KRT19 and intrahepatic cholangiocarcinoma: AAI‐induced neoplastic nodules in Arid1af/f and Arid1aLKO mice were primarily HCC (n = 44), with a small number of combined hepatocellular and intrahepatic cholangiocarcinoma (cHCC‐ICC) (n = 4), identified by immunohistochemistry using glutamine synthetase (GS) and cytokeratin (Ck19) as markers of HCC and ICC, respectively (Figure 1D,E).