FGFR2 and intrahepatic cholangiocarcinoma: To further characterize the change of mitochondrial fuel usage upon FGFR inhibition in FGFR2-fusion+ ICC, we performed the Agilent Seahorse XF Mito Fuel Flex test, which measures the rate of oxidation of different fuels by assessing the effect of specific metabolic inhibitors on mitochondrial respiration (Fig. 4a).