NPM1 and acute myeloid leukemia: In AML patients, it is possible that IDH1R132, IDH2R140, and IDH2R172 mutations represent molecular or clinically distinctive subgroups, with IDH1R132 and IDH2R140 more frequently accompanied by normal cytogenetics and NPM1 mutation, whereas IDH2R172 is frequently the only mutation detected and portends a poor prognosis.