HCN4 and intrahepatic cholangiocarcinoma: By transfecting lentiviral vectors with exogenous gene hyperpolarization-activated cyclic nucleotide-gated (HCN4) modification, Sun et al. inefficiently induced the directional differentiation of USCs into ICC-LCs, resulting in a morphological alteration from “rice grain”-like cells to spindle-shaped cells with multiple branches, higher expression of the ICC surface marker c-Kit, and a visible automatic depolarization current.