Mutation of the Wilms' tumor 1 gene is a poor prognostic factor associated with chemotherapy resistance in normal karyotype acute myeloid leukemia: the United Kingdom Medical Research Council Adult Leukaemia Working Party.
Virappane P., Gale R., Hills R., Kakkas I., Summers K., Stevens J., Allen C., Green C., Quentmeier H., Drexler H., Burnett A., Linch D., Bonnet D., Lister TA., Fitzgibbon J.
PURPOSE: To determine the clinical relevance of Wilms' tumor 1 (WT1) gene mutations in acute myeloid leukemia (AML) with normal karyotype (NK). PATIENTS AND METHODS: Exons 7 and 9 of WT1 were screened in samples from 470 young adult NK AMLs using a combination of direct sequencing and high-resolution capillary electrophoresis. RESULTS: Overall, 51 mutations were detected in 47 cases (10%): 46 frameshift mutations with insertion/deletion of one to 28 base pairs in exon 7 (n = 45) or exon 9 (n = 1), with a median mutant level of 45% (range, 8% to 86%), and five substitutions in exon 9: D396N (n = 3), H397Y (n = 1) and H397Q (n = 1). Patients with WT1 mutations had an inferior response to induction chemotherapy compared with wild-type cases (complete remission rate, 79% v 90%, odds ratio [OR] = 3.02; 95% CI, 1.17 to 7.82; P = .02), a higher rate of resistant disease (15% v 4%; OR = 9.33; 95% CI, 2.38 to 36.6; P = .001), an increased cumulative incidence of relapse (67% v 43%, hazard ratio [HR] = 3.02; 95% CI, 1.69 to 5.38; P = .0008), with a reduction in both relapse-free survival (22% v 44%; HR = 2.16; 95% CI, 1.32 to 3.55; P = .005) and overall survival (26% v 47%; HR = 1.91; 95% CI, 1.23 to 2.95; P = .007) at 5 years. In multivariate analysis, which included FLT3 internal tandem duplication and NPM1 mutation status, the presence of a WT1 mutation remained an independent adverse prognostic factor. CONCLUSION: WT1 mutations are a negative prognostic indicator in NK AML and may be suitable for the development of targeted therapy.