PIK3CA and breast cancer: Approximately 10% of BC cases correspond to hereditary factors with germline mutations in BRCA1, BRCA2, TP53, E-Cadherin, STK11, PTEN, ATM, and CHEK2 genes, while 90% of mammary tumors are adenocarcinomas with the presence of somatic mutations in high-penetrance genes such as PIK3CA, AKT1, SF3B1, GATA3, MLL3, CDH1, MAP3K1, NCOR1, MAP2K4, and MACF1 [5, 8–10].