KITLG and intrahepatic cholangiocarcinoma: The work of Ordog et al., suggests that (1) maintenance and survival of ICC requires insulin-like growth factor-I (IGF-1)/insulin and membrane-bound SCF; (2) IGF-1 promotes differentiation of ICC precursors to mature ICC; and (3) soluble SCF expands ICC progenitors [11], [13], [18].