The allelic ratio of FLT3-internal tandem duplication to wild-type FLT3 has been shown to correlate with clinical outcome, and a cutoff value of 0.5 was adopted by both the European Leukemia Net and National Comprehensive Cancer Network consensus guidelines to classify FLT3-internal tandem duplication as high and low allelic ratio categories and further risk stratify FLT3-internal tandem duplication-positive acute myeloid leukemia patients in the context of NPM1 and cytogenetic findings [10, 11]. This evidence concerns the gene NPM1 and acute myeloid leukemia.