[Association of Next Generation Sequencing Based Genotypic Profiling with MICM Characteristics in NPM1 Mutated Acute...

To explain the clinicobiological heterogeneity of NPM1 mutated (NPM1^mut) acute myeloid leukemia (AML) by analyzing the association between next-generation sequencing (NGS) profiles and MICM characteristics in patients with this AML subtype.

Data of 238 NPM1^mut patients with available NGS information on 112 genes related to blood disease was collected, and χ² test and nonparametric test were used to analyze the distribution association between NGS-detecting mutations and conventional MICM parameters.

In entire NPM1^mut cohort, totaling 240 NPM1 mutation events were identified, of whom 10 (10/240, 4.2%) were missense mutations, which did not involve any W288 or W290 locus and were found exclusively in NPM1^mut/FLT3-ITD^- group. All but one of these missense mutations (9/10, 90%) were accompanied by AML subtype-defining recurrent cytogenetic or molecular abnormalities, of which 7 cases were in the low risk and 2 in the high risk. NPM1^mut occurred solely as an insertion/deletion (indel) type in the NPM1^mut/FLT3-ITD⁺ group. The incidence of favorable plus unfavorable karyotypes in NPM1^mut/FLT3-ITD^- group was higher than in NPM1^mut/FLT3-ITD⁺ group (6.4% vs. 0, P=0.031). The positive rates of CD34 and CD7 in NPM1^mut/FLT3-ITD⁺ group were significantly higher than in NPM1^mut/FLT3-ITD^- group (CD34: 47.9% vs. 20.6%, P<0.001; CD7: 61.5% vs. 29.9%, P<0.001). Logistic analysis showed that FLT3-ITD independently predicted for CD34⁺ and CD7⁺ [odds ratio (OR)=5.29, 95%CI: 2.64-10.60, P<0.001; OR=3.47, 95%CI: 1.79-6.73, P<0.001; respectively]. Ras-pathway mutations independently predicted for HLA-DR⁺ (OR=4.05, 95%CI: 1.70-9.63, P=0.002), and KRAS mutation for MPO^- (OR=0.18, 95%CI: 0.05-0.62, P=0.007). TET2/IDH1 mutations independently predicted for CD34^- and CD7^- (OR=0.26, 95%CI: 0.11-0.62, P=0.002; OR=0.30, 95%CI: 0.14-0.62, P=0.001; respectively), and MPO⁺ (OR=3.52, 95%CI: 1.48-8.38, P=0.004). DNMT3A-R882 independently predicted for CD7⁺ and HLA-DR⁺ (OR=3.59, 95%CI: 1.80-7.16, P<0.001; OR=13.41, 95%CI: 4.56-39.45, P<0.001; respectively), and DNMT3A mutation for MPO^-(OR=0.35, 95%CI: 1.48-8.38, P=0.004).

Co-existing FLT3-ITD in NPM1^mut AML independently predicts for CD34⁺ and CD7⁺, co-existing Ras-pathway mutation for HLA-DR⁺ and MPO^-, co-existing TET2/IDH1 mutation for CD34^-, CD7^-, and MPO⁺, and co-existing DNMT3A mutation for HLA-DR⁺, CD7⁺, and MPO^-, thereby providing a new mechanism explanation for the immunophenotypic heterogeneity of these AML patients.