The results of our present study demonstrate that AICAr induces differentiation in a subset of non-APL AML blasts isolated from bone marrow of patients suffering from AML, and these effects do not correlate with FAB classification or mutational status of FLT3 or NPM1, but correlate with sensitivity to well-known, potent DHODH inhibitor. The gene discussed is NPM1; the disease is acute promyelocytic leukemia.