Male breast cancer: No evidence for mosaic BRCA1 promoter methylation involvement.

Breast cancers (BC) are rare in men and are often caused by constitutional predisposing factors. In women, mosaic BRCA1 promoter methylations (MBPM) are frequent events, detected in 4-8% of healthy subjects. This constitutional epimutation increases risk of early-onset and triple-negative BC.

Mosaic promoter methylation contribution in hereditary breast/ovarian cancer pedigrees.

Purpose: Mosaic promoter methylation (meth) increases the risk of early-onset breast cancer, triple-negative breast cancer and ovarian cancer. As mosaic meth are believed to occur de novo, their role in family breast/ovarian cancer has not been assessed.

Patients: Blood-derived DNA from 20 unrelated affected cases from families with aggregation of breast/ovarian cancer, but with no germline pathogenic variants in /, or , were screened by methylation-sensitive high-resolution melting.

: a confirmed predisposing gene for adenomatous polyposis.

Background: The gene is part of the DNA mismatch repair system, but has never been shown to be involved in Lynch syndrome. A first report of four patients from two families, bearing biallelic germline variants, with a phenotype of attenuated colorectal adenomatous polyposis raised the question of its involvement in hereditary cancer predisposition. The patients' tumours exhibited elevated microsatellite alterations at selected tetranucleotide repeats (EMAST), a hallmark of deficiency.

Hereditary cancer predispositions: Comparison of multigene panel sequencing on fresh-frozen breast/ovarian tumor versus blood.

In breast or ovarian cancer (BC/OC) patients with evocative personal and/or family history, multigene panel sequencing is performed on blood to diagnose hereditary predispositions. Additionally, BRCA1/BRCA2 testing can be performed on tumor sample for therapeutic purpose. The accuracy of multigene panel tumor analysis on BC/OC to detect predisposing germline pathogenic variants (gPV) has not been precisely assessed.

AXIN2 germline testing in a French cohort validates pathogenic variants as a rare cause of predisposition to colorectal polyposis and cancer.

Only a few patients with germline AXIN2 variants and colorectal adenomatous polyposis or cancer have been described, raising questions about the actual contribution of this gene to colorectal cancer (CRC) susceptibility. To assess the clinical relevance for AXIN2 testing in patients suspected of genetic predisposition to CRC, we collected clinical and molecular data from the French Oncogenetics laboratories analyzing AXIN2 in this context. Between 2004 and June 2020, 10 different pathogenic/likely pathogenic AXIN2 variants were identified in 11 unrelated individuals.

Cancer Risks Associated With and Pathogenic Variants.

Purpose: To provide precise age-specific risk estimates of cancers other than female breast and ovarian cancers associated with pathogenic variants (PVs) in and for effective cancer risk management.

Methods: We used data from 3,184 and 2,157 families in the Consortium of Investigators of Modifiers of to estimate age-specific relative (RR) and absolute risks for 22 first primary cancer types adjusting for family ascertainment.

Results: PVs were associated with risks of male breast (RR = 4.

Classification of 101 BRCA1 and BRCA2 variants of uncertain significance by cosegregation study: A powerful approach.

Up to 80% of BRCA1 and BRCA2 genetic variants remain of uncertain clinical significance (VUSs). Only variants classified as pathogenic or likely pathogenic can guide breast and ovarian cancer prevention measures and treatment by PARP inhibitors. We report the first results of the ongoing French national COVAR (cosegregation variant) study, the aim of which is to classify BRCA1/2 VUSs.

Clinical implications of CTNNA1 germline mutations in asymptomatic carriers.

In 2017, we implemented CTNNA1 germline analysis in probands suspected of having hereditary diffuse gastric cancer. Here, we report the results from a retrospective series of 41 cases, including the identification of a new family with a CTNNA1 mutation and the first prophylactic total gastrectomy in an asymptomatic carrier after a normal upper endoscopy. Diffuse gastric cancer foci with loss of catenin alpha-1 expression were seen in the resected tissue, suggesting that CTNNA1 and CDH1 germline mutations behave in a similar manner.

Clinicopathologic Characteristics of Endometrial Cancer in Lynch Syndrome: A French Multicenter Study.

Background: Limited data exist on Lynch syndrome (LS)-related endometrial cancer (EC) features. Amsterdam criteria II, commonly used, have poor sensitivity for detection of LS, which is underdiagnosed.

Aim: The aim of this study was to describe the clinical and pathological features of LS-related EC among mutation-proven patients.