CDX2

CDX2 is a nuclear transcription factor essential for intestinal development and is relatively specific for intestinal epithelium. In IHC it serves as a key marker of gastrointestinal origin, strongly highlighting colorectal adenocarcinomas (commonly 86–100%) and aiding in distinguishing primary colorectal carcinoma from metastases to organs such as the bladder or lung. CDX2 also stains various intestinal‑type lesions including intestinal metaplasia in Barrett oesophagus, urachal and bladder glandular lesions, and selected adenocarcinomas of the stomach, small intestine, and extrahepatic bile ducts. While remaining negative in most non‑GI primary tumours. Its nuclear staining pattern makes it valuable in IHC panels evaluating tumours of uncertain origin, particularly when gastrointestinal differentiation is considered (1-2).

Recommended Controls

Criteria for acceptable staining is a nuclear staining pattern. Recommended control to include pancreas, colon and/or colon tumour. Normal lung or tonsil as a negative control. In the pancreas all ductal cells must express weak to moderate distinct nuclear staining, while the colon will express strong nuclear staining in the tumour cells as well as in the glandular epithelial cells.

Expected staining pattern

Colon adenocarcinoma 1

Colon adenocarcinoma 2

Normal colon

Disclaimer

These methods are intended as a guide only. Laboratories that wish to implement these methods should perform internal validation/verification prior to use. The RCPAQAP does not make any claim or warranty for the accuracy or performance of these methods.