FBXW7 and ovarian serous adenocarcinoma: Notably, however, the mutation frequency of five genes [PIK3CA (Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Alpha), PIK3R1 (phosphoinositide-3-kinase regulatory subunit 1), PTEN (phosphatase and tensin homolog), PPP2R1A (protein phosphatase 2 scaffold subunit Aalpha) and FBXW7 (F-box and WD repeat domain containing 7)] was dramatically higher in USC as compared to serous ovarian cancer (Cancer Genome Atlas Research Network 2013).