ARID1A and uterine corpus endometrial carcinoma: We next directly tested this possibility by comparing copy number variations in ARID1A wild-type and mutated uterine corpus endometrial carcinoma, stomach adenocarcinoma, and colon adenocarcinoma in the TCGA dataset because these cancer types display high-ARID1A mutation frequencies1 and the TCGA does not have OCCCs.