CDX2 and colorectal carcinoma: The CDX2 protein demonstrates robust nuclear expression within non-neoplastic intestinal epithelial cells and is reliably identified in the vast majority of CRC histological subtypes (90–100%), including metastases originating from colorectal tissue, thereby functioning as an immunohistochemical marker for confirming or excluding intestinal origin in secondary tumors of unknown origin [9,31,34,36,40].