Role of Sequential Monitoring of WT1 Gene Expression in Patients With Acute Myeloid Leukemia for the Early Detection of Leukemia Relapse

Abstract

BackgroundWilms' tumor 1 (WT1) mRNA expression is a universal marker of minimal residual disease in patients with acute myeloid leukemia (AML). The aim of this retrospective study was to evaluate the ability of serial measurement of peripheral blood WT1 mRNA levels to predict relapse in patients with AML in remission. Patients and MethodsFrom April 2012 to May 2015, 131 patients with AML were admitted to our hospital. Among them, 55 were examined for WT1 mRNA at least 3 times during complete remission to assess minimal residual disease, and thus were included in the following analyses. ResultsWith a median follow-up duration of 921 days, 34 remained in remission, but their WT1 values frequently increased to 100 copies/μg RNA. Therefore, we focused on the 40 posttreatment observation periods of 37 patients who experienced high WT1 values (defined as those above 100 copies/μg RNA) at least once after they achieved remission. The cumulative incidence of hematologic relapse was 75.8% at 6 months in 26 patients with 2 consecutive high WT1 values, whereas just 1 of the 14 patients with only 1 high WT1 value relapsed (P < .01). Similar results were obtained in subgroup analyses of allogeneic stem cell transplant recipients. ConclusionSequential monitoring of the WT1 mRNA is of value for the early detection of hematologic relapse in patients with AML in remission after chemotherapy or stem cell transplantation.