Predictive value of high EVI1 expression in AML patients undergoing myeloablative allogeneic hematopoietic stem cell transplantation in first CR.

The EVI1 gene is a transcriptional regulator of hematopoietic stem cell self renewal and its overexpression is associated with adverse prognosis in de novo AML. Whether the overexpression of EVI1 also predicts poor outcome of AML patients undergoing myeloablative allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first CR (CR1) is still unclear. Thirty-two (21.2%) out of 151 patients were categorized as high EVI1 expression (EVI1+), and 119 (78.8%) patients were categorized as low EVI1 expression (EVI1-). The frequency of EVI1+ was much higher in the adverse-risk group than the intermediate-risk group (53% vs 19%, P=0.005). EVI1+ patients were significantly likely to harbor with translocations involving the MLL gene on 11q23 (8/9). Significantly poor results were observed in the EVI1+ cohort in terms of leukemia-free survival (LFS) (in 24 months 52.6 vs 71.0%, P=0.027), overall survival (OS) (in 24 months 52.8 vs 72.4%, P=0.012), and cumulative incidence of relapse (in 24 months 39.5 vs 22.5%, P=0.013). Multivariable analysis revealed that low EVI1 expression as an independent prognostic factor favoring LFS (hazards ratio=0.47, 95% confidence interval 0.26-0.86, P=0.01) but not OS. Our results indicate high EVI1 expression might predict high risk of relapse in AML patients undergoing myeloablative allo-HSCT in CR1.