KRT7 and cancer: Moreover, the visualization of tumor cells from the colon mucosa (positive for CDX2 and CK20) may help to differentiate between metastatic colon cancer, showing intrabiliary growth, and other cancers, such as primitive biliary neoplasias (always positive for CK7, like nontumoral bile ducts) or hepatocellular carcinoma (positive for glypican-3, GPC3) with bile duct invasion [16,18,19].