BRCA1 and BRCA2 genes encode proteins that have important roles in DNA repair and act as tumor suppressors. Though the sequence and structure of the proteins produced by BRCA1 and BRCA2 are different, they have similar biological activities. Both BRCA gene products are reported to interact with the RAD51 protein, which is essential for DNA repair through homologous recombination. BRCA gene mutations are associated with an increased risk of solid tumors. Their ubiquitously expressed protein products are involved in essential cellular functions. The defect caused by BRCA gene mutations might be leveraged to develop new targeted cancer treatments. This chapter outlines that BRCA1 and BRCA2 have unique roles in the pathways leading to DNA double-strand break repair and clinical findings show that BRCA genes play a crucial role in a variety of biological processes.