PIK3CA and endometrial cancer: The central role of PI3K activation in tumor cell biology has prompted an effort to target PI3K and/or downstream kinases such as AKT and mammalian target of rapamycin (mTOR) in endometrial cancers where mutations in PIK3CA have been reported at high frequency in both Type I and Type II tumors (Pavlidou and Vlahos, 2014).