NPM1 High Mutant Allele Burden is an Adverse Prognostic Factor for AML Patients with Mutated NPM1 / 中国实验血液学杂志

ABSTRACT

OBJECTIVE@#To investigate the clinical features, accompanying gene mutation characteristics and prognostic factors of adult patients with acute myeloid leukemia with mutated NPM1 (NPM1AML).@*METHODS@#Seventy-three patients with newly diagnosed adult NPM1AML were selected. The mutations of 22 genes were detected by second generation sequencing and 43 fusion genes of AML were detected by real-time fluorescent quantitative PCR. The Kaplan-Meier survival curve and Cox multivariate regression analysis were used to study the prognostic factors.@*RESULTS@#A total of 74 NPM1 site mutations were detected in 73 patients with NPM1AML. The incidence rates were 92.0% L287fs, 2.7% Q289fs and W288fs, 1.4% L258fs and Q289H, among which 1 patient had 2 NPM1 mutations; the different mutation sites had no effect on the prognosis of NPM1AML. The median value of NPM1 variant allele frequency (VAF) was 35.4% (1.8%-56.6%). Based on the uppermost quartile of 38.4%, the patients were classified as NPM1 VAF>38.4% (NPM1AML) and NPM1 VAF≤38.4% (NPM1AML). Compared with NPM1AML, the early mortality rate was statistically significantly higher (33.3% vs 7.3%, P38.4% was an independent prognostic factor for EFS (HR=3.1, 95% CI 1.6-6.4, P<0.01) and OS (HR=3.0, 95% CI 1.4-6.2, P<0.01).@*CONCLUSION@#The NPM1 gene mutation in AML patients often is accompanied by other gene mutations, while the coexistence of fusion genes is rare; high NPM1 mutant allele burden is an independent prognostic factor for adult AML patients with mutated NPM1.