CEACAM5 and colorectal cancer: The role of carcinoembryonic antigen (CEA) in the production of liver metastases in colorectal cancer has been described in a recent paper by Lee and Lee3; CEA produced by colorectal cancers travels via the portal vein to the liver (once venous invasion of the primary tumour has occurred) and binds to CEA receptors within Kupffer cells of the liver.