KRT7 and cholangiocarcinoma: For example, oncofactors released by colon cancer cells would give metachronous metastases if uptaken and expressed by fibroblasts in the liver (CK7−/CK20+/CDX2+) or a second type of cancer such as a cholangiocarcinoma (upper gastrointestinal tract and CK7+/CK20−/CDX2−) if they were uptaken and expressed by epithelial liver cells22,35.