to articulate causal processes underlying strategy effectiveness and conditions necessary for implementation success.

Eighteen participants from seven HaSP sites were interviewed. Qualitative analysis identified themes related to Lynch syndrome complexity, pandemic disruptions, operational challenges, information technology constraints, multidisciplinary collaboration, cultural determinants, attitudes towards change, the value of theory, adaptations, and implementation support. Within these themes, a total of 39 contextual determinants were identified, with barriers and facilitators spanning 18 CFIR constructs across five domains. Logic models and case studies highlighted a number of mechanisms of action, producing variable clinical outcomes. Process evaluation findings, interpreted together with HaSP trial outcomes, indicate that theory-based implementation strategies may better support Lynch syndrome detection practices compared to intuition-based strategies.

The information gained from this process evaluation deepens understanding of the factors influencing the success of hospital-specific implementation strategies within the HaSP framework. Potential pathways for optimising the effectiveness of the overall HaSP implementation approach have been identified.

Australian New Zealand Clinical Trials Registry, ACTRN12618001072202. Registered 27 June 2018, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375348&isReview=true .

Rapid and accurate identification of mismatch repair (MMR) deficiency and Lynch syndrome is critical in the prognostication and clinical management of patients with colorectal carcinoma.

We describe here a young woman who developed a locally aggressive rectal adenocarcinoma with intact MMR protein expression by immunohistochemistry and absence of histologic evidence of MMR deficiency-associated increased tumoral immune response. Germline DNA-targeted sequencing identified MSH2 variant p.R711P, initially classified as a variant of undetermined significance. Somatic tumoral DNA analysis revealed the identical MSH2 variant, high tumor mutational burden, and microsatellite instability, in addition to superimposed alterations in β2-microglobulin gene, possibly explaining the altered intratumoral immunity. Consequently, the patient was started on immunotherapy, leading to successful disease control (33 month follow-up).

The findings emphasize the utility of an integrative approach in the assessment of MMR status for determining candidacy for immunotherapy, especially in the setting of missense variants in MMR genes.

Defects in the DNA mismatch repair (MMR) pathway can predispose individuals to colorectal cancer (CRC), with germline mutations in this pathway leading to Lynch syndrome. Consequently, universal MMR testing is recommended for all newly diagnosed CRC patients to detect mismatch repair deficient (MMR-D) tumors, enabling informed treatment decisions. Given the increased potential for metachronous disease in patients with Lynch syndrome, the current guidelines for surgical management of Lynch-associated colon cancer recommend extended resection in patients under age 60.

A retrospective analysis of nonmetastatic CRC was performed from the National Cancer Database to evaluate the current trends and practice patterns in the surgical management of MMR-D colon cancer, as well as assess the factors influencing choice of surgical procedure.

From 2018 to 2020, 98,112 nonmetastatic CRC patients were identified, with 19.93% being MMR-D. MMR-D colon cancer patients were more likely to undergo extended resection than those with mismatch repair proficient tumors (9.4% versus 4.2%, P < 0.001). When accounting for approximately one-fourth of MMR-D colon cancers being attributable to Lynch syndrome, the frequency of extended resection was less than expected (9.4% versus 25%, P < 0.001). MMR-D patients under age 60 were more likely to undergo extended resection than those over age 60 (9% versus 3%) (odds ratio [OR] 3.57, 95% confidence interval [CI] 3.06-4.15). Several factors were associated with decreased rate of extended resection: uninsured (OR 0.42, 95% CI 0.21-0.84), Black race (OR 0.54, 95% CI 0.35-0.82), treatment at nonacademic centers (OR 0.74, 95% CI 0.56-0.97), and crowfly distance >25 miles (OR 1.98, 95% CI 1.14-3.45).

These findings provide valuable insight into the current surgical practice patterns in the management of MMR-D colon cancers and possibly colon cancers associated with Lynch syndrome.

Colorectal cancer (CRC) is a common cancer in Ireland. Of all CRCs, 2-4% are attributable to Lynch Syndrome (LS), the most common CRC predisposition syndrome. LS is caused by constitutional pathogenic variants (PVs) affecting mismatch repair (MMR) genes with resultant MMR protein deficiency (dMMR). Screening of all CRCs with MMR immunohistochemistry (IHC) testing is advocated to increase the detection of LS. However, successful implementation requires appropriate downstream management. In Ireland the traditional pathway involves referral to cancer genetics services to assess eligibility for genetic testing. Cancer genetics services in Ireland face many challenges in providing uniform access to timely healthcare with current wait times for assessment in excess of 1 year. An increasingly adopted pathway is that of mainstreaming, whereby genetic testing is managed locally by a multidisciplinary team member. Our institution therefore implemented an Advanced Nurse Practitioner (ANP)-led service with responsibility for the LS Diagnostic Pathway and mainstream genetic testing. Data was extracted from a prospectively maintained database of all newly diagnosed CRC patients discussed at our institutions CRC multidisciplinary meeting (MDM) between January 1st, 2023, and May 31st, 2024. MMR IHC testing was performed in 97.9% of the 385 patients diagnosed with CRC. The median time from histological confirmation of CRC to the availability of the MMR IHC report was 6 days. All 51 patients (100%) who required sequential tumor testing underwent BRAF V600 ± MLH1 promoter methylation testing. Additionally, 100% of the 14 patients eligible for mainstream genetic testing were referred to the ANP-led genetics service. The median time from the initial MDM discussion to the initiation of genetic testing was 69 days, while the median time from testing to the availability of results was 19 days. Patients received their results within a median of 21 days. MMR IHC testing increases the detection of LS through identification of dMMR tumours. Successful downstream delivery of clinical services, however, requires appropriate subsequent management, in a resource-limited environment. Our institutional experience demonstrates the feasibility, efficiency, and effectiveness of an ANP-led mainstreaming model of care for hereditary colorectal cancer.

Colorectal cancer (CRC) remains one of the major causes of cancer death worldwide. Chemotherapy continues to serve as the primary treatment modality, while immunotherapy is largely ineffective for the majority of CRC patients. Seminal discoveries have emphasized that modifying DNA damage response (DDR) mechanisms confers both cell-autonomous and immune-related vulnerabilities across various cancers. In CRC, approximately 15% of tumours exhibit alterations in the mismatch repair (MMR) machinery, resulting in a high number of neoantigens and the activation of the type I interferon response. These factors, in conjunction with immune checkpoint blockades, collectively stimulate anticancer immunity. Furthermore, although less frequently, somatic alterations in the homologous recombination (HR) pathway are observed in CRC; these defects lead to genome instability and telomere alterations, supporting the use of poly (ADP-ribose) polymerase (PARP) inhibitors in HR-deficient CRC patients. Additionally, other DDR inhibitors, such as Ataxia Telangiectasia and Rad3-related protein (ATR) inhibitors, have shown some efficacy both in preclinical models and in the clinical setting, irrespective of MMR proficiency. The aim of this review is to elucidate how preexisting or induced vulnerabilities in DNA repair pathways represent an opportunity to increase tumour sensitivity to immune-based therapies in CRC.

Colorectal cancer (CRC) is a severe gastrointestinal cancer and a leading cause of cancer-related deaths in Ghana. The potential role of gut Enterobacteriaceae in the increasing incidence of CRC in Ghana is yet to be thoroughly investigated. In this study, Enterobacteriaceae from CRC patients and healthy control participants were analyzed by whole genome sequencing to identify genomic features that are associated with CRC. Socio-demographic data showed a significant association between age and alcohol consumption and CRC. Escherichia coli was the most abundant Enterobacteriaceae isolated from the study participants and they were predominantly intestinal commensals. Escherichia coli isolates belonging to phylogroup D encoded the highest number of virulence genes. The agn43 and int genes were widespread in Escherichia coli isolates from the CRC patients. Multilocus sequence types of potentially pathogenic Escherichia coli from the CRC patients also encoded genes involved in aggregation, adherence and biofilm formation. The ampC2 and ampH antimicrobial resistance genes were also widespread in the genome of the Escherichia coli isolates. This study highlights the virulence tendencies of Escherichia coli from CRC patients and their ability to transfer virulence determinants to other Enterobacteriaceae residing in the gut.

Microsatellite instability high (MSI-H) and mismatch repair deficient (dMMR) tumor status have been demonstrated to predict patient response to immunotherapies. We developed and validated a next-generation sequencing (NGS)-based companion diagnostic (CDx) to detect MSI-H solid tumors via a comprehensive genomic profiling (CGP) assay, FoundationOne®CDx (F1CDx). To determine MSI status, F1CDx calculates the fraction of unstable microsatellite loci across >2000 loci using a fraction-based (FB) analysis. Across solid tumor types, F1CDx demonstrated a high analytical concordance with both PCR (n = 264) and IHC (n = 279) with an overall percent agreement (OPA) of 97.7% and 97.8%, respectively. As part of a retrospective bridging clinical study from KEYNOTE-158 Cohort K and KEYNOTE-164, patients with MSI-H tumors as determined by F1CDx demonstrated an objective response rate (ORR) of 43.0% to pembrolizumab. In real-world cancer patients from a deidentified clinicogenomic database, F1CDx was at least equivalent in assessing clinical outcome following immunotherapy compared with MMR IHC. Demonstrated analytical and clinical performance of F1CDx led to the pan-tumor FDA approval in 2022 of F1CDx to identify MSI-H solid tumor patients for treatment with pembrolizumab. F1CDx is an accurate, reliable, and FDA-approved method for the identification of MSI-H tumors for treatment with pembrolizumab.

The aim of the study was to test a universal screening strategy on endometrial cancer to evaluate its effectiveness to find Lynch Syndrome (LS) cases to two established clinical criteria: Amsterdam II criteria, and the revised Bethesda criteria to select cases for prescreening with immunohistochemistry (IHC). Cases were subsequently screened for germline disease causing variants regarding the DNA mismatch repair (MMR) genes.

IHC was performed on 221 endometrial cancer (EC) cases, using antibodies against the DNA mismatch repair proteins MLH1, PMS2, MSH2, and MSH6. MMR loss was found in 54 cases, and gene mutation screening was undertaken in 52 of those.

In this set of patients, the use of Amsterdam II criteria detected two (0.9%), the Bethesda criteria two (0.9%), and universal testing five (2.3%) cases of LS. The combination of universal testing and family history criteria resulted in detection of five patients (2.3%) with LS.

Based on our results and other similar studies to date we propose a screening protocol for LS on EC tumors with prescreening using IHC for the four MMR proteins on all new EC cases diagnosed before 70 years of age, followed by mutation screening of all tumors with loss of MSH2 and/or MSH6 or only PMS2, plus consideration for mutation screening of all LS genes in cases fulfilling the clinical Amsterdam II criteria regardless of MMR status on IHC.

The Implementing Universal Lynch Syndrome Screening (IMPULSS) study explained institutional variation in universal tumor screening (UTS) with the goal of identifying ways to aid organizational decision-makers in implementing and optimizing Lynch syndrome UTS programs.

After applying the Consolidated Framework for Implementation Research (CFIR 1.0) to analyze interviews with 66 stakeholders across 9 healthcare systems to develop a toolkit for implementation, we adapted the International Patient Decision Aid Standards (IPDAS) to assess toolkit potential to aid decision-making consistent with organizational values. We then conducted user testing with two experienced and four non-experienced implementers of UTS to improve the content and functionality of the toolkit and assess its acceptability and appropriateness.

Toolkit components were organized to address findings related to CFIR 1.0 constructs of evidence strength and quality, relative advantage, cost, engaging, planning, executing, and reflecting and evaluating. A home page was added to direct users to different sections based on whether they are deciding to implement UTS, planning for implementation, improving an existing UTS program, or considering a different approach to identify patients with Lynch syndrome. Upon initial evaluation, 31 of 64 IPDAS criteria were met by the original toolkit. All users rated the toolkit as acceptable and appropriate for assisting organizational decision-making and identified multiple areas for improvement. Numerous iterative changes were made to the toolkit, resulting in meeting 17 of the previously unmet IPDAS criteria.

We demonstrate the rigorous development of a toolkit guided by the CFIR and show how user testing helped improve the toolkit to ensure it is acceptable, appropriate, and meets most IPDAS criteria relevant to organizational values-based decision-making.

Lynch syndrome is an inherited condition which leads to an increased risk of colorectal, endometrial and ovarian cancer. Risk-reducing surgery is generally recommended to manage the risk of gynaecological cancer once childbearing is completed. The value of gynaecological colonoscopic surveillance as an interim measure or instead of risk-reducing surgery is uncertain. We aimed to determine whether gynaecological surveillance was effective and cost-effective in Lynch syndrome.

We conducted systematic reviews of the effectiveness and cost-effectiveness of gynaecological cancer surveillance in Lynch syndrome, as well as a systematic review of health utility values relating to cancer and gynaecological risk reduction. Study identification included bibliographic database searching and citation chasing (searches updated 3 August 2021). Screening and assessment of eligibility for inclusion were conducted by independent researchers. Outcomes were prespecified and were informed by clinical experts and patient involvement. Data extraction and quality appraisal were conducted and results were synthesised narratively. We also developed a whole-disease economic model for Lynch syndrome using discrete event simulation methodology, including natural history components for colorectal, endometrial and ovarian cancer, and we used this model to conduct a cost-utility analysis of gynaecological risk management strategies, including surveillance, risk-reducing surgery and doing nothing.

We found 30 studies in the review of clinical effectiveness, of which 20 were non-comparative (single-arm) studies. There were no high-quality studies providing precise outcome estimates at low risk of bias. There is some evidence that mortality rate is higher for surveillance than for risk-reducing surgery but mortality is also higher for no surveillance than for surveillance. Some asymptomatic cancers were detected through surveillance but some cancers were also missed. There was a wide range of pain experiences, including some individuals feeling no pain and some feeling severe pain. The use of pain relief (e.g. ibuprofen) was common, and some women underwent general anaesthetic for surveillance. Existing economic evaluations clearly found that risk-reducing surgery leads to the best lifetime health (measured using quality-adjusted life-years) and is cost-effective, while surveillance is not cost-effective in comparison. Our economic evaluation found that a strategy of surveillance alone or offering surveillance and risk-reducing surgery was cost-effective, except for path_PMS2 Lynch syndrome. Offering only risk-reducing surgery was less effective than offering surveillance with or without surgery.

Firm conclusions about clinical effectiveness could not be reached because of the lack of high-quality research. We did not assume that women would immediately take up risk-reducing surgery if offered, and it is possible that risk-reducing surgery would be more effective and cost-effective if it was taken up when offered.

There is insufficient evidence to recommend for or against gynaecological cancer surveillance in Lynch syndrome on clinical grounds, but modelling suggests that surveillance could be cost-effective. Further research is needed but it must be rigorously designed and well reported to be of benefit.

This study is registered as PROSPERO CRD42020171098.

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR129713) and is published in full in Health Technology Assessment; Vol. 28, No. 41. See the NIHR Funding and Awards website for further award information.

Lynch syndrome (LS) is a prevalent genetic condition associated with colorectal cancer (CRC). Accurate identification of LS patients is challenging, and a universal tumor screening approach has been recommended. We present the methodology and results of universal LS screening in our hospital's Pathology Department. This retrospective study analyzed CRC tumors from a 5-year period (2017-2021). Immunohistochemistry was used to assess MMR protein expression, followed by BRAF V600E analysis and MLH1 promoter methylation. Statistical analysis examined associations between clinicopathologic variables MMR status and LS-suspected tumors. The study analyzed 939 colorectal carcinomas, with 8.7% exhibiting mismatch repair (MMR) deficiency, significantly lower than previous research. After applying the algorithm, 24 LS-suspected cases were identified, accounting for 2.6% of tested patients and 29.3% of MMR-deficient tumors. Our study establishes the feasibility of universal testing for all new cases of CRC in detecting individuals at risk for LS, even in the absence of clinical information. To gain a comprehensive understanding of the MMR status in our population, further investigations are warranted.

Lynch syndrome (LS) is the most prevalent heritable form of colorectal cancer. Its early onset and high lifetime risk for colorectal cancer emphasize the necessity for effective chemoprevention. NFE2L2 (NRF2) is often considered a potential druggable target, and many chemopreventive compounds induce NRF2. However, although NRF2 counteracts oxidative stress, it is also overexpressed in colorectal cancer and may promote tumorigenesis. In this study, we evaluated the role of NRF2 in the prevention of LS-associated neoplasia. We found increased levels of NRF2 in intestinal epithelia of mice with intestinal epithelium-specific Msh2 deletion (MSH2ΔIEC) compared with C57BL/6 (wild-type) mice, as well as an increase in downstream NRF2 targets NAD(P)H dehydrogenase (quinone 1) and glutamate-cysteine ligase catalytic subunit. Likewise, NRF2 levels were increased in human MSH2-deficient LS tumors compared with healthy human controls. In silico analysis of a publicly accessible RNA sequencing LS dataset also found an increase in downstream NRF2 targets. Upon crossing MSH2ΔIEC with Nrf2null (MSH2ΔIECNrf2null) mice, we unexpectedly found reduced tumorigenesis in MSH2ΔIECNrf2null mice compared with MSH2ΔIEC mice after 40 weeks, which occurred despite an increase in oxidative damage in MSH2ΔIECNrf2null mice. The loss of NRF2 impaired proliferation as seen by Ki67 intestinal staining and in organoid cultures. This was accompanied by diminished WNT/β-catenin signaling, but apoptosis was unaffected. Microbial α-diversity increased over time with the loss of NRF2 based upon 16S rRNA gene amplicon sequencing of murine fecal samples. Altogether, we show that NRF2 protein levels are increased in MSH2 deficiency and associated neoplasia, but the loss of NRF2 attenuates tumorigenesis. Activation of NRF2 may not be a feasible strategy for chemoprevention in LS. Prevention Relevance: Patients with LS have an early onset and high lifetime risk for colorectal cancer. In this study, we show that NRF2 protein levels are increased in MSH2 deficiency and associated neoplasia, but the loss of NRF2 attenuates tumorigenesis. This suggests that NRF2 may not be a tumor suppressor in this specific context.

Universal screening of colorectal cancer (CRC) patients for Lynch syndrome (LS) through MisMatch Repair (MMR) testing is recommended. BRAF V600E mutation and/or MLH1 promoter methylation (Reflex Testing, RefT)generally rule out LS in MLH1-deficient (dMLH1) patients. We estimated the impact of RefTon genetic counseling (GC) and on the diagnostic yield of genetic testing (GT).

Overall, 3199 CRC patients were referred to our center between 2011 and 2021. Patients referred until January 2019 (n=2536) underwent universal MMR testing and were termed 'Cohort A'; among patients after February 2019 (n=663), 'Cohort B', RefT was also performed in dMLH1 patients.

Overall, 401/3199 patients (12.5%) were MMR-deficient (dMMR); 312 (77.8%) in cohort A and 89 (22.2%) inB; 346/401 were dMLH1 (86.3%), 262/312 (83.9%) in cohort A and 84/89 (94.3%) in B. In Cohort A, 91/312 (29.1%) dMMR patients were referred to GC, 69/91 (75.8%) were in the dMLH1 group; 57/69 (82.6%) dMLH1 patients underwent GT and 1/57 (1.7%) had LS. In Cohort B, 3/84 dMLH1 patients did not undergo BRAF testing. Three BRAF wt and not hypermethylated of the remaining 81 dMLH1 patients were referred to GC and GT, and one had LS. This diagnostic pathway reduced GC referrals by 96% (78/81) in Cohort B and increased the diagnostic yield of GT by about 20 times.

Our findings support RefT in dMLH1 CRC patients within the LS diagnostic pathway, as it reduces the number of GC sessions needed and increases the diagnostic yield of GT.

In April 2023, the National Comprehensive Cancer Network endorsed neoadjuvant immunotherapy for select patients with nonmetastatic mismatch repair deficient colon cancer. Approximately 15% of incident colon cancers are mismatch repair deficient, resulting in a distinct molecular subtype with high microsatellite instability that is responsive to immune checkpoint inhibition.

To describe the existing evidence supporting neoadjuvant immunotherapy for mismatch repair deficient, microsatellite unstable nonmetastatic colon cancer.

A medical librarian performed PubMed, Embase, and Web of Science searches most recently on April 24, 2023. The PubMed search was re-run on September 26, 2023, to identify any additional studies published between April 24 and September 26, 2023.

Two authors screened titles and abstracts in the published studies. The inclusion criteria were 1) English language, 2) adults with primary cancer of the colon, 3) nonmetastatic disease, 4) neoadjuvant immunotherapy, and 5) reporting on 10 or more cases.

Neoadjuvant immunotherapy.

Safety (grade 3+ treatment-related adverse events) and efficacy (complete pathologic responses).

From 7691 studies identified, 6370 were screened and 8 were included. Various agents, dosing regimens, and treatment durations were used, with durations of immunotherapy ranging from 1 to 16 cycles. Complete R0 resections were consistently achieved in 98% to 100% of resections. Of patients who received neoadjuvant immunotherapy and underwent resection, 50% to 91% had ypT0N0 pathology. The safety profiles were generally favorable, with grade 1 to 2 treatment-related adverse events (mostly immune-related) during immunotherapy reported in 22.2% to 70% of patients. Postoperative complications after neoadjuvant immunotherapy were reassuring, with no severe complications reported.

Small number of heterogeneous and uncontrolled studies precluding a meta-analysis.

Neoadjuvant immune checkpoint inhibition is associated with high rates of pathologic complete responses in locally advanced colon cancer. The literature is limited, particularly for postoperative outcomes, and more studies are needed to understand the safety and positioning of these regimens in the neoadjuvant context.

Colorectal carcinoma is one of the most common cancer types in men and women, responsible for both the third highest incidence of new cancer cases and the third highest cause of cancer deaths. In the last several decades, the molecular mechanisms surrounding colorectal carcinoma's tumorigenesis have become clearer through research, providing new avenues for diagnostic testing and novel approaches to therapeutics. Laboratories are tasked with providing the most current information to help guide clinical decisions. In this review, we summarize the current knowledge surrounding colorectal carcinoma tumorigenesis and highlight clinically relevant molecular testing.

Determination of microsatellite instability (MSI)/mismatch repair (MMR) status in cancer has several clinical implications. Our aim was to integrate MSI/MMR status from patients tested in Greece to assess the prevalence of MSI-high (MSI-H)/deficient MMR (dMMR) per tumor type, testing patterns over time and concordance between MSI and MMR status. We retrospectively recorded MSI/MMR testing data of patients with diverse tumor types performed in pathology and molecular diagnostics laboratories across Greece. Overall, 18 of 22 pathology and/or molecular diagnostics laboratories accepted our invitation to participate. In the 18 laboratories located across the country, 7916 tumor samples were evaluated for MSI/MMR status. MSI/MMR testing significantly increased in patients with colorectal cancer (CRC) and other tumor types overtime (p < 0.05). The highest prevalence was reported in endometrial cancer (47 of 225 patients, 20.9%). MSI-H/dMMR was observed in most tumor types, even in low proportions. Among 904 tumors assessed both for MSI and MMR status, 21 had discordant results (overall discordance rate, 2.3%). We reported MSI-H/dMMR prevalence rates in patients with diverse cancers, while demonstrating increasing referral patterns from medical oncologists in the country overtime. The anticipated high rate of concordance between MSI and MMR status in paired analysis was confirmed.

The recognized importance of microsatellite instability (MSI) in cancer has evolved considerably in the past 30 years. From its beginnings as a molecular predictor for Lynch syndrome, MSI first transitioned to a universal screening test in all colorectal and endometrial cancers, substantially increasing the identification of patients with Lynch syndrome among cancer patients. More recently, MSI has been shown to be a powerful biomarker of response to immune checkpoint blockade therapy across a diversity of tumor types, and in 2017 was granted Food and Drug Administration approval as the first tumor histology-agnostic biomarker for a cancer therapy. Focusing on colorectal cancer specifically, immune checkpoint blockade therapy has been shown to be highly effective in the treatment of both MSI-high (MSI-H) colon and rectal cancer, with data increasingly suggesting an early role for immune checkpoint blockade therapy in MSI-H colorectal tumors in the neoadjuvant setting, with the potential to avoid more toxic and morbid approaches using traditional chemotherapy, radiation therapy, and surgery. The success of MSI as an immune checkpoint blockade target has inspired ongoing vigorous research to identify new similar targets for immune checkpoint blockade therapy that may help to one day expand the reach of this revolutionary cancer therapy to a wider swath of patients and indications.

Colorectal cancer (CRC) is a complex disease with diverse etiologies and clinical outcomes. Despite considerable progress in development of CRC therapeutics, challenges remain regarding the diagnosis and management of advanced stage metastatic CRC (mCRC). In particular, the five-year survival rate is very low since mCRC is currently rarely curable. Over the past decade, cancer treatment has significantly improved with the introduction of cancer immunotherapies, specifically immune checkpoint inhibitors. Therapies aimed at blocking immune checkpoints such as PD-1, PD-L1, and CTLA-4 target inhibitory pathways of the immune system, and thereby enhance anti-tumor immunity. These therapies thus have shown promising results in many clinical trials alone or in combination. The efficacy and safety of immunotherapy, either alone or in combination with CRC, have been investigated in several clinical trials. Clinical trials, including KEYNOTE-164 and CheckMate 142, have led to Food and Drug Administration approval of the PD-1 inhibitors pembrolizumab and nivolumab, respectively, for the treatment of patients with unresectable or metastatic microsatellite instability-high or deficient mismatch repair CRC. Unfortunately, these drugs benefit only a small percentage of patients, with the benefits of immunotherapy remaining elusive for the vast majority of CRC patients. To this end, primary and secondary resistance to immunotherapy remains a significant issue, and further research is necessary to optimize the use of immunotherapy in CRC and identify biomarkers to predict the response. This review provides a comprehensive overview of the clinical trials involving immune checkpoint inhibitors in CRC. The underlying rationale, challenges faced, and potential future steps to improve the prognosis and enhance the likelihood of successful trials in this field are discussed.

MLH1, one of the MMR proteins, is linked to DNA replication, its role being to repair the incorrect DNA sequences and to replace them with proper ones. The loss of the MLH1 gene expression is part of Lynch syndrome which can lead to a series of cancers like colorectal and endometrial ones. The aim of this paper is to correlate the levels of MLH1 in four different bio-logical fluids with clinicopathological features in colorectal cancer patients in order to predict them with high probability. Therefore, a mathematical model with given code in Matlab has been proposed to get the clinicopathological features with high probability by only introducing the values for MLH1 concentrations. All these data can be obtained in a very short time even before surgery which can be very helpful the surgeon and the oncologist.

Four types of samples (whole blood, saliva, urine and tissue) were analyzed using stochastic microsensors; concentrations of MLH1 were determined and compared with different macroscopic and micro-scopic pathological features to obtain mathematical models for early, non-invasive diagnostic of colorectal adenocarcinoma.

There have been established criteria and mathematical models for tumor location, TNM grading system, depth of the tumor, lymphatic, vascular and perineural invasions and the presence of mucus in the tumoral mass.

By using whole blood, saliva and urine samples, the location can be approximated. The proposed mathematical models aimed to allow a minim/noninvasive characterization of the tumor and its location which can help the surgeon and the oncologist to choose faster the personalized treatment.

Background Microsatellite instability (MSI) is a genetic condition caused by errors in DNA repair genes that cause colorectal cancer (CRC). The literature contradicts the frequency of MSI in sporadic CRCs and its effect on prognosis. This study investigated the distribution of clinicopathologic features and the relationship between MSI and survival outcomes. Methodology This is a retrospective study of 101 consecutive cases of CRC and immunohistochemical studies. All cases were retrospectively reviewed and reevaluated by histological grade, lymphovascular invasion, perineural invasion, tumor borders, dirty necrosis, tumor-infiltrating lymphocytes (TILs), Crohn's-like lymphoid reaction, mucinous and medullary differentiation, and tumoral budding from pathological slides. An immunohistochemical study was performed in appropriate blocks for using MLH-1, MSH-2, MSH-6, and PMS-2. We collected the clinical stage, pathological tumor stage, lymph node metastasis, age, sex, tumor diameter, distant metastasis, localization, and survival information from patients' clinical data. Results There was no statistically significant difference between the two groups regarding age, gender, tumor diameter, histological grade, tumor border, dirty necrosis, TILs, N and M stage, perineural and lymphovascular invasion, mucinous differentiation, medullary differentiation, and tumor budding characteristics of the patients. The MSI-H group was more frequently located in the right colon and transverse colon (p < 0.001), and the T stage was higher among them than in the MSI-L group (p = 0.014). Upon multivariate regression analysis, MSI status had no significant effect on survival time. Age and stage N and M were independent prognostic factors for colon cancer prognosis. Conclusions Our study presented the distribution of clinicopathological features and their relationship with MSI for 101 regional CRC patients. MSI status was detected by immunohistochemistry. Identifying MSI in CRCs may help personalize therapy planning. As the distribution of the features may vary from population to population, further investigations are needed on this topic.

Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients' values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.

The incidence of colorectal cancer (CRC) in sub-Saharan Africa (SSA) is rising, due to improving cancer registration efforts on one hand and an increasing westernisation of diets and lifestyle on the other as well as increasing rates of comorbidities.

We present data for the clinical characteristics, pathology, treatments received, and survival outcomes of patients diagnosed with CRC at King Faisal Hospital (KFH) between January 2019 and May 2023. KFH is an urban tertiary hospital in Rwanda that provides chemotherapy and surgery to cancer patients. The data were extracted from electronic medical records, imaging and histopathology reports from the patient's time of diagnosis. We plotted Kaplan-Meier estimation of survival, defined as the time from presentation to death, within the study period (2019-2023).

Seventy-four patients diagnosed with CRC with complete information were identified in the KFH oncology records. The mean age at diagnosis was 54.6 years, with ages ranging between 22 and 81 years. At diagnosis, 24 (32.4%) patients were less than 50 years old and 29 (39.2%) were females. The rectum (36.5%) was the most common tumour location, and 58.1 tumours were left-sided. Most patients presented with Stage III (41.9%) or IV (35.1%) disease. Adenocarcinoma was the most common histological type (98.6%) including adenocarcinoma not otherwise specified (NOS) (86.5%), mucinous adenocarcinoma (10.8%), signet ring cell carcinoma (1.4%) and followed by squamous cell carcinoma (1.4%). In terms of treatment, 19 (25.7%) patients received only chemotherapy, 43 (58.1%) patients received neo-adjuvant or adjuvant chemotherapy, 9 (12.2%) of patients received both neo-adjuvant and adjuvant chemotherapy, 49 patients (66.2%) underwent surgery and 17 (23%) patients also received radiation. At the end of the follow up period, 63 (85.1%) patients remained in surveillance, 10 (13.5%) patients died, and 1 (1.3%) patient was lost to follow up. Mean overall survival was 45.5 (SD ± 2.0) months.

CRC patients presented at an advanced stage and required complex treatment regimens at KFH. Further epidemiologic and molecular research is needed to characterise CRC incidence and presentation at a national level in Rwanda as increasing westernisation continues to change the face of CRC in urban areas of SSA.

Lynch syndrome is an inherited condition, which increases the risk of numerous visceral malignancies and cutaneous tumors such as keratoacanthomas and sebaceous tumors. It is typically identified by immunohistochemistry of tissue taken from tumors or through genetic testing with next-generation sequencing. Diagnosing Lynch syndrome becomes more complex when the individual is mosaic for the relevant pathogenic variant. There are very few cases of this reported in the medical literature. It is even more unusual for the diagnosis to be made based on testing of a keratoacanthoma lesion. We report a case where immunohistochemistry of a keratoacanthoma helped make a diagnosis of mosaic Lynch syndrome. We will explore how mosaicism should be considered when a phenotype is strong, even if next-generation sequencing reports no pathogenic or likely pathogenic variant and how lesions such as keratoacanthomas can have a role in the early detection and treatment of future malignancies.

Colorectal cancer is a common malignant tumor in China, and its incidence in the elderly is increasing annually. Inflammatory bowel disease is a group of chronic non-specific intestinal inflammatory diseases, including ulcerative colitis and Crohn's disease.

To assess the effect of screening colonoscopy frequency on colorectal cancer mortality.

We included the clinicopathological and follow-up data of patients with colorectal cancer who underwent laparoscopic colectomy or open colectomy at our Gastrointestinal Department between January 2019 and December 2022. Surgical indicators, oncological indicators, and survival rates were compared between the groups. The results of 104 patients who met the above criteria were extracted from the database (laparoscopic colectomy group = 63, open colectomy group = 41), and there were no statistically significant differences in the baseline data or follow-up time between the two groups.

Intraoperative blood loss, time to first ambulation, and time to first fluid intake were significantly lower in the laparoscopic colectomy group than in the open colectomy group. The differences in overall mortality, tumor-related mortality, and recurrence rates between the two groups were not statistically significant, and survival analysis showed that the differences in the cumulative overall survival, tumor-related survival, and cumulative recurrence-free rates between the two groups were not statistically significant.

In elderly patients with colorectal cancer, laparoscopic colectomy has better short-term outcomes than open colectomy, and laparoscopic colectomy has superior long-term survival outcomes compared with open colectomy.

Advances in molecular genetics have revolutionized our understanding of the pathogenesis, progression, and therapeutic options for treating gastrointestinal (GI) cancers. This chapter provides a comprehensive overview of the molecular landscape of GI cancers, focusing on key genetic alterations implicated in tumorigenesis across various anatomical sites including GIST, colon and rectum, and pancreas. Emphasis is placed on critical oncogenic pathways, such as mutations in tumor suppressor genes, oncogenes, chromosomal instability, microsatellite instability, and epigenetic modifications. The role of molecular biomarkers in predicting prognosis, guiding treatment decisions, and monitoring therapeutic response is discussed, highlighting the integration of genomic profiling into clinical practice. Finally, we address the evolving landscape of precision oncology in GI cancers, considering targeted therapies and immunotherapies.

(1) Background: The human MutS homolog, hMSH2, is known to be involved in DNA mismatch repair and is responsible for maintaining the stability of the genome. When DNA damage occurs, MSH2 promotes cell apoptosis via the regulation of ATR/Chk2/p53 signal transduction, and MSH2 deficiency is also related to accelerated telomere shortening in humans. MSH2 missense mutations are involved in a defective DNA reparation process, and it can be implied in carcinogenesis, as it is already involved in well-known cancer-related syndromes such as Lynch syndrome. Human MSH6, which stands for mutS homolog 6, is a member of the MMR family that is responsible for the repair of post-replicative mismatched DNA bases. It is also one of the proteins with gene mutations that are associated with a high risk of developing Lynch syndrome, leading to a large series of tumors. (2) Methods: Patients and their clinical and pathological features were selected from the database of the project GRAPHSENSGASTROINTES and used accordingly, with ethics committee approval no. 32647/2018 awarded by the County Emergency Hospital from Targu-Mures. Analyses were conducted on whole blood, saliva, urine, and tumoral tissue samples using a stochastic method with stochastic microsensors. (3) Results: The results obtained using stochastic sensors were correlated with a series of macroscopic and microscopic pathological features for each sample type. Criteria or relationships were established for tumor location, vascular and perineural invasions, lymph node metastases, the presence of tumor deposits, and the presence of a mucus compound in the tumor mass. (4) Conclusions: The correlation between the concentrations of MSH2 in the four types of samples and the pathological features allowed for the fast characterization of a tumor, which can help surgeons and oncologists choose personalized treatments. Also, the colorectal tumor location was correlated with the concentration of MSH2 in whole blood, urine, and saliva. MSH6, which stands for mutS homolog 6, is not only useful in immunohistochemistry but in pathology practice as well. In this paper, the relationships between MSH6 levels in four biological fluids-whole blood, saliva, urine, and tissues-and tumor locations among the colorectal area, gross features, presence of a mucinous compound, molecular subtype, stroma features, and vascular invasions are presented.

Accurate determination of microsatellite instability (MSI) status is critical for optimal treatment in cancer patients. Conventional MSI markers can sometimes display subtle shifts that are difficult to interpret, especially in non-colorectal cases. We evaluated an experimental eight marker-panel including long mononucleotide repeat (LMR) markers for detection of MSI.

The eight marker-panel was comprised of five conventional markers (BAT-25, BAT-26, NR-21, NR-24, and NR-27) and three LMR markers (BAT-52, BAT-59 and BAT-62). MSI testing was performed against 300 specimens of colorectal, gastric, and endometrial cancers through PCR followed by capillary electrophoresis length analysis.

The MSI testing with eight marker-panel showed 99.3% (295/297) concordance with IHC analysis excluding 3 MMR-focal deficient cases. The sensitivity of BAT-59 and BAT-62 was higher than or comparable to that of conventional markers in gastric and endometrial cancer. The mean shift size was larger in LMR markers compared to conventional markers for gastric and endometrial cancers.

The MSI testing with eight maker-panel showed comparable performance with IHC analysis. The LMR markers, especially BAT-59 and BAT-62, showed high sensitivity and large shifts which can contribute to increased confidence in MSI classification, especially in gastric and endometrial cancers. Further study is needed with large number of samples for the validation of these LMR markers.

Stage II/III disease is the most predominant form of colorectal cancer, accounting for approximately 70% of cases. Furthermore, approximately 15% to 20% of patients with stage II/III disease have deficient mismatch repair or microsatellite instability-high colorectal cancer. However, there are no identified significant prognostic biomarkers for this disease.

To identify prognostic markers for patients with deficient mismatch repair/microsatellite instability-high colon cancer stage II/III.

Retrospective study design.

The study was conducted at a high-volume colorectal center, the Cancer Hospital, Chinese Academy of Medical Sciences.

Patients diagnosed with stage II/III deficient mismatch repair/microsatellite instability-high colon cancer who underwent curative surgery at the Cancer Hospital at the Chinese Academy of Medical Sciences between July 2015 and November 2018 were included.

The primary outcome measure was the influence of differentially mutated genes on progression-free survival.

The retrospective deficient mismatch repair/microsatellite instability-high cohort involved 32 patients and The Cancer Genome Atlas-microsatellite instability-high cohort involved 45 patients. Patients with deficient mismatch repair/microsatellite instability-high colon cancer had higher mutational frequencies of MKI67 , TPR , and TCHH than patients with microsatellite stable colon cancer. MKI67 , TPR , TCHH , and gene combination were significantly correlated with prognosis. The biomarker mutation-type colon cancer group had a higher risk of recurrence or death than did the wild-type group. Moreover, biomarker mutation-type tumors had more mutations in the DNA damage repair pathway and tumor mutational burden than did biomarker wild-type tumors.

This study was limited by its retrospective nature.

MKI67 , TPR , and TCHH may serve as potential diagnostic and prognostic biomarkers for deficient mismatch repair/microsatellite instability-high colon cancer stage II/III.

ANTECEDENTES:La enfermedad en estadio II/III es la forma más predominante de cáncer colorrectal y representa aproximadamente el 70% de los casos. Además, aproximadamente entre el 15% y el 20% de los pacientes con enfermedad en estadio II/III tienen reparación deficiente de errores de emparejamiento o inestabilidad de microsatélital alta. Sin embargo, no se han identificado biomarcadores pronósticos significativos para esta enfermedad.OBJETIVO:Este estudio tuvo como objetivo identificar marcadores pronósticos para pacientes con cáncer de colon con reparación deficiente de errores de emparejamiento/inestabilidad microsatelital alta en estadio II/III.DISEÑO:Diseño de estudio retrospectivo.ESCENARIO:El estudio se realizó en un centro colorrectal de alto volumen, el Hospital del Cáncer de la Academia China de Ciencias Médicas.PACIENTES:Pacientes diagnosticados con cáncer de colon en estadio II/III con reparación deficiente de errores de emparejamiento o inestabilidad de microsatélital alta que se sometieron a cirugía curativa en el Hospital del Cáncer de la Academia China de Ciencias Médicas entre julio de 2015 y noviembre de 2018.MEDIDAS DE RESULTADO PRINCIPALES:La medida de resultado primaria fue la influencia de los genes con mutaciones diferenciales en la supervivencia libre de progresión.RESULTADOS:La cohorte retrospectiva de reparación deficiente de errores de emparejamiento o inestabilidad de microsatélital alta y la cohorte de inestabilidad microsatelital alta del Atlas del Genoma del Cáncer involucraron a 32 y 45 pacientes, respectivamente. Los pacientes con de reparación deficiente de errores de emparejamiento/inestabilidad microsatélital alta tuvieron frecuencias mutacionales más altas de MKI67 , TPR y TCHH que los pacientes estables de microsatélites. MKI67 , TPR , TCHH , y la combinación de genes se correlacionaron significativamente con el pronóstico. El grupo de cáncer de colon de tipo mutación de biomarcador tenía un mayor riesgo de recurrencia o muerte que el grupo de mutación salvaje. Además, los tumores de tipo mutación de biomarcadores tenían más mutaciones en la vía de reparación del daño del ADN y la carga mutacional del tumor que los tumores de tipo salvaje de biomarcadores.LIMITACIONES:Este estudio estuvo limitado por su naturaleza retrospectiva.CONCLUSIONES:MKI67 , TPR , y TCHH pueden servir como posibles biomarcadores de diagnóstico y pronóstico para cáncer de colon en estadio II/III con reparación deficiente de errores de emparejamiento/inestabilidad microsatélital alta. (Traducción-Dr. Jorge Silva Velazco ).