By contrast, 5 AML cases harboring MLL re-arrangements and 5 AML cases with inv(16) displayed a FAB-M4/M5 morphology and up-regulated IDO1 upon treatment with IFN-γ (p=0.0065 by the Fisher's exact test, compared with children with CN leukemia). The gene discussed is KMT2A; the disease is acute myeloid leukemia.