At the same time, the study and development of PI3K inhibitors have achieved preliminary success: a number of PI3K inhibitors such as alpelisib (BYL719), duvelisib, copanlisib, and idelalisib have been approved for the targeted therapy of PIK3CA-mutant head and neck tumors, breast cancer, or lymphoma; besides, dactolisib (BEZ235, dual PI3K/mTOR inhibitor), PI-103, buparlisib (BKM120), and so on have been approved for the clinical trials of solid tumors. This evidence concerns the gene PIK3CA and breast cancer.