BRCA2 and breast cancer: At a monogene level, according to the old concept of “one-gene/one-protein/one-function” [4] at a time that considered a gene function in isolation from its interacting partners, the inherited mutations in BRCA1 and BRCA2, the strongest susceptibility tumor suppressor genes for BC, among other cancers [33], have longtime been considered as the main genetic factors in BC [34].