BRCA and PALB2 mutations in a cohort of male breast cancer with one bilateral case

Introduction: Male Breast Cancer (MBC) is a rare disease, about 1% of all breast cancers worldwide and less than 1% of cancers occurring in men. The bilateral male breast cancer (bMBC) is extremely rare. Germline mutations of BRCA1/BRCA2 genes are associated with a significantly increased risk of cancer in MBC; the role of PALB2 remains to be clarified. Our main goal was to provide contribution on characterization of BRCA1/BRCA2 and PALB2 mutations in MBC patients. Methods: We observed 28 MBC cases; one of them was a bMBC. Screening for BRCA1, BRCA2 and PALB2 genes was performed on all 28 MBC patients. Mutational analysis was extended to family members of mutated patients. Results: In our study, the MBC incidence was 5.2% and for bMBC was 3.6%. Mutation analysis showed pathogenic mutations in 11/28 (39.3%) patients; 2/28 (7.1%) displayed a mutation in BRCA1, 8/28 (28.6%) in BRCA2 and 1/28 (3.6%) in PALB2. Out of 11 mutated patients, one (9.1%) reported a double mutation in BRCA2. Personal history of other cancers was reported in 2/28 (7.1%) patients affected by bladder cancer. A first/second degree family history of breast/ovarian and other cancers occurred in 23/28 (82.1%) patients. Conclusion: Our findings indicate BRCA2 as the main MBC susceptibility gene and describe an increased risk of bMBC and bladder cancer in mutated patients. The identification of mutations in MBC susceptibility genes supports the usage of oncology prevention programs in affected patients and their relatives carrying the mutation.