PIK3CA and breast cancer: A couple of pathogenic mutations were identified and were clinically relevant: namely BRCA1/2, PTEN and PIK3CA. Both BRCA1 and BRCA2 are well-known tumor suppressors while Poly (ADP-ribose) polymerase (PARP) inhibitors are FDA-approved for patients with germline BRCA1/2 mutant ovarian and breast cancers [31].