CDX-2

Synonyms: CDX2

by Jan Klos

Background

It is a transcription factor encoded by the CDX2 gene a member of the caudal-related homeobox transcription factor family involved in embryogenesis in regulation of proliferation and differentiation of intestinal epithelial cells. It is shown to decrease the cellular replication and increase the expression of genes involved in cellular differentiation.

Staining in normal tissues: the antigen is strongly expressed in majority of epithelial cells of colon and rectum, appendix, small intestine and less strongly in pancreatic interacinar ducts. Expression in minority of cells is found in pancreatic intermediate to large ducts.

Staining in tumors: Positive in majority of cases are adenocarcinomas of small intestine, intestinal type of adenocarcinoma of sinonasal region or lung, ovarian mucinous adenocarcinoma, bladder adenocarcinoma, mucinous carcinoma of urachus, intestinal type endocervical adenocarcinoma, and other tumors with intestinal differentiation. Expression in more than 50% of nuclei may be exceptionally found in some tumors of non-intestinal origin, but in the intestinal tumors the majority of cells are stained. Positive often heterogeneous staining is seen in minority of cases adenocarcinoma of pancreatic ducts, extrahepatic biliary tract, stomach and esophagus, endometrioid adenocarcinoma both in endometrium and ovary (positive in morula formations). Midgut carcinoids and neuroendocrine carcinomas are mostly positive, while those originating from the foregut and hindgut are mostly negative. Neuroendocrine tumors of pancreas and other organs are often negative. Yolk sac tumor and some other tumors may occasionally express CDX-2. Aberrant expression of CDX2 is reported in more than 85% of the human patients with acute myeloid leukemia (AML).

Staining pattern is nuclear.

Control tissue: pancreas (ductal epithelial cells).

Application

  • Confirmation of gastrointestinal differentiation, especially colorectal especially in the setting of unknown primary tumor.

Selected references