After being first recognized in a single case of colorectal carcinoma in 2007 [1], IDH mutations have been identified in various types of human malignancies including – among others – acute myeloid leukemia (AML), intrahepatic cholangiocarcinoma, chondrosarcoma, and thyroid carcinoma [2, 3, 4, 5]. Here, IDH2 is linked to acute myeloid leukemia.