Disclosed herein are methods of treating cholangiocarcinoma in a patient comprising: evaluating a biological sample from the patient for the presence of one or more FGFR mutants including at least the FGFR2 SNP C383R; and treating the patient with an FGFR inhibitor if one or more FGFR mutants including at least the FGFR2 SNP C383R are present in the sample.