Characterization of a rare variant (c.2635-2A>G) of the MSH2 gene in a family with Lynch syndrome

Abstract Introduction: Lynch syndrome is caused by germline mutations in one of the mismatch repair genes (MLH1, MSH2, MSH6, and PMS2) or in the EPCAM gene. Lynch syndrome is defined on the basis of clinical, pathological, and genetic findings. Accordingly, the identification of predisposing genes allows for accurate risk assessment and tailored screening protocols. Case Description: Here, we report a family case with three family members manifesting the Lynch syndrome phenotype, all of which harbor the rare variant c.2635-2A>G affecting the splice site consensus sequence of intron 15 of the MSH2 gene. This mutation was previously described only in one family with Lynch syndrome, in which mismatch repair protein expression in tumor tissues was not assessed. In this study, we report for the first time the molecular characterization of the MSH2 c.2635-2A>G variant through in silico prediction analysis, microsatellite instability, and mismatch repair protein expression experiments on tumor tissues of Lynch syndrome patients. The potential effect of the splice site variant was revealed by three splicing prediction bioinformatics tools, which suggested the generation of a new cryptic splicing site. The potential pathogenic role of this variant was also revealed by the presence of microsatellite instability and the absence of MSH2/MSH6 heterodimer protein expression in the tumor cells of cancer tissues of the affected family members. Conclusions: We provide compelling evidence in favor of the pathogenic role of the MSH2 variant c.2635-2A>G, which could induce an alteration of the canonical splice site and consequently an aberrant form of the protein product (MSH2)

Identification and Somatic Characterization of the Germline PTEN Promoter Variant rs34149102 in a Family with Gastrointestinal and Breast Tumors

Genetic variants located in non-coding regions can affect processes that regulate protein expression, functionally contributing to human disease. Germline heterozygous mutations in the non-coding region of the PTEN gene have been previously identified in patients with PTEN hamartoma tumor syndrome (PHTS) diagnosed with breast, thyroid, and/or endometrial cancer. In this study, we report a PTEN promoter variant (rs34149102 A allele) that was identified by direct sequencing in an Italian family with a history of gastroesophageal junction (GEJ) adenocarcinoma and breast cancer. In order to investigate the putative functional role of the rs34149102 A allele variant, we evaluated the status of PTEN alterations at the somatic level. We found that PTEN protein expression was absent in the GEJ adenocarcinoma tissue of the index case. Moreover, we detected the occurrence of copy number loss involving the PTEN rs34149102 major C allele in tumor tissue, revealing that the second allele was somatically inactivated. This variant is located within an active regulatory region of the PTEN core promoter, and in silico analysis suggests that it may affect the binding of the nuclear transcription factor MAZ and hence PTEN expression. Overall, these results reveal the functional role of the PTEN promoter rs34149102 A allele variant in the modulation of PTEN protein expression and highlight its contribution to hereditary cancer risk

Metastatic Secondary Anaplastic Meningioma

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Targeting Angiogenesis in the Era of Biliary Tract Cancer Immunotherapy: Biological Rationale, Clinical Implications, and Future Research Avenues

Although biliary tract cancers are traditionally considered rare in Western countries, their incidence and mortality rates are rising worldwide. A better knowledge of the genomic landscape of these tumor types has broadened the number of molecular targeted therapies, including angiogenesis inhibitors. The role of immune checkpoint inhibitors (ICIs) could potentially change the first-line therapeutic approach, but monotherapy with ICIs has shown disappointing results in CCA. Several clinical trials are evaluating combination strategies that include immunotherapy together with other anticancer agents with a synergistic activity. The tumor microenvironment (TME) composition plays a pivotal role in the prognosis of BTC patients. The accumulation of immunosuppressive cell types, such as tumor-associated macrophages (TAMs) and regulatory T-cells, together with the poor infiltration of cytotoxic CD8+ T-cells, is known to predispose to a poor prognosis owing to the establishment of resistance mechanisms. Likewise, angiogenesis is recognized as a major player in modulating the TME in an immunosuppressive manner. This is the mechanistic rationale for combination treatment schemes blocking both immunity and angiogenesis. In this scenario, this review aims to provide an overview of the most recent completed or ongoing clinical trials combining immunotherapy and angiogenesis inhibitors with/without a chemotherapy backbone

Characterization of a rare variant (c.2635-2A>G) of the MSH2

Abstract Introduction: Lynch syndrome is caused by germline mutations in one of the mismatch repair genes (MLH1, MSH2, MSH6, and PMS2) or in the EPCAM gene. Lynch syndrome is defined on the basis of clinical, pathological, and genetic findings. Accordingly, the identification of predisposing genes allows for accurate risk assessment and tailored screening protocols. Case Description: Here, we report a family case with three family members manifesting the Lynch syndrome phenotype, all of which harbor the rare variant c.2635-2A>G affecting the splice site consensus sequence of intron 15 of the MSH2 gene. This mutation was previously described only in one family with Lynch syndrome, in which mismatch repair protein expression in tumor tissues was not assessed. In this study, we report for the first time the molecular characterization of the MSH2 c.2635-2A>G variant through in silico prediction analysis, microsatellite instability, and mismatch repair protein expression experiments on tumor tissues of Lynch syndrome patients. The potential effect of the splice site variant was revealed by three splicing prediction bioinformatics tools, which suggested the generation of a new cryptic splicing site. The potential pathogenic role of this variant was also revealed by the presence of microsatellite instability and the absence of MSH2/MSH6 heterodimer protein expression in the tumor cells of cancer tissues of the affected family members. Conclusions: We provide compelling evidence in favor of the pathogenic role of the MSH2 variant c.2635-2A>G, which could induce an alteration of the canonical splice site and consequently an aberrant form of the protein product (MSH2)

The multiple combination of Paclitaxel, Ramucirumab and Elacridar reverses the paclitaxel mediated resistance in gastric cancer cell lines

Introduction: Paclitaxel (PTX) interferes with microtubule architecture by binding to b-tubulin, thereby blocking progression at the G2/M phase and inducing apoptosis. This study aimed to investigate molecular processes underlying PTXmediated resistance in gastric cancer (GC) cells. Methods: PTX-mediated resistance involves many processes, and in this work some of the factors involved in the resistance mechanism were identified by comparing two GC lines with PTX induced resistance to their sensitive counterparts. Results: Thus, the key feature of PTX-resistant cells was the overexpression of proangiogenic factors such as VEGFA, VEGFC, and Ang2, known to support tumor cell growth. A second relevant change detected in PTX-resistant lines was the elevated level of TUBbIII, a tubulin isoform that opposes microtubule stabilization. A third identified factor contributing to PTX-resistance was P-glycoprotein (P-gp), a transporter responsible for chemotherapy efflux from the cells, highly expressed in PTX-resistant lines. Discussion : These findings were in line with a greater sensitivity of resistant cells to treatment with both Ramucirumab and Elacridar. Ramucirumab significantly reduced the expression of angiogenic molecules and TUBbIII, while Elacridar restored the access of chemotherapy, recovering its anti-mitotic and proapoptotic effects. Finally, this study highlighted the role played by exosomes in spreading factors responsible for resistance in the tumor microenvironment

VEGFA Status as a Predictive Marker of Therapy Outcome in Metastatic Gastric Cancer Patients Following Ramucirumab-Based Treatment

Metastatic gastric cancer (mGC) often has a poor prognosis and may benefit from a few targeted therapies. Ramucirumab-based anti-angiogenic therapy targeting the VEGFR2 represents a milestone in the second-line treatment of mGC. Several studies on different cancers are focusing on the major VEGFR2 ligand status, meaning VEGFA gene copy number and protein overexpression, as a prognostic marker and predictor of response to anti-angiogenic therapy. Following this insight, our study aims to examine the role of VEGFA status as a predictive biomarker for the outcome of second-line therapy with Ramucirumab and paclitaxel in mGC patients. To this purpose, the copy number of the VEGFA gene, by fluorescence in situ hybridization experiments, and its expression in tumor tissue as well as the density of micro-vessels, by immunohistochemistry experiments, were assessed in samples derived from mGC patients. This analysis found that amplification of VEGFA concomitantly with VEGFA overexpression and overexpression of VEGFA with micro-vessels density are more represented in patients showing disease control during treatment with Ramucirumab. In addition, in the analyzed series, it was found that amplification was not always associated with overexpression of VEGFA, but overexpression of VEGFA correlates with high micro-vessel density. In conclusion, overexpression of VEGFA could emerge as a potential biomarker to predict the response to anti-angiogenic therapy

Basal and bevacizumab-based therapy-induced changes of lactate dehydrogenases and fibrinogen levels and clinical outcome of previously untreated metastatic colorectal cancer patients: A multicentric retrospective analysis

BACKGROUND: To assess the predictive role of lactate dehydrogenases (LDH) and fibrinogen (FBG) serum levels in metastatic colorectal cancer (mCRC) patients receiving a first-line bevacizumab-based therapy. OBJECTIVES: The aim of the present analysis was to retrospectively evaluate the role of basal and post-treatment LDH and FBG serum levels in predicting the clinical outcome of 139 mCRC patients receiving first-line chemotherapy in combination with bevacizumab. RESULTS: A statistically significant association between high pre-treatment LDH and FBG levels and progressive disease was observed with respect to low basal LDH and FBG patients. Furthermore, median progression-free survival was 7.3 versus 10.8 months and 7.3 versus 9.4 months for high and low LDH and FBG levels, respectively. Within the high LDH group, we observed a statistically significant reduction of LDH mean value compared with pre-treatment values in patients with objective response rate and stable disease. CONCLUSIONS: High LDH and FBG levels correlated with prognosis. A significant correlation between bevacizumab-based chemotherapy-induced reduction in LDH serum levels and response to treatment was observed within the high LDH group. These results, if confirmed in larger prospective studies, could be helpful for early identification of patients responsive to bevacizumab-based chemotherapy or candidate to more aggressive treatments

The Italian Rare Biliary tract Cancer initiative (IRaBiCa): A multicentric observational study of Gruppo Oncologico dell'Italia Meridionale (GOIM) in collaboration with Gruppo Italiano Colangiocarcinoma (GICO)

Introduction: About 90% of cholangiocarcinomas are adenocarcinomas with glandular or tubular structures lined by epithelial cells, with no bile production and with a variable degree of differentiation, arising in the background of desmoplastic stroma. The remaining 10% is represented by rarer histological variants of which there is little knowledge regarding the biological behavior, molecular characterization, and sensitivity to the various possible therapies, including molecular-based treatments. Such rare tumors are described only in case reports or small retrospective series because of their exclusion from clinical trials. This national initiative, here presented, aims to address the following knowledge gap: a) how much does histological diversity translate into clinical manifestation variety? b) are those chemotherapy regimens, recommended for conventional biliary tract cancers, potentially active in rare variants?Therefore, epidemiological, pathological, and clinical characterization of series of rare biliary histotypes/variants, for which therapeutic and follow-up data are available, will be collected. Methods: An Italian task force on rare tumors of the biliary tract (IRaBiCa) has been created, whose initiative is a multicenter retrospective study involving 34 Italian cancer centers.Clinical data from approximately 100 patients will be collected and analyzed. Continuous variables will be presented as median ± standard deviation, while categorical variables will be expressed in terms of frequency. Kaplan-Maier analyses will be used to compare disease free, progression free and overall survival, according to the different histotypes. Conclusions: We expect to gather novel data on rare histotypes of biliary tract cancer that will be useful to support their molecular and immunological characterization