For ovarian and uterine endometrioid carcinomas, somatic mutation frequencies were similar at nine commonly mutated genes in these tissues, namely TP53, PTEN, PIK3CA, NF1, MYC, KRAS, CTNNB1, BRCA1, and ARID1A (Fig. 5A). Here, ARID1A is linked to endometrial endometrioid adenocarcinoma.