IGF1R and intrahepatic cholangiocarcinoma: Intriguingly, in human colon samples from both normal and HSCR patients, KitlowCD34+Igf1r+ candidate ‘ICC progenitors’ were identified at a frequency of 0.7% of total cells [61] (similar to the KitlowCD34+Igf1r+ candidate ‘ICC progenitors’ identified in the mouse stomach [38]).