KRAS and cholangiocarcinoma: When combined with Kras<sup>G12D</sup> mutation, Pbrm1 KO/Kras<sup>G12D</sup> mice had shorter survival and were more likely to develop cholangiocarcinomas, whereas Pbrm1 wild type/Kras<sup>G12D</sup> mice predominantly developed hepatocellular neoplasms.