PIK3CA and ovarian endometrioid adenocarcinoma: According to recent evidence from microarray gene expression profiling, endometrioid ovarian cancer shows altered KRAS, BRAF, PIK3CA, CTNNB1, ARID1A and PPP2R1A expression, with a peculiar molecular profile different from high-grade serous cancers, which have a mesenchymal cell type, characterized by overexpression of N-cadherin and P-cadherin and low expression of differentiation markers, including CA125 and MUC1 [18].