NPM1 and acute myeloid leukemia: Similarly, AML patients with FLT3-ITD but no mutation in the 12th exon of NPM1 showed significantly favorable OS than those carrying the two mutations simultaneously (P = 0.010), but showed significantly shorter OS and DFS than carriers of the NPM1 mutations alone (P = 0.002; P = 0.001, respectively, Additional file 4: Figure S3E, F).