Studies show CDX2 is a sensitive marker for colonic carcinoma metastatic to the ovary and is more specific than CK20 as it is not expressed by serous and endometrioid carcinomas. CDX2 is also expressed in mucinous ovarian carcinomas. CDX2 is reported to be advantageous over CK20 for distinguishing primary ovarian tumors from metastases of upper gastrointestinal tract origin. Cytokeratin 7 shows expression in primary ovarian tumors and metastases of upper gastrointestinal tract origin. A CDX2 and CK7 panel may help in distinguishing colonic carcinomas metastatic to the ovaries from primary ovarian carcinomas.