Gallbladder cancer (GBC) is an aggressive malignancy with a poor prognosis, often diagnosed at advanced stages due to subtle early symptoms. Recent studies have provided a comprehensive view of GBC's genetic and mutational landscape, uncovering crucial pathways involved in its pathogenesis. Environmental exposures, particularly to heavy metals, have been linked to elevated GBC risk. Established signaling pathways, including hormonal, apoptotic, metabolic, inflammatory, and DNA damage repair pathways, are integral to GBC progression, and evidence points to the involvement of specific germline and somatic mutations in its development. Key mutations in genes such as KRAS, TP53, IDH1/2, ERBB, PIK3CA, MET, MYC, BRAF, MGMT, CDKN2A and p16 have been identified as contributors to tumorigenesis, with additional alterations including chromosomal aberrations and epigenetic modifications. These molecular insights reveal several potential therapeutic targets that could address the limited treatment options for GBC. Promising therapeutic avenues under investigation include immune checkpoint inhibitors, tyrosine kinase inhibitors, tumor necrosis factor-related apoptosis-inducing ligands (TRAIL), and phytochemicals. Numerous clinical trials are assessing the efficacy of these targeted therapies. This review provides a detailed examination of GBC's genetic and mutational underpinnings, highlighting critical pathways and emerging therapeutic strategies. We discuss the implications of germline and somatic mutations for early detection and individualized treatment, aiming to bridge current knowledge gaps. By advancing our understanding of GBC's molecular profile, we hope to enhance diagnostic accuracy and improve treatment outcomes, ultimately paving the way for precision medicine approaches in managing GBC.

The incidence of biliary tract cancer is increasing in developed countries and is generating renewed interest in the scientific community due to the evidence of a high percentage (approximately 40%) of potentially targetable molecular alterations. However, to date, patient selection and the development of therapeutic approaches remain challenging due to the need for accurate diagnosis, adequate sampling, a specialized team for molecular analysis, centralization of patients in high-volume centers capable of supporting the high cost of these methods, and the feasibility of clinical studies on diseases with aggressive onset and poor prognosis. In this article, we would like to provide a detailed overview of the necessary tools for diagnostic framing and the various therapeutic scenarios being investigated concerning the most frequently detected molecular alterations.

There are limited conventional chemotherapy options for biliary tract cancers (BTCs), a heterogenous group of lethal, rare malignancies. The receptor tyrosine kinase (RTK) is closely associated with the progression of human malignancies through the regulation of cell cycle. Overexpression or amplification of RTKs has been investigated as a potential biomarker and therapeutic target in BTC; herein, we investigate the value of such interventions.

Overexpression of RTK proteins was examined by immunohistochemistry in 193 BTC samples, of which 137 were gallbladder carcinoma, 29 were perihilar cholangiocarcinoma, and 27 were intrahepatic cholangiocarcinoma. Silver in situ hybridization of MET and HER2 was performed to assess gene amplification.

In the entire cancer group, gallbladder, perihilar, and intrahepatic, MET amplification rates were 15.7%, 19.0%, 3.4%, and 14.8%, respectively, and of HER2 amplification rates were 22.4%, 27.2%, 17.2%, and 3.7%, respectively. MET and HER2 protein expressions were significantly correlated with their gene amplification status. RTKs were significantly associated with adverse clinicopathologic features such as advanced pT category and lymph node metastasis. Overall survival was significantly shorter in MET-amplified (P = .024) and EGFR-overexpressed cases (P = .045). Recurrence-free survival was significantly correlated with HER2-amplified (P = .038) and EGFR-overexpressed cases (P = .046) in all patient groups. Overall and recurrence-free survival were significantly shorter in patients who were double positive for HER2 and EGFR.

Our data suggested that MET, HER2, and EGFR might be potential therapeutic targets and that their co-expression is a strong prognostic factor for BTCs.

Colorectal cancer (CRC) is the third most common cancer and the second most common cause of cancer-related mortality worldwide. Mesenchymal-epithelial transition factor (MET) gene participates in multiple tumor biology and shows clinical potential for pharmacological manipulation in tumor treatment. MET amplification has been reported in CRC, but data are very limited. Investigating pathological values of MET in CRC may provide new therapeutic and genetic screening options in future clinical practice.

To determine the pathological significance of MET amplification in CRC and to propose a feasible screening strategy.

A number of 205 newly diagnosed CRC patients undergoing surgical resection without any preoperative therapy at Shenzhen Cancer Hospital of Chinese Academy of Medical Sciences were recruited. All patients were without RAS/RAF mutation or microsatellite instability-high. MET amplification and c-MET protein expression were analyzed using fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC), respectively. Correlations between MET aberration and pathological features were detected using the chi-squared test. Progression free survival (PFS) during the two-year follow-up was detected using the Kaplan-Meier method and log rank test. The results of MET FISH and IHC were compared using one-way ANOVA.

Polysomy-induced MET amplification was observed in 14.4% of cases, and focal MET amplification was not detected. Polysomy-induced MET amplification was associated with a higher frequency of lymph node metastasis (LNM) (P < 0.001) and higher tumor budding grade (P = 0.02). In the survival analysis, significant difference was detected between patients with amplified- and non-amplified MET in a two-year follow-up after the first diagnosis (P = 0.001). C-MET scores of 0, 1+, 2+, and 3+ were observed in 1.4%, 24.9%, 54.7%, and 19.0% of tumors, respectively. C-MET overexpression correlated with higher frequency of LNM (P = 0.002), but no significant difference of PFS was detected between patients with different protein levels. In terms of concordance between MET FISH and IHC results, MET copy number showed no difference in c-MET IHC 0/1+ (3.35 ± 0.18), 2+ (3.29 ± 0.11) and 3+ (3.58 ± 0.22) cohorts, and the MET-to-CEP7 ratio showed no difference in three groups (1.09 ± 0.02, 1.10 ± 0.01, and 1.09 ± 0.03).

In CRC, focal MET amplification was a rare event. Polysomy-induced MET amplification correlated with adverse pathological characteristics and poor prognosis. IHC was a poor screening tool for MET amplification.

MET alterations, including MET exon 14 skipping variants, MET amplification, MET overexpression, and MET fusion, play pivotal roles in primary tumorigenesis and acquired resistance to targeted therapies, especially EGFR tyrosine kinase inhibitors. They represent important diagnostic, prognostic, and predictive biomarkers in many solid tumor types. However, the detection of MET alterations is challenging due to the complexity of MET alterations and the diversity of platform technologies. Therefore, techniques with high sensitivity, specificity, and reliable molecular detection accuracy are needed to overcome such hindrances and aid in biomarker-guided therapies. The current review emphasizes the role of MET alterations as oncogenic drivers in a variety of cancers and their involvement in the development of resistance to targeted therapies. Moreover, our review provides an overview of and recommendations on the selection of various cross-platform technologies for the detection of MET exon 14 skipping variants, MET amplification, MET overexpression, and MET fusion. Furthermore, challenges and hurdles underlying these common detection platforms are discussed.

Biliary tract cancers (BTCs), for their low incidence, have been often considered together. Gallbladder cancer (GBC) is the most common biliary tract malignancy, characterized by late diagnosis and poor prognosis, and although it is considered a rare tumor in western countries, other areas of the world show considerable incidence rates. In 2010, results from the large phase III ABC-02 clinical trial on GBC identified the gemcitabine and cisplatin combination as the most effective first-line regimen for both GBC and other BTCs. Since then, various systemic therapies have proven active in BTCs in both first- and second-line settings. Molecular profiling has highlighted important genetic differences between GBC and other BTCs, opening new ways for targeted therapy in advanced disease where standard chemotherapies show marginal benefit. Genome-wide data analysis have shown that GBC molecular landscape offer possible strategies for precision medicine approaches, and a better molecular understanding of the GBC is needed to better stratify patients for treatment. In this review, we discuss the molecular targetable agents for GBC, including the results that emerged by clinical trials exploring new treatment strategies.

Gallbladder cancer (GBC) is a highly invasive disease and the most prevalent malignancy of the biliary system. Patients with GBC are commonly diagnosed at a late stage and have an unfavorable prognosis. Palliative chemotherapy has been the standard care for recurrent or metastatic disease in the past decades. Recently, several targeted therapies have been investigated in advanced biliary tract cancer (BTC) including inhibitors of genes or pathways such as FGFR2 fusions or rearrangements, IDH1 mutations, and NTRK gene fusions. Also, several clinical studies involving molecular stratification have been performed in defined patient groups, for example, BRAF V600E and HER2. Mesenchymal epithelial transition(MET)encodes a tyrosine kinase receptor and its ligand hepatocyte growth factor is a proto-oncogene. Targeting the MET signaling pathway is an effective strategy in numerous cancer types. However, the poor efficacy of MET inhibitors has been demonstrated in several phase II studies, but currently no reports have explained the potential mechanisms of resistance to MET inhibitors in BTC. In this article, we report a case of metastatic GBC with MET amplification that exhibited a rapid response to crizotinib after the failure of two lines of chemotherapy. After the patient had progressed and discontinued crizotinib, cabozantinib was introduced. Analysis of circulating tumor DNA (ctDNA) by next-generation sequencing (NGS) indicated a loss of MET amplification status. To our knowledge, this is the first case study demonstrating the use of NGS in ctDNA to monitor the development of acquired resistance during anti-MET treatment in GBC.

Gallbladder cancer (GBC) is the most common form of biliary tract malignancy with a dismal prognosis. A poor outcome in patients with GBC is related to the aggressive nature of the tumor, delayed diagnosis, and a lack of reliable biomarkers and effective treatment. Therefore, early diagnosis and accurate disease assessment are crucial to prolonging the patient survival. Identification of novel prognostic and diagnostic biomarkers may help improve the early diagnostic rate and develop specific targeted treatments for patients with GBC. We herein review the novel biomarkers that may be associated with the diagnosis and prognosis in GBC and their potential clinical significance in the management of GBC.

MET amplification has been associated with shorter survival in cancer patients and thought to represent one of two major mechanisms for developing resistance to therapy with EGFR inhibitors. We retrospectively studied 99 patients who had non-small cell lung cancer (NSCLC) and had at least two FISH analyses for MET/CEP7 at different time points during the course of disease. Four (4%) patients showed MET amplification in the initial diagnostic biopsy, and 16 (16%) patients acquired MET amplification in the follow-up biopsy specimens. Acquired MET amplification was highly associated with EGFR inhibitor treatment. Except for EGFR and TP53 mutations, other gene mutations were rare in the patients with MET amplification. Patients with acquired MET amplification showed no significant survival difference comparing to the patients who did not show MET amplification.

Gallbladder cancer (GBC) is rare, but is the most malignant type of biliary tract tumor. Unfortunately, only a small population of cancer patients is acceptable for the surgical resection, the current effective regimen; thus, the high mortality rate has been static for decades. To substantially circumvent the stagnant scenario, a number of therapeutic approaches owing to the creation of advanced technologic measures (e.g., next-generation sequencing, transcriptomics, proteomics) have been intensively innovated, which include targeted therapy, immunotherapy, and nanoparticle-based delivery systems. In the current review, we primarily focus on the targeted therapy capable of specifically inhibiting individual key molecules that govern aberrant signaling cascades in GBC. Global clinical trials of targeted therapy in GBC are updated and may offer great value for novel pathologic and therapeutic insights of this deadly disease, ultimately improving the efficacy of treatment.

Circular RNAs (circRNAs) are a type of endogenous non‑coding RNAs that are connected at the 3' and 5' ends by exon or intron cyclization, which forms a covalently closed loop. They are stable, well conserved, exhibit specific expression in mammalian cells and can function as microRNA (miRNA or miR) sponges to regulate the target genes of miRNAs, which influences biological processes. Such as tumor proliferation, invasion, metastasis, apoptosis and tumor stage. circRNAs represent promising candidates for clinical diagnosis and treatment. In the present review, the biogenesis, classification and functions of circRNAs in tumors are briefly summarized and discussed. In addition, the participation of circRNAs in signal transduction pathways regulating gastrointestinal cancer cellular functions is highlighted.

Biliary tract carcinomas are divided into intrahepatic, perihilar, distal extrahepatic cholangiocarcinomas, and gallbladder adenocarcinomas. Therapies targeting ROS1, ALK, MET, and HER2 alterations are currently evaluated in clinical trials. We assessed ROS1 and ALK translocations/amplifications as well as MET and HER2 amplifications for each tumor subtype by fluorescent in situ hybridization (FISH) and immunohistochemistry (IHC) in 73 intrahepatic, 40 perihilar bile duct, 36 distal extrahepatic cholangiocarcinomas, and 45 gallbladder adenocarcinomas (n = 194). By FISH, we detected targetable alterations in 5.2% of cases (n = 10): HER2 and MET amplifications were found in 4.1% (n = 8) and 1.0% (n = 2), respectively. The HER2-amplified cases were mostly gallbladder adenocarcinomas (n = 5). The MET- and HER2-amplified cases were all positive by IHC. Fourteen cases without MET amplification were positive by IHC, whereas HER2 over-expression was detected by IHC only in HER2-amplified cases. We detected no ALK or ROS1 translocation or amplification. Several alterations were consistent with aneuploidy: 24 cases showed only one copy of ROS1 gene, 4 cases displayed a profile of chromosomal instability, and an over-representation of centromeric alpha-satellite sequences was found in five cases. We confirm a relatively high rate of HER2 amplifications in gallbladder adenocarcinomas and the efficacy of IHC to screen these cases. Our results also suggest the value of IHC to screen MET amplification. Contrary to initial publications, ROS1 rearrangements seem to be very rare in biliary tract adenocarcinomas. We confirm a relatively high frequency of aneuploidy and chromosomal instability and reveal the over-representation of centromeric alpha-satellite sequences in intrahepatic cholangiocarcinomas.