PIK3CA and breast cancer: Despite many studies exploring Bcl-2 family proteins in breast cancer, most of the current literature has focused on the role of the antiapoptotic protein Mcl-1 (32, 47) in examining the efficacy of combination therapies using BH3 mimetics with other targeted agents such as NVP-BEZ235, everolimus (RAD001), and other pharmacologic inhibitors that target mTOR or PI3K signaling (23, 32, 43, 57).