Dactolisib (BEZ235) is a dual PI3K/mTOR kinase inhibitor that has been investigated in preclinical, phase I, and II trials but has demonstrated poor efficacy and tolerability in advanced pancreatic neuroendocrine tumors, RCCs, prostate cancers, and advanced solid tumors [176,177,178,179]. This evidence concerns the gene PIK3CA and prostate cancer.