Primary ovarian endometrioid adenocarcinomas almost always exhibit diffuse positivity for CK7 and CA 125, while CK20, carcinoembryonic antigen (CEA), and CDX2 are usually negative [58, 63]; the converse immunophenotype (CK20+, CEA+, CDX2+, CK7−, and CA 125−) is observed in mCRC [38]. This evidence concerns the gene CEACAM5 and ovarian endometrioid adenocarcinoma.