Cdx2 was expressed in normal colorectal epithelium, in primary colorectal adenocarcinomas (20/20 cases), in secondary adenocarcinomas of colorectal (3/3) and gastric (3/4) origin, and in metastatic ovarian mucinous adenocarcinomas (2/2).
Since goblet cell-type MC strongly stains with CDX2, MUC2, and CK20, differential diagnosis with metastatic colorectal carcinoma is very challenging and requires appropriate clinical correlation.
The cytokeratin, mucin core protein, CDX2, Ki-67 and p53 expression patterns are identical in the xenograft and resected tumour and are consistent with the expected pattern of protein expression for mucinous adenocarcinoma of the appendix.