PIK3CA activation is reported in 26–36% of endometrial carcinoma and may coexist with PTEN (15–27%) [7, 9, 12, 15, 20] and KRAS mutations [9, 15, 20] suggesting that the PIK3CA mutations cooperate with these alterations in malignant transformation [16]. This evidence concerns the gene PIK3CA and endometrial carcinoma.