Genetic and clinical characterization of multigene hereditary breast and ovarian cancer (HBOC) panels in Málaga (Spain).

Abstract

e22530 Background: Next Generation Sequencing (NGS) technologies have transformed hereditary breast and ovarian cancer (HBOC) testing process. Several multigene panels (MP) include from 10 to 100 candidate cancer susceptibility genes, but there is a debate about what genes should and should not be tested because of lack of actionability. Few studies have been reported about MP in Europe or Spanish cancer families and no studies in Andalusian population (southern Spain). Methods: We investigated a panel of 17 known genes of high/moderate-risk for HBOC in 938 clinically suspicious HBOC Andalusian families (SEOM 2015 criteria), tested from 2017 to 2019. Multigene panel including BRCA,1 BRCA2, CHEK2, PALB2, BRIP1, ATM, MLH1, MSH2, MSH6, PMS2, CDH1, NF1, PTEN, p53, STK11, RAD51C and RAD51D was performed. Results: We identified 130 patients who carried a high- or moderate-risk pathogenic variants: 61 in BRCA2 (47%), 30 in BRCA 1 (23%), 10 in CHEK2 (8%), 7 in ATM (5%), 7 in PALB2 (5%), 4 in RAD51 (3%), 4 in BRIP1 (3%), 4 in MSH6 (3%), 2 in MLH1 (1,5%) and 1 in MSH2. We detected 220 patients carry variants of uncertain significance (VUS), with a total of 248 VUS (some patients carried more than one VUS): 46 (19%) in ATM, 38 (15%) in BRCA 2, 28 (11%) in MSH6, 19 (8%) in PMS2, 17 (7%) in BRIP1, 16 (6%) in NF1, 14 (6%) in MSH2 and 12 (5%) in CDH1 and PALB2. The most frequent criteria in the entire cohort was “High-grade epithelial non-mucinous ovarian cancer”, reported in 243 cases (26%)”, whereas “Breast cancer (BC) diagnostic under 35” was the most frequent criteria between positives (48 cases (40%)). One case carried two pathogenic variants: BRCA2 and MUTYH. Conclusions: This is the first study reporting the mutational profile of MP gene testing in Andalusia. 70% of mutations were due to BRCA1 and 2 followed by far by CHEK2, ATM and PALB2. We also identified a large amount of VUS in BRCA2, ATM and MSH6. MP improve the diagnostic in andalusian HBOC patients.