Thus, when evaluating IDH2 protein expression and its possible impact on cellular mechanisms, both mutant and wt IDH2 protein must be taken into consideration in order to gain insight into the presumed pathogenic association of IDH2 in myeloid and lymphoid disorders in general, and in MPN-AITL patients in particular. The gene discussed is IDH2; the disease is angioimmunoblastic T-cell lymphoma.