Differential Profile of BRCA1 vs. BRCA2 Mutated Families: A Characterization of the Main Differences and Similarities in Patients.

The identification of families at-risk for hereditary breast cancer (BC) is important because affected individuals
present a much higher cancer risk than the general population. The aim of this study was to identify the most important
factors associated with the presence of a pathogenic BRCA1/BRCA2 mutation. Family history (FH), histopathological
and immunohistochemical characteristics were compared among BC women with pathogenic BRCA1/BRCA2 variants;
VUSs in BRCA1/BRCA2; BRCA1/BRCA2 WT and sporadic BC. The most significative differences observed concerned
the molecular subtype of the tumors, age at cancer diagnosis and FH of cancer. The presence of bilateral breast cancer
(BBC), number of BC cases and the presence of ovarian cancer (OC) increased (respectively) 5.797, 5.033 and 4.412
times the risk of being a BRCA1/BRCA2 mutation carrier. Besides, women with BRCA1 or BRCA2 mutations presented
different tumor and FH profiles. The main characteristics associated with a BRCA1 mutation were triple negativity
(OR: 17.31), BBC history (OR: 4.96) and occurrence of OC (OR: 4.32). There were no major discerning components
associated with BRCA2 mutations. Thus, we conclude that tumor pathology and FH of cancer might be considered
together at the time of genetic testing mainly in countries where access to genetic testing is still restricted.