PIK3CA and endometrial carcinoma: Type I endometrial carcinoma shows mutations in K-RAS, PTEN, PIK3CA, and CTNNB1 (β-catenin) genes, whereas type II endometrial cancer has p53 changes, loss of heterozygosity, and other molecular modifications (p16, STK15, c-erb-B2, and E-cadherin).