In conclusion, tumor tissue biomarkers may be of particular value for resected CCA, as they can have both prognostic (e.g., KRAS, TP53), as well as predictive (e.g., IDH1/2, FGFR2) implications by predicting the individual patient’s prognosis and response to targeted therapies. The gene discussed is IDH1; the disease is cholangiocarcinoma.