BRCA1 and neoplasm: BRCA1 serves as a tumor suppressor to participate in many important biological processes including homologous recombination (HR) -mediated DNA damage repair, S and G2/M cell cycle checkpoint, chromatin remodeling, replication fork protection and transcriptional regulation6–12, and loss of these functions either by mutation or by reduction in protein level is believed to be responsible for the accumulation of genomic instability and even tumorigenesis.