All IHC stains will include a positive control tissue

• CDX2 is a specific and sensitive marker of normal and neoplastic intestinal epithelium, and thus is very useful in identifying a metastatic tumor of GI origin
• Loss of CDX2 expression has been observed in poorly differentiated MSI colorectal carcinomas; these tumors have undergone mutation of the CDX2 gene, and thus the tumors appear as CDX2 negative
• CDX2 can be used in a panel with CK7 and CK20, and will be extremely useful in colorectal tumors that show an aberrant CK7/CK20 profile (5-25% of cases), or in colorectal tumors that show only focal CK20 staining (can be a problem in small biopsies or cytologic specimens)

Submit a formalin-fixed, paraffin-embedded tissue

Formalin-fixed, paraffin-embedded (FFPE) tissue block

FFPE tissue section mounted on a charged, unstained slide

Ambient (preferred)

• Unlabeled/mislabeled block
• Insufficient tissue
• Slides broken beyond repair

Immunohistochemical staining and microscopic examination

If requested, an interpretive report will be provided

Specifications

• CDX2 is a homeobox gene necessary for intestinal organogenesis, and encodes for nuclear transcription factors involved in proliferation and differentiation of intestinal epithelial cells
• CDX2 is expressed in normal colonic epithelium, and in most colorectal adenocarcinomas (>95%)
• CDX2 expression is seen in epithelial cells from duodenum to rectum, including absorptive, goblet, endocrine, and Paneth cells (and is seen in intestinal metaplastic cells of stomach)
• CDX2 staining has also been identified in tumors of gallbladder (60%), pancreatic (60%), stomach (55%), and ovarian mucinous (64-100%) origin. Adenocarcinomas of the urinary bladder (2 of 2 cases; 100%) have also been shown to stain positive; rarely, CDX2 has been also reported in tumors from prostate and thyroid (papillary)
• CDX2 expression can also be seen in lung cancers (reported in lung adenocarcinomas and large cell carcinomas)

 
Staining pattern

• Nuclear based staining

References

1. Barbarexchi M, et al: CDX2 homeobox gene expression is a reliable marker of colorectal adenocarcinoma metastases to the lungs. Am J Surg Pathol 27 (2): 141-149, 2003.
2. Werling RW et al: CDX2, a highly sensitive and specific marker of adenocarcinomas of intestinal origin; an immunohistochemical survey of 476 primary and metastatic carcinomas. Am J Surg Pathol 27(3): 303-310, 2003.
3. Mazziotta RM et al: CDX2 immunostaining as a gastrointestinal marker: expression in lung carcinomas is a potential pitfall. Appl Immunohostochem Mol Morphol 2005 Mar; 13(1):55-60.