The prognostic significance of Wilms' tumor gene 1 (WT1) expression at diagnosis in adults with Ph-negative B cell precursor acute lymphoblastic leukemia.

The prognostic significance of Wilms' tumor gene 1 (WT1) expression at diagnosis in adults with B cell precursor acute lymphoblastic leukemia (BCP-ALL) remains poorly understood. A total of 257 adults with Ph-negative BCP-ALL who were consecutively diagnosed and received at least 1 course of induction therapy at our institute were retrospectively analyzed. The WT1 expression patterns were significantly different among the molecularly and cytogenetically defined groups (E2A-PBX1, TEL-AML1, and MLL rearrangements; high hyperdiploidy and B-other). By considering the WT1 expression pattern and the relapse status, 2 cutoff values, 1.8% and 7.2%, were arbitrarily selected to place patients into WT1-low, WT1-inter, and WT1-high groups. In the B-other patients who achieved complete remission (CR), WT1-low and WT1-high patients had similar 3-year relapse-free survival (RFS), disease-free survival (DFS), and overall survival (OS) rates, which were all significantly lower than those of WT1-inter patients. The combined WT1-low/high expression group (n = 132) had significantly lower 3-year RFS, DFS, and OS rates compared with the WT1-inter group (n = 63) of B-other patients (RFS and DFS all P < 0.0001; OS P = 0.0018 and 0.0008). WT1 low/high expression as well as treating with chemotherapy only was independent poor prognostic factors for RFS, DFS, and OS in the B-other patients who achieved CR. Therefore, the molecularly and cytogenetically defined adult Ph-negative BCP-ALL groups have characteristic WT1 expression patterns, and WT1 low/high expression at diagnosis predicts poor outcome in B-other patients.