Number of RUNX1 mutations, wild-type allele loss and additional mutations impact on prognosis in adult RUNX1-mutated AML.

RUNX1-mutated acute myeloid leukemia (AML) show a distinct pattern of genetic abnormalities and an adverse prognosis. We analyzed the impact of multiple RUNX1 mutations and RUNX1 wild-type (WT) loss in 467 AML with RUNX1 mutations (mut): (1) RUNX1 WT loss (n=53), (2) >1 RUNX1mut (n=94) and (3) 1 RUNX1mut (n=323). In 1 RUNX1mut, +8 was most frequent, whereas in WT loss +13 was the most abundant trisomy (+8: 66% vs 31%, P=0.022; +13: 15% vs 62%, P<0.001). Analyses of 28 genes in 163 selected cases revealed SRSF2 (39%), ASXL1 (36%), DNMT3A (19%), IDH2 (17%) and SF3B1 (17%) as most frequently mutated genes. RUNX1 WT loss showed a higher frequency of ASXL1mut compared with the other cases (50% vs 29%, P=0.009). Median overall survival (OS) in the total cohort was 14 months. WT loss (OS: 5 months) and >1 RUNX1mut (14 months) showed an adverse impact on prognosis compared with 1 RUNX1mut (22 months; P=0.002 and 0.048, respectively). Mutations in ASXL1 and ⩾2 additional mutations correlated with shorter OS (10 vs 18 months, P=0.028; 12 vs 20 months, P=0.017). Thus, the number of RUNX1mut, RUNX1 WT loss and the number and type of additional mutations is biologically and clinically relevant.