Clinical Utility of Wilms' Tumor 1 Monitoring in Patients with Myeloid Malignancy and Prior Allogeneic Hematopoietic Stem Cell Transplantation.

Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) is 1 of the standard treatments for myeloid malignancy, relapse remains a major obstacle to cure. Early detection of relapse by monitoring of minimal residual disease (MRD) may enable us to intervene pre-emptively and potentially prevent overt relapse. Wilms' tumor 1 (WT1) is well known as a pan-leukemic marker. We retrospectively examined serially monitored WT1 levels of peripheral blood in 98 patients (84 with acute myeloid leukemia and 14 with myelodysplastic syndrome). At the time of allo-HSCT, 49 patients (50%) were in complete remission. Patients were divided into 3 groups according to WT1 levels (<50 copies/µg RNA, 50 to 500 copies/µg RNA and >500 copies/µg RNA). The cumulative incidence of relapse (CIR) and overall survival (OS) differed statistically according to the WT1 levels before allo-HSCT and at days 30 and 60 after allo-HSCT. In multivariate analysis, WT1 >500 copies/µg RNA before and at day 60 after allo-HSCT and WT1 ≥50 copies/µg RNA at day 30 were correlated with CIR. Moreover, WT1 >500 copies/µg RNA at day 60 after allo-HSCT was only correlated with worse OS. Our data suggest that serial monitoring of WT1 levels in peripheral blood may be useful for MRD monitoring and as a predictor of hematological relapse in allo-HSCT.