Patients with pancreatic ductal adenocarcinoma (PDAC) commonly have occult metastatic dissemination and current standard staging methods have significant limitations in identifying these patients. A clinically available assay allows for the identification of mutant KRAS (mKRAS) circulating tumor DNA (ctDNA) from patient plasma and peritoneal fluid that may identify these patients and impact treatment decision making. We investigated the patterns of diagnostic and prognostic capabilities of mKRAS ctDNA in patients with localized PDAC.

Patients with non-metastatic PDAC were identified and underwent a full staging work-up during their first visit at our institution. Development of metastatic disease and long-term survival outcomes were assessed to compare between the mKRAS testing groups.

Between 2018 and 2022, 785 patients were evaluated. Among the 785 patients who underwent plasma mKRAS testing, 104 were mKRAS positive. Plasma mKRAS-positive patients were more likely to develop metastatic disease and had worse overall survival. In the 419 patients who underwent peritoneal mKRAS, 123 were mKRAS-positive and were more likely to harbor occult metastases or develop peritoneal rather than hematogenous metastases. For patients who underwent both baseline plasma and peritoneal mKRAS testing, any positive mKRAS test regardless of compartment was associated with worse outcomes.

Detection of mKRAS ctDNA in plasma and peritoneal fluid of patients with localized PDAC is not only feasible but also identifies those at high risk of metastatic progression and worse survival outcomes. It allows for better prognostication and can significantly impact subsequent treatment decisions, particularly in patients where an aggressive surgical approach is being considered.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal forms of cancer, characterized by a highly desmoplastic tumor microenvironment. One main risk factor is chronic pancreatitis (CP). Progression of CP to PDAC is greatly influenced by persistent inflammation promoting genomic instability, acinar-ductal metaplasia, and pancreatic intraepithelial neoplasia (PanIN) formation. Components of the extracellular matrix, including immune cells, can modulate this progression phase. This includes cells of the innate immune system, such as natural killer (NK) cells, macrophages, dendritic cells, mast cells, neutrophils, and myeloid-derived suppressor cells (MDSCs), either promoting or inhibiting tumor growth. On one hand, innate immune cells can trigger inflammatory responses that support tumor progression by releasing cytokines and growth factors, fostering tumor cell proliferation, invasion, and metastasis. On the other hand, they can also activate immune surveillance mechanisms, which can limit tumor development. For example, NK cells are cytotoxic innate lymphoid cells that are able to kill tumor cells, and active dendritic cells are crucial for a functioning anti-tumor immune response. In contrast, mast cells and MDSCs rather support a pro-tumorigenic tumor microenvironment that is additionally sustained by platelets. Once thought to play a role in hemostasis only, platelets are now recognized as key players in inflammation and cancer progression. By releasing cytokines, growth factors, and pro-angiogenic mediators, platelets help shape an immunosuppressive microenvironment that promotes fibrotic remodeling, tumor initiation, progression, metastasis, and immune evasion. Neutrophils and macrophages exist in different functional subtypes that can both act pro- and anti-tumorigenic. Understanding the complex interactions between innate immune cells, platelets, and early precursor lesions, as well as PDAC cells, is crucial for developing new therapeutic approaches that can harness the immune and potentially also the coagulation system to target and eliminate tumors, offering hope for improved patient outcomes.

Pancreatic cancer is characterized by late diagnosis, therapy resistance, and poor prognosis, necessitating the exploration of early carcinogenesis and prevention methods. Preclinical mouse models have evolved from cell line-based to human tumor tissue- or organoid-derived xenografts, now to humanized mouse models and genetically engineered mouse models (GEMMs). GEMMs, primarily driven by oncogenic Kras mutations and tumor suppressor gene alterations, offer a realistic platform for investigating pancreatic cancer initiation, progression, and metastasis. The incorporation of inducible somatic mutations and CRISPR-Cas9 screening methods has expanded their utility. To better recapitulate tumor initiation triggered by inflammatory cues, common pancreatic risk factors are being integrated into model designs. This approach aims to decipher the role of environmental factors as secondary or parallel triggers of tumor initiation alongside oncogenic burdens. Emerging models exploring pancreatitis, obesity, diabetes, and other risk factors offer significant translational potential. This review describes current mouse models for studying pancreatic carcinogenesis, their combination with inflammatory factors, and their utility in evaluating pathogenesis, providing guidance for selecting the most suitable models for pancreatic cancer research.

The tumor microenvironment (TME) plays a crucial role in cancer development and spreading being considered as "the dark side of the tumor". Within this term tumor cells, immune components, supporting cells, extracellular matrix and a myriad of bioactive molecules that synergistically promote tumor development and therapeutic resistance, are included. Recent findings revealed the profound impacts of TME on cancer development, serving as physical support, critical mediator and biodynamic matrix in cancer evolution, immune modulation, and treatment outcomes. TME targeting strategies built on vasculature, immune checkpoints, and immuno-cell therapies, have paved the way for revolutionary clinical interventions. On this basis, the relevance of pre-clinical and clinical investigations has rapidly become fundamental for implementing novel therapeutical strategies breaking cell-cell and cell -mediators' interactions between TME components and tumor cells. This review summarizes the key players in the breast and pancreatic TME, elucidating the intricate interactions among cancer cells and their essential role for cancer progression and therapeutic resistance. Different tumors such breast and pancreatic cancer have both different and similar stroma features, that might affect therapeutic strategies. Therefore, this review aims to comprehensively evaluate recent findings for refining breast and pancreatic cancer therapies and improve patient prognoses by exploiting the TME's complexity in the next future.

The clinical relevance of high-grade pancreatic intraepithelial neoplasia (PanIN) at the pancreatic transection margin (PTM) during resection of pancreatic ductal adenocarcinoma (PDAC) remains unclear.

A total of 358 patients who underwent R0 resection for PDAC between January 2010 and December 2022 were included. The permanent sections used for the intraoperative frozen section diagnosis of PTM were evaluated for the PanIN grade.

Among 358 patients, 35 patients had low-grade PanIN (9.8%), and 17 had high-grade PanIN (4.7%) at the PTM. The 2-year overall survival (OS), disease-free survival (DSS), and relapse-free survival (RFS) did not differ markedly among patients with normal epithelium, low-grade PanIN, or high-grade PanIN at the margin. As the clinical features differed between patients with high-grade PanIN at the PTM and those without, we adjusted the patients' background factors using propensity score matching. The 2-year OS, DSS, and RFS rates were not significantly different between the groups. In addition, we investigated the details of 17 cases of high-grade PanIN in the PTM. The analysis revealed that 11 patients experienced recurrence after surgery. Among them, two cases of T1N0 showed recurrence in the remnant pancreas more than 2 years after surgery, while nine cases exhibited recurrence outside the remnant pancreas, such as the liver and lungs, within 2 years.

Patients with high-grade PanIN at the PTM did not show a significantly different prognosis than those without; however, recurrence in the remnant pancreas was observed in long-term survivors. Therefore, rigorous long-term follow-up is essential for such patients.

Pancreatic ductal adenocarcinomas (PDACs) with wild-type KRAS constitute a small fraction of PDACs, and these tumors were recently shown to harbor frequent actionable oncogenic mutations and fusions. However, the clinicopathological features of KRAS wild-type PDAC have not been well studied. Additionally, precancerous lesions occurring in patients with KRAS wild-type PDACs have rarely been characterized. Here, we investigated the clinicopathological characteristics and outcomes of 75 patients with KRAS wild-type PDAC. Molecular analyses were performed in 40 patients using targeted DNA and whole-exome sequencing and targeted RNA sequencing. We demonstrated that patients with metastatic PDAC with wild-type KRAS were younger (median 59.5 years) than those with mutated KRAS (median 67 years, p < 0.000055). The wild-type KRAS status was not a significant prognostic factor for metastatic disease. Molecularly, genes in the RAS pathway are frequently mutated or rearranged (46%, 16/35), including mutations in BRAF, NRAS, HRAS, EGFR, MAP2K1, FGFR1, FGFR3 and ERBB4 and fusions of FGFR2 (FGFR2::CCDC147, FGFR2::CAT, FGFR2::TXLNA), ALK (STRN::ALK, EML4::ALK), and BRAF (TRIP11::BRAF). Mismatch repair deficiency was identified in 10% (4/39) of patients. Potentially actionable alterations were identified frequently in KRAS wild-type PDACs (30%, 12/40), in which nontubular-type carcinomas were significantly enriched with actionable alterations compared with tubular adenocarcinomas [67% (6/9) versus 16% (5/31); p = 0.007]. Finally, we investigated the precursors of PDACs in 13 pancreatectomy specimens from patients with KRAS wild-type PDAC. We identified three pancreatic intraepithelial neoplasias (PanINs) and two intraductal papillary mucinous neoplasms (IPMNs) harboring oncogenic fusions of ALK and BRAF and driver mutations in BRAF and AKT1. This study suggests that in the context of unmutated KRAS, PDAC is driven by alternative oncogenic mutations or fusions of RAS pathway genes, which may be introduced during the early phase of tumorigenesis. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Pancreatic cancer is frequently a lethal disease with an aggressive tumour biology often presenting with non-specific symptoms. Median survival is approximately 4 months with a 5-year survival of 13%. Surveillance is recommended in individuals with familial pancreatic cancer, specific mutations, and high-risk intraductal papillary mucinous neoplasm, as they are at high risk of developing pancreatic cancer. Chemotherapy combined with surgical resection remains the cornerstone of treatment. However, only a small subset of patients are candidates for surgery. Multi-agent chemotherapy has improved survival in the palliative setting for patients with metastatic disease, as (neo)adjuvant and induction therapy have in patients with borderline resectable and locally advanced pancreatic. Given that pancreatic cancer is predicted to become the second leading cause of cancer-related death by 2030, novel therapies are urgently needed.

Pancreatic Ductal Adenocarcinoma (PDAC) belongs to the types of cancer with the highest lethality. It is also remarkably chemoresistant to the few available cytotoxic therapeutic options. PDAC is characterized by limited mutational heterogeneity of the known driver genes, KRAS, CDKN2A, TP53, and SMAD4, observed in both early-stage and advanced tumors. In this review, we summarize the two proposed models of genetic evolution of pancreatic cancer. The gradual or stepwise accumulated mutations model has been widely studied. On the contrary, less evidence exists on the more recent simultaneous model, according to which rapid tumor evolution is driven by the concurrent accumulation of genetic alterations. In both models, oncogenic KRAS mutations are the main initiating event. Here, we analyze the emerging topic of KRAS allelic imbalances and how it arises during tumor evolution, as it is often detected in advanced and metastatic PDAC. We also summarize recent evidence on how it affects tumor biology, metastasis, and response to therapy. To this extent, we highlight the necessity to include studies of KRAS allelic frequencies in the design of future therapeutic strategies against pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) poses a significant challenge for early diagnosis due to the lack of sensitive and specific biomarkers. This encouraged us to explore the diagnostic value of cancer-derived small extracellular vesicles (sEVs) as early detection biomarkers. We previously showed that the recombinant malaria protein VAR2CSA (rVAR2) selectively binds to oncofetal chondroitin sulfate (ofCS) on the surfaces of cancer cells, which might be useful for identifying cancer-derived sEVs. Indeed, flow cytometry revealed strong ofCS expression in PDAC cell-derived sEVs, as evidenced by the presence of mutant KRAS, a common genetic alteration in PDAC. Plasma from PDAC patients showed significantly higher ofCS+ sEV levels compared to healthy donors and patients with benign gastrointestinal diseases. ROC analysis for ofCS+ sEVs revealed an AUC of 0.9049 for the detection of all-stage and 0.9222 for early-stage PDAC. Notably, mutant KRAS was also detected in these patient-derived sEVs. Most intriguingly, combining ofCS+ sEVs and CA19-9 resulted in an AUC of 0.9707 for the detection of early PDAC. Our study demonstrates that rVAR2 is suitable for detecting ofCS+ cancer-derived sEVs in plasma, thereby providing high efficiency for identifying PDAC patients among a diverse population. These findings suggest that rVAR2-based sEV detection could serve as a powerful diagnostic tool to improve patient survival through early detection.

Primary sclerosing cholangitis (PSC) is a chronic liver disease characterised by inflammation and fibrosis of the bile ducts, conferring an increased risk of cholangiocarcinoma (CCA). However, detecting CCA early in PSC patients remains challenging due to the limited sensitivity of conventional diagnostic methods, including imaging or bile duct brush cytology during endoscopic retrograde cholangiopancreatography (ERCP). This study aims to evaluate the potential of bile cell-free DNA (cfDNA) mutational analysis, termed the Bilemut assay, as a tool for CCA detection in PSC patients.

Sixty-three PSC patients undergoing ERCP due to biliary strictures were prospectively recruited. Bile samples were collected, and cfDNA was extracted and analysed using the Oncomine Pan-Cancer Cell-Free assay. Twenty healthy liver donors were included for comparison. Samples with a mutant allele frequency (MAF) ≥ 0.1% were considered positive. Correlations between mutational status and clinical characteristics were assessed.

cfDNA mutational analysis was successful in all bile samples. Mutations predominantly in KRAS, GNAS, and TP53 were detected in 36.5% (23/63) of PSC patients, compared to 10% (2/20) of healthy donors (p = 0.0269). The clinical characteristics of Bilemut-positive and -negative patients were comparable, though there was a trend towards a lower prevalence of inflammatory bowel disease in the Bilemut-positive group. Among PSC patients diagnosed with CCA during follow-up, 75% were Bilemut-positive, suggesting an association between mutational status and malignancy risk.

Mutational analysis of cfDNA obtained from bile collected from PSC patients undergoing ERCP is feasible. Implementing the Bilemut assay may help identify patients needing closer surveillance and further imaging studies.

Pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasms (IPMNs) are pancreatic ductal adenocarcinoma (PDAC) precursor lesions. Detecting these precursors and monitoring their progression are crucial for early PDAC diagnosis. Digital PCR (dPCR) is a highly sensitive nucleic acid quantification technique and offers a cost-effective option for patient follow-up. However, the clinical utility of conventional dPCR is restricted by multiplexing constraints, particularly due to the challenge of simultaneously quantifying multiple mutations and amplifications. In this study, we applied highly multiplexed dPCR and melting curve analysis to simultaneously measure single nucleotide mutations and amplifications of KRAS and GNAS. The developed 14-plex assay included both wild-type and mutant KRAS, a common driver gene in both PanIN and IPMN, and GNAS, which is specifically mutated in IPMN, along with RPP30, a reference gene for copy number alterations (CNAs). This multiplex dPCR method detected all target mutations with a limit of detection below 0.2% while quantifying CNAs. Additionally, the assay accurately quantified variant allele frequencies in liquid biopsy and tissue samples from both pancreatic neoplasm precursor and PDAC patients, indicating its potential for use in comprehensive patient follow-up.

Pancreatic ductal adenocarcinoma (PDAC) shows limited response to chemotherapy, partly due to the absence of effective biomarkers for personalized treatment. Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations are found in 90% of PDAC cases, and tumors dependent on KRAS (dKRAS) can be identified using gene expression signature scores. Previous research indicates that dKRAS-PDAC cells are sensitive to decitabine (DEC), an FDA-approved drug for hematological cancers, though its use in solid tumors is limited by side effects. We discovered that low-dose DEC combined with the poly (ADP-ribose) polymerase (PARP) inhibitor olaparib (OLA) enhances antitumor activity in dKRAS-PDAC. DEC induces DNA damage and activates the ataxia telangiectasia (ATR)/ataxia telangiectasia mutated (ATM)-mediated DNA damage response (DDR), with PARP1-mediated repair playing a key role. Inhibiting PARP with OLA further improves efficacy, even in BRCA1/2-wild-type and homologous recombination (HR)-proficient tumors but not in KRAS-independent tumors. The combination was especially effective in dKRAS-PDAC with a BRCA2 mutation, preventing metastasis growth. Our results support the clinical evaluation of DEC+OLA in PDAC.

Background: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer, able to thrive in a challenging tumor microenvironment. Current standard therapies, including surgery, radiation, chemotherapy, and chemoradiation, have shown a dismal survival prognosis, resulting in less than a year of life in the metastatic setting. Methods: The pressing need to find better therapeutic methods brought about the discovery of new targeted therapies against the infamous KRAS mutations, the major oncological drivers of PDAC. Results: The most common KRAS mutation is KRASG12D, which causes a conformational change in the protein that constitutively activates downstream signaling pathways driving cancer hallmarks. Novel anti-KRASG12D therapies have been developed for solid-organ tumors, including small compounds, pan-RAS inhibitors, protease inhibitors, chimeric T cell receptors, and therapeutic vaccines. Conclusions: This comprehensive review summarizes current knowledge on the biology of KRAS-driven PDAC, the latest therapeutic options that have been experimentally validated, and developments in ongoing clinical trials.

First-line chemotherapy (5-fluorouracil, leucovorin, irinotecan, and oxaliplatin [FOLFIRINOX]) benefits few patients with metastatic pancreatic ductal adenocarcinoma (mPDAC). Prognostic markers for treatment-related survival are needed. This study validated the added benefit of whole-genome sequencing (WGS) to transcriptome-based classification in modeling FOLFIRINOX-related survival.

Patients with mPDAC planning to start FOLFIRINOX were included in a prospective nationwide cohort. Pretreatment biopsies were submitted to WGS and RNA sequencing. Samples of non-FOLFIRINOX-treated patients were included for exploratory analyses.

WGS was performed in biopsies from 108 FOLFIRINOX-treated patients and 51 non-FOLFIRINOX-treated patients. 12% of the tumors were KRAS wild type. These tumors had more targetable alterations (42% vs. 17%) and were associated with a longer median overall survival (mOS) than KRAS mutant tumors (7.8 months in KRAS mutant vs. 17.7 months in wild-type tumors, p = 0.0024). Transcriptome-based clustering revealed a tumor subgroup showing low classical and basal-like gene expression, enriched for KRAS wild-type status (p < 0.0001), a so-called "classifier-negative" subtype. The gene expression of these classifier-negative tumors correlated with neural-like signatures. For patients with a homologous recombination-deficient (HRD) tumor, mOS was not increased (8.0 months in homologous recombination-proficient [HRP] vs. 13.3 months in HRD tumors, p = 0.21).

KRAS wild-type tumors are a distinct PDAC subgroup with a better prognosis. Consequently, KRAS status assessment before transcriptome-based subtyping can stratify patients into three prognostic molecular subgroups (KRAS wild type, KRAS mutant classical, and KRAS mutant basal like). This integrative way of classification should be validated prior to incorporation in diagnostic practice.

ZonMw "Good Use of Medicine" program (848101012).

CRISPR/Cas9-mediated genome editing has the potential to delete PD-L1 both on the cell surface and inside the cell, thereby inhibiting tumor growth and migration and overcoming immunosuppression. ZG16, with its lectin structure, can reduce PD-L1 expression on the cell surface. However, direct comparison of two approaches on PD-L1 expression in Pancreatic ductal adenocarcinoma (PDAC) cells has not yet been investigated. In this study, we established two Panc-1 cell line: one with PD-L1 knockout and another with ZG16 overexpression. Both methods promoted the polarization of tumor-associated macrophages (TAMs) to the M1 phenotype, as indicated by increased levels of the M1 marker CD11c+ in vitro and in vivo. Meanwhile, we observed a reduction in the M2 marker CD206+, upregulation of immune activation-related cytokines/chemokines, and a decrease in immunosuppressive cytokines and tumor angiogenesis factors. In summary, both PD-L1 knockout and ZG16 overexpression represent promising approaches for PDAC treatment.

Pancreatic intraepithelial neoplasia (PanIN) is the most common precursor lesion of pancreatic ductal adenocarcinoma (PDAC), which has poor prognosis with a short median overall survival of 6-12 months and a low 5-year survival rate of approximately 3%. It is crucial to remove PanIN lesions to prevent the development of invasive PDAC, as PDAC spreads rapidly outside the pancreas. This review aims to provide the latest knowledge on PanIN risk, pathology, cellular origin, genetic susceptibility, and diagnosis, while identifying research gaps that require further investigation in this understudied area of precancerous lesions. PanINs are classified into PanIN 1, PanIN 2, and PanIN 3, with PanIN 3 having the highest likelihood of developing into invasive PDAC. Differentiating between PanIN 2 and PanIN 3 is clinically significant. Genetic alterations found in PDAC are also present in PanIN and increase with the grade of PanIN. Imaging methods alone are insufficient for distinguishing PanIN, necessitating the use of genetic and molecular tests for identification. In addition, metabolomics technologies and miRNAs are playing an increasingly important role in the field of cancer diagnosis, offering more possibilities for efficient identification of PanIN. Although detecting and stratifying the risk of PanIN poses challenges, the combined utilization of imaging, genetics, and metabolomics holds promise for improving patient survival in this field.

Despite the high prevalence of KRAS alterations in pancreatic ductal adenocarcinoma (PDAC), the clinical impact of common KRAS mutations with different cytotoxic regimens is unknown. This evidence is important to inform current treatment and provide a benchmark for emergent targeted KRAS therapies in metastatic PDAC.

To assess the clinical implications of common KRAS G12 mutations in PDAC and to compare outcomes of standard-of-care multiagent therapies across these common mutations.

This retrospective cohort study obtained deidentified clinical data for 5382 patients from a nationwide (US-based) clinicogenomic database. The deidentified data originated from approximately 280 US cancer clinics (approximately 800 sites of care). Patients diagnosed with metastatic PDAC from February 9, 2010, to September 20, 2022, and with sufficient follow-up and treatment data were included.

Median overall survival (OS) and time to next treatment (TTNT) were calculated for each KRAS mutation group. Hazard ratios (HRs) were generated using multivariate Cox proportional hazards models for KRAS mutations and mutation-treatment combinations.

A total of 2433 patients with PDAC were included in the analysis (mean age at first treatment, 67.0 [range, 66.0-68.0] years; 1340 male [55.1%]). Among 2023 patients with KRAS mutations, those with G12R had the longest median TTNT (6.0 [95% CI, 5.2-6.6] months) and the longest median OS (13.2 [95% CI, 10.6-15.2] months). Patients with KRAS G12D and G12V mutations had a significantly higher risk of disease progression (HRs, 1.15; [95% CI, 1.04-1.29; P = .009] and 1.16 [95% CI, 1.04-1.30; P = .01], respectively) and death (HRs, 1.29 [95% CI, 1.15-1.45; P < .001] and 1.23 [95% CI, 1.09-1.39; P < .001], respectively) compared with KRAS wild type. The FOLFIRINOX regimen (fluorouracil, irinotecan, oxaliplatin, and leucovorin) had a significantly lower risk of treatment progression and death than gemcitabine with (HRs, 1.19 [95% CI, [1.09-1.29; P < .001] and 1.18 [95% CI, 1.07-1.29; P < .001], respectively) or without (HRs, 1.37 [95% CI, 1.11-1.69; P = .003] and 1.41 [95% CI 1.13-1.75; P = .002], respectively) nab-paclitaxel across all patients.

In this cohort study of 2433 patients with PDAC, KRAS G12D and G12V mutations were associated with worse patient outcomes compared with KRAS wild type. KRAS G12R was associated with more favorable patient outcomes, and FOLFIRINOX was associated with better patient outcomes than gemcitabine-based therapies. These findings highlight the need for more effective systemic therapies for these groups of patients.

Cancer has long been believed to be a genetic disease caused by the accumulation of mutations in key genes involved in cellular processes. However, recent advances in sequencing technology have demonstrated that cells with cancer driver mutations are also present in normal tissues in response to aging, environmental damage, and chronic inflammation, suggesting that not only intrinsic factors within cancer cells, but also environmental alterations are important key factors in cancer development and progression. Pancreatic cancer tissue is mostly comprised of stromal cells and immune cells. The desmoplasmic microenvironment characteristic of pancreatic cancer is hypoxic and hypotrophic. Pancreatic cancer cells may adapt to this environment by rewiring their metabolism through epigenomic changes, enhancing intrinsic plasticity, creating an acidic and immunosuppressive tumor microenvironment, and inducing noncancerous cells to become tumor-promoting. In addition, pancreatic cancer has often metastasized to local and distant sites by the time of diagnosis, suggesting that a similar mechanism is operating from the precancerous stage. Here, we review key recent findings on how pancreatic cancers acquire plasticity, undergo metabolic reprogramming, and promote immunosuppressive microenvironment formation during their evolution. Furthermore, we present the following two signaling pathways that we have identified: one based on the small G-protein ARF6 driven by KRAS/TP53 mutations, and the other based on the RNA-binding protein Arid5a mediated by inflammatory cytokines, which promote both metabolic reprogramming and immune evasion in pancreatic cancer. Finally, the striking diversity among pancreatic cancers in the relative importance of mutational burden and the tumor microenvironment, their clinical relevance, and the potential for novel therapeutic strategies will be discussed.

The development of pancreatic cancer requires both, acquisition of an oncogenic mutation in KRAS as well as an inflammatory insult. However, the physiological causes for pancreatic inflammation are less defined. We show here that oncogenic KRas-expressing pre-neoplastic lesion cells upregulate coxsackievirus (CVB) and adenovirus receptor (CAR). This facilitates infections from enteroviruses such as CVB3, which can be detected in approximately 50% of pancreatic cancer patients. Moreover, using an animal model we show that a one-time pancreatic infection with CVB3 in control mice is transient, but in the presence of oncogenic KRas drives chronic inflammation and rapid development of pancreatic cancer. We further demonstrate that a knockout of CAR in pancreatic lesion cells blocks these CVB3-induced effects. Our data demonstrate that KRas-caused lesions promote the development of pancreatic cancer by enabling certain viral infections.

Mutant KRAS is the main oncogenic driver in pancreatic ductal adenocarcinomas (PDACs). However, the clinical and phenotypic implications of harboring different mutant KRAS alleles remain poorly understood.

To characterize the potential morphologic and clinical outcome differences in PDACs harboring distinct mutant KRAS alleles.

Cohort 1 consisted of 127 primary conventional PDACs with no neoadjuvant therapy, excluding colloid/mucinous, adenosquamous, undifferentiated, and intraductal papillary mucinous neoplasm-associated carcinomas, for which an in-house 42-gene mutational panel had been performed. A morphologic classification system was devised wherein each tumor was assigned as conventional, papillary/large duct (P+LD, defined as neoplastic glands with papillary structure and/or with length ≥0.5 mm), or poorly differentiated (when the aforementioned component was 60% or more of the tumor). Cohort 2 was a cohort of 88 PDACs in The Cancer Genome Atlas, which were similarly analyzed.

In both cohorts, there was significant enrichment of P+LD morphology in PDACs with KRAS G12V and G12R compared with G12D. In the entire combined cohort, Kaplan-Meier analyses showed longer overall survival (OS) with KRAS G12R as compared with G12D (median OS of 1255 versus 682 days, P = .03) and in patients whose PDACs displayed P+LD morphology as compared with conventional morphology (median OS of 1175 versus 684 days, P = .04). In the adjuvant-only subset, KRAS G12R had the longest OS compared with G12D, G12V, and other alleles (median OS unreached/undefined versus 1009, 1129, and 1222 days, respectively).

PDACs with different mutant KRAS alleles are associated with distinct morphologies and clinical outcomes, with KRAS G12R allele associated with P+LD morphology and longer OS when compared with G12D using Kaplan-Meier studies.

Perineural invasion (PNI) represents a unique biological feature associated with poor prognosis in pancreatic ductal adenocarcinoma (PDAC), especially in the presence of KRAS mutations. Extracellular vesicle (EV)-packaged circular RNAs (circRNAs) function as essential mediators of tumor microenvironment communication, triggering PDAC cell invasion and distant metastasis. However, the regulatory mechanisms of EV-packaged circRNAs in the PNI of KRAS-mutant PDAC have not yet been elucidated. Herein, a KRASG12D mutation-responsive EV-packaged circRNA, circPNIT, which positively correlated with PNI in PDAC patients is identified. Functionally, KRASG12D PDAC-derived EV-packaged circPNIT promoted axonogenesis and PNI both in vitro and in vivo. Mechanistically, the circPNIT-mediated Rab5B-CD109 interplay bypassed traditional endosomal trafficking to anchor Rab5B to the lipid rafts of multivesicular bodies and packaged circPNIT into CD109+ EVs. Subsequently, CD109+ EVs delivered circPNIT to neurons by binding to TRPV1 and facilitating DSCAML1 transcription-induced axonogenesis, which in turn enhanced the PNI by activating the GFRα1/RET pathway. Importantly, circPNIT-loaded CD109+ EVs are established to dramatically promote PNI in a KRASG12D/+ Trp53R172H/+ Pdx-1-Cre mouse model. Collectively, the findings highlight the mechanism underlying how EV-packaged circRNAs mediate the PNI of KRAS-mutant PDAC cells through the Rab5B endosomal bypass, identifying circPNIT as an effective target for the treatment of neuro-metastatic PDAC.

Recent studies have shown that long noncoding RNAs (lncRNAs) play pivotal roles in the development and progression of cancer. In the present study, we aimed to identify lncRNAs associated with lymph node metastasis in pancreatic ductal adenocarcinoma (PDAC). We analyzed data from The Cancer Genome Atlas (TCGA) database to screen for genes overexpressed in primary PDAC tumors with lymph node metastasis. Our screen revealed 740 genes potentially associated with lymph node metastasis, among which were multiple lncRNA genes located in the HOXA locus, including HOXA11-AS. Elevated expression of HOXA11-AS was associated with more advanced tumor stages and shorter overall survival in PDAC patients. HOXA11-AS knockdown suppressed proliferation and migration of PDAC cells. RNA-sequencing analysis revealed that HOXA11-AS knockdown upregulated interferon lambda (IFNL) family genes and downregulated high-mobility group box (HMGB) family genes in PDAC cells. Moreover, HMGB3 knockdown suppressed proliferation and migration by PDAC cells. These results suggest that HOXA11-AS contributes to PDAC progression, at least in part, through regulation of IFNL and HMGB family genes and that HOXA11 AS is a potential therapeutic target in PDAC.

This review explores the progression of pancreatic intraepithelial neoplasia (PanIN) to pancreatic ductal adenocarcinoma through a dual lens of intrinsic molecular alterations and extrinsic microenvironmental influences. PanIN development begins with Kirsten rat sarcoma viral oncogene (KRAS) mutations driving PanIN initiation. Key additional mutations in cyclin-dependent kinase inhibitor 2A (CDKN2A), tumor protein p53 (TP53), and mothers against decapentaplegic homolog 4 (SMAD4) disrupt cell cycle control and genomic stability, crucial for PanIN progression from low-grade to high-grade dysplasia. Additional molecular alterations in neoplastic cells, including epigenetic modifications and chromosomal alterations, can further contribute to neoplastic progression. In parallel with these alterations in neoplastic cells, the microenvironment, including fibroblast activation, extracellular matrix remodeling, and immune modulation, plays a pivotal role in PanIN initiation and progression. Crosstalk between neoplastic and stromal cells influences nutrient support and immune evasion, contributing to tumor development, growth, and survival. This review underscores the intricate interplay between cell-intrinsic molecular drivers and cell-extrinsic microenvironmental factors, shaping PanIN predisposition, initiation, and progression. Future research aims to unravel these interactions to develop targeted therapeutic strategies and early detection techniques, aiming to alleviate the severe impact of pancreatic cancer by addressing both genetic predispositions and environmental influences.

Pancreatic ductal adenocarcinoma (PDAC) represents the complexity of interaction between cancer and cells of the tumor microenvironment (TME). Immune cells affect tumor cell behavior, thus driving cancer progression. Cancer-associated fibroblasts (CAFs) are responsible of the desmoplastic and fibrotic reaction by regulating deposition and remodeling of extracellular matrix (ECM). As tumor-promoting cells abundant in PDAC ECM, CAFs represent promising targets for novel anticancer interventions. However, relevant clinical trials are hampered by the lack of specific markers and elusive differences among CAF subtypes. Indeed, while single-cell transcriptomic analyses have provided important information on the cellular constituents of PDACs and related molecular pathways, studies based on the identification of protein markers in tissues aimed at identifying CAF subtypes and new molecular targets result incomplete.

Herein, we applied multiplexed Imaging Mass Cytometry (IMC) at single-cell resolution on 8 human PDAC tissues to depict the PDAC composing cells, and profiling immune cells, endothelial cells (ECs), as well as endocrine cells and tumor cells.

We focused on CAFs by characterizing up to 19 clusters distinguished by phenotype, spatiality, and interaction with immune and tumor cells. We report evidence that specific subtypes of CAFs (CAFs 10 and 11) predominantly are enriched at the tumor-stroma interface and closely associated with tumor cells. CAFs expressing different combinations of FAP, podoplanin and cadherin-11, were associated with a higher level of CA19-9. Moreover, we identified specific subsets of FAP+ and podoplanin+/cadherin-11+ CAFs enriched in patients with negative prognosis.

The present study provides new general insights into the complexity of the PDAC microenvironment by defining phenotypic heterogeneities and spatial distributions of CAFs, thus suggesting different functions of their subtypes in the PDAC microenvironment.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, characterized by its aggressive progression and dismal prognosis. Advances in epigenetic profiling, specifically DNA methylation analysis, have significantly deepened our understanding of PDAC pathogenesis. This review synthesizes findings from recent genome-wide DNA methylation studies, which have delineated a complex DNA methylation landscape differentiating between normal and cancerous pancreatic tissues, as well as across various stages and molecular subtypes of PDAC. These studies identified specific differentially methylated regions (DMRs) that not only enhance our grasp of the epigenetic drivers of PDAC but also offer potential biomarkers for early diagnosis and prognosis, enabling the customization of therapeutic approaches. The review further explores how DNA methylation profiling could facilitate the development of subtype-tailored therapies, potentially improving treatment outcomes based on precise molecular characterizations. Overall, leveraging DNA methylation alterations as functional biomarkers holds promise for advancing our understanding of disease progression and refining PDAC management strategies, which could lead to improved patient outcomes and a deeper comprehension of the disease's underlying biological mechanisms.

A rise in blood glucose is an early warning sign of underlying pancreatic cancer (PC) and may be an indicator of genetic events in PC progression. However, there is still a lack of mechanistic research on pancreatic cancer-associated new-onset diabetes (PCAND). In the present study, we identified a gene SRI, which possesses a SNP with the potential to distinguish PCAND and Type 2 diabetes mellitus (T2DM), by machine learning on the basis of the UK Biobank database. In vitro and in vivo, sorcin overexpression induced pancreatic β-cell dysfunction. Sorcin can form a positive feedback loop with STAT3 to increase the transcription of serpin E1 and CCL5, which may directly induce β-cell dysfunction. In 88 biopsies, the expression of sorcin was elevated in PC tissues, especially in PCAND samples. Furthermore, plasma serpin E1 levels are higher in peripheral blood samples from PCAND patients than in those from T2DM patients. In conclusion, sorcin may be the key driver in PCAND, and further study on the sorcin-STAT3-serpin E1/CCL5 signaling axis may help us better understand the pathogenesis of PCAND and identify potential biomarkers.

In attempts to establish sophisticated models to reproduce the process of acquired drug resistance, we transformed normal human pancreatic ductal epithelial cells by introducing genes for multiple cellular factors. We also created isogenic gemcitabine-sensitive and -resistant models by short- and long-term gemcitabine treatment, respectively. These models demonstrated differences in drug resistance in vivo, but not in vitro. Gemcitabine treatment also induced squamous transdifferentiation in xenografts in mice. The transcription factor p63 was identified as a possible resistance-determining factor but was unlikely to be solely responsible for the resistance to gemcitabine. This system would prove useful to discover novel molecular targets to overcome chemotherapy resistance, by allowing the evaluation of molecules of interest in xenograft models after in vitro genetic ablation.

Background: Oncogenic mutations in the KRAS gene are detected in >90% of pancreatic cancers (PC). In genetically engineered mouse models of PC, oncogenic KRAS drives the formation of precursor lesions and their progression to invasive PC. The Yes-associated Protein (YAP) is a transcriptional coactivator required for transformation by the RAS oncogenes and the development of PC. In Ras-driven tumors, YAP can also substitute for oncogenic KRAS to drive tumor survival after the repression of the oncogene. Ras oncoproteins exert their transforming properties through their downstream effectors, including the PI3K kinase, Rac1 GTPase, and MAPK pathways. Methods: To identify Ras effectors that regulate YAP, YAP levels were measured in PC cells exposed to inhibitors of oncogenic K-Ras and its effectors. Results: In PC cells, the inhibition of Rac1 leads to a time-dependent decline in YAP protein, which could be blocked by proteosome inhibitor MG132. This YAP degradation after Rac1 inhibition was observed in a range of cell lines using different Rac1 inhibitors, Rac1 siRNA, or expression of dominant negative Rac1T17N mutant. Several E3 ubiquitin ligases, including SCFβTrCP, regulate YAP protein stability. To be recognized by this ligase, the βTrCP degron of YAP (amino acid 383-388) requires its phosphorylation by casein kinase 1 at Ser384 and Ser387, but these events must first be primed by the phosphorylation of Ser381 by LATS1/2. Using Flag-tagged mutants of YAP, we show that YAP degradation after Rac1 inhibition requires the integrity of this degron and is blocked by the silencing of βTrCP1/2 and by the inhibition of casein kinase 1. Unexpectedly, YAP degradation after Rac1 inhibition was still observed after the silencing of LATS1/2 or in cells carrying a LATS1/2 double knockout. Conclusions: These results reveal Rac1 as an oncogenic KRAS effector that contributes to YAP stabilization in PC cells. They also show that this regulation of YAP by Rac1 requires the SCFβTrCP ligase but occurs independently of the LATS1/2 kinases.

Pancreatic ductal adenocarcinoma (PDAC) is associated with significant morbidity and mortality and is projected to be the second leading cause of cancer-related deaths by 2030. Mutations in KRAS are found in the vast majority of PDAC cases and plays an important role in the development of the disease. KRAS drives tumor cell proliferation and survival through activating the MAPK pathway to drive cell cycle progression and to lead to MYC-driven cellular programs. Moreover, activated KRAS promotes a protumorigenic microenvironment through forming a desmoplastic stroma and by impairing antitumor immunity. Secretion of granulocyte-macrophage colony-stimulating factor and recruitment of myeloid-derived suppressor cells and protumorigenic macrophages results in an immunosuppressive environment while secretion of secrete sonic hedgehog and TGFβ drive fibroblastic features characteristic of PDAC. Recent development of several small molecules to directly target KRAS marks an important milestone in precision medicine. Many molecules show promise in preclinical models of PDAC and in early phase clinical trials. In this review, we discuss the underlying cell intrinsic and extrinsic roles of KRAS in PDAC tumorigenesis, the pharmacologic development of KRAS inhibition, and therapeutic strategies to target KRAS in PDAC.

Pancreatic ductal adenocarcinoma (PDAC) poses significant clinical challenges, often presenting as unresectable with limited biopsy options. Here, we show that circulating tumor cells (CTCs) offer a promising alternative, serving as a "liquid biopsy" that enables the generation of in vitro 3D models and highly aggressive in vivo models for functional and molecular studies in advanced PDAC. Within the retrieved CTC pool (median 65 CTCs/5 mL), we identify a subset (median content 8.9%) of CXCR4+ CTCs displaying heightened stemness and metabolic traits, reminiscent of circulating cancer stem cells. Through comprehensive analysis, we elucidate the importance of CTC-derived models for identifying potential targets and guiding treatment strategies. Screening of stemness-targeting compounds identified stearoyl-coenzyme A desaturase (SCD1) as a promising target for advanced PDAC. These results underscore the pivotal role of CTC-derived models in uncovering therapeutic avenues and ultimately advancing personalized care in PDAC.