ARG1 and neoplasm: The tumor cells of int-CAs showed coexpression of hepatocytic (HepPar1, arginase-1, or α-fetoprotein) and biliary markers (cytokeratin 19 or carcinoembryonic antigen), and at least 1 of the hepatocyte markers and 1 of the biliary markers were detected by immunohistochemical stain (Figure 1A).