PIK3CA and breast cancer: It has been reported that BEZ235, one of the dual PI3K/mTOR(phosphatidylinositol 3-kinase/mammalian target of rapamycin) inhibitors, has a potent inhibitory effect in numerous tumors such as breast cancer [3], hepatic carcinoma [4], ovarian carcinoma [5], prostate cancer [6], medulloblastoma [7], non-small cell lung cancer [8, 9], non-Hodgkin lymphoma [10, 11], liposarcoma [12], cholangiocarcinoma [13], leukemia [14], pancreatic cancer [15, 16] and nasopharyngeal carcinoma [17] in preclinical studies, especially in PIK3CA mutant subtypes.