Frequency and Clinical Impact of WT1 Mutations in the Context of CEBPA-Mutated Acute Myeloid Leukemia

Abstract

Introduction: Several studies have confirmed that mutations in the Wilms tumor 1 (WT1) gene occur in adult acute myeloid leukemia (AML). However, few data are available regarding the incidence of WT1 mutations in CEBPAmut AML and their impact. Methods: We retrospectively analyzed the frequency and clinical impact of WT1 mutations in 220 newly diagnosed AML patients with CEBPA mutations. Chromosome karyotype analysis was performed by R or G banding method and further confirmed either by fluorescence in situ hybridization (FISH) and/or by multiple reverse transcription polymerase chain reaction (multiple RT-PCR). Mutations were detected with a panel of 112 mutational genes using next-generation sequencing (NGS). FLT3-ITD, NPM1 and CEBPA mutation were detected by PCR Sanger sequencing.Results: Overall, 30 WT1 mutations were detected in 29 of the 220 patients (13.18%) screened. These mutations clustered overwhelmingly in exon 7 (16 mutations in 15 patients), but they were also detected in exon 8 (n=6) and exon 9 (n=8). WT1-mutated (WT1mut) patients presented with lower platelet counts (P=0.0481), higher WT1 expression (P=0.0371), and a negative trend with the M5 subtype (P=0.07) compared to WT wild-type (WTwt) patients. WT1 mutations were found to be significantly more frequent in AML patients with double-mutated CEBPA (CEBPAdm) than in AML patients with single-mutated CEBPA (P=0.043). Of note, the concomitant mutations in epigenetic regulators were inversely correlated with WT1 mutations (P=0.003). Patients with newly diagnosed WT1mut AML had inferior relapse-free survival, event-free survival and overall survival compared with patients with WT1wt AML (P=0.002, 0.004, and 0.010, respectively). Conclusion: Our data showed that WT1 mutations are frequently identified in CEBPAmut AML, especially in CEBPAdm AML. Patients with WT1 mutations show distinct clinical features, a spectrum of comutations, and poor prognosis compared to WT1 wild-type patients.