KDR and cancer: Apatinib is a novel, small molecule, selective vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase inhibitor and has been confirmed to be effective in various advanced cancers including gastric cancer, hepatocellular carcinoma, non-small cell lung cancer, and breast cancer.41,42,43,44 In biliary tract cancer, apatinib is also in the clinical exploration stage and has not yet been listed as standard treatment for iCCA in guidelines.45,46,47