Clinicopathologic and genetic characterization of nonacute -mutated myeloid neoplasms.

-mutated myeloid neoplasms ( MNs) with <20% blood or bone marrow blasts are rare and have been previously shown in limited case series to exhibit an aggressive clinical course. We assembled the largest cohort of MN cases to date (n = 45) and compared it with MN (n = 95) and de novo acute myeloid leukemia (AML; n = 119) patients. Compared with MN, MN were associated with younger age ( = .007), a normal karyotype ( < .0001), more frequent mutations involving ( = .01) and ( = .03), and fewer involving ( = .003), ( = .0004), and ( = .02). Mutations involving or () ( = .007) and (internal tandem duplication, < .0001; noninternal tandem duplication, = .01) were less frequent in MN than in AML. In multivariable analyses performed in patients with myelodysplastic syndrome only, total mutation count (hazard ratio [HR], 1.3; = .05), mutation (HR, 3.6; = .02), mutation (HR, 5.2; = .01), and higher International Prognostic Scoring System-R score (HR, 1.7; = .0003) were independently associated with shorter overall survival, whereas stem cell transplant conferred a favorable effect (HR, 0.1; < .0001). These data suggest that MN are biologically distinct from MN. Similar to AML, patients with -mutated myelodysplastic syndrome may benefit from more intensive therapeutic regimens.