MicroRNA 181a (miR-181a) expression as a prognosticator in cytogenetically normal acute myeloid leukemia (CN AML)

Abstract

7001 Background: We showed recently that CEBPA mutations (mut) in CN AML are associated with better outcome and a unique microRNA expression profile, including miR-181a upregulation. Here we tested if miR-181a expression can predict outcome independently. Methods: We analyzed 187 de novo CN AML adult patients (pts) aged <60 years (y; median 45) similarly treated on CALGB 9621 and 19808. Of these, 122 had molecular high risk [FLT3-ITD or NPM1 wild type (wt)] and 65 low risk (no FLT3-ITD, NPM1 mut) CN AML. FLT3, NPM1, CEBPA, MLL, and WT1 mutations, and ERG and BAALC expression were analyzed centrally. miR-181a expression was measured in pretherapy marrow using OSUCCC v3.0 arrays. The mean of 2 miR-181a probe log intensities was used as a continuous variable for analyses. Results: Higher miR-181a levels (miR-181a↑) were associated with CEBPA mut, NPM1 wt, no FLT3-TKD, lower ERG expression, higher %FAB M1/M2, lower WBC and age, higher blood blasts, and lower % gum hypertrophy. miR-181a↑ tended to associate with more complete remissions (CRs; p = .07) and significantly associated with longer disease-free (DFS; p = .05) and overall (OS; p = .01) survival (median follow-up 6.5 y for pts alive). A stronger prognostic impact of miR-181a was observed in the molecular high risk group, where miR-181a↑ predicted more CRs (p = .03), and longer DFS (p = .0002) and OS (p = .0001). In multivariable analyses of the molecular high risk group, miR-181a↑independently predicted CR, and longer DFS and OS (Table). For descriptive purposes, we dichotomized pts at the median miR-181a expression value. For high v low miR-181a expressers, CR rates were 84% vs 72% and 5 y DFS and OS rates 43% vs 18% and 48% vs 19%, respectively. Conclusions: miR-181a expression is a prognostic marker in CN AML, mainly in the molecular high risk group, where it predicts outcome independently of other variables including CEBPA mutations. As miR-181a↑ confer better treatment response, novel approaches increasing miR-181a levels might benefit not only CN but also other AML pts. [Table: see text] No significant financial relationships to disclose.