Subsequently, IDH mutations have been implicated in a variety of other tumor types, including sinonasal undifferentiated carcinoma (occurring in 49–82% of cases), angioimmunoblastic T-cell lymphoma (32% of cases), acute myeloid leukemia (AML; in 20%), cholangiocarcinoma (~20%), and at lower frequencies in other rare tumor types [8,9]. This evidence concerns the gene IDH1 and cholangiocarcinoma.