Studies conducted in both OCCC and in endometrial carcinoma have shown that ARID1A mutations are found in 50 and 30% of patients, respectively (2, 5, 9, 15, 49, 51) and that patients with tumors carrying ARID1A mutations have worse prognosis as compared with patients who do not. This evidence concerns the gene ARID1A and endometrial carcinoma.