PIK3CA and cancer: Recently, mutation of a novel oncogene, PIK3CA, was discovered in multiple human epithelial cancers, including endometrial carcinoma (Oda et al, 2005; Hayes et al, 2006; Velasco et al, 2006); this oncogene encodes the catalytic p110α subunit of PI3K in various cancers (Samuels et al, 2004).