The relevance of preferentially expressed antigen of melanoma (PRAME) as a marker of disease activity and prognosis in acute promyelocytic leukemia

Abstract

Background The gene for preferentially expressed antigen of melanoma (PRAME) has been shown to be over-expressed in acute promyelocytic leukemia, but its actual incidence and clinical impact are still unknown.Design and Methods We studied PRAME expression at diagnosis using real-time quantitative polymerase chain reaction in 125 patients with acute promyelocytic leukemia enrolled in the Spanish PETHEMA-96 (n=45) and PETHEMA-99 (n=80) clinical trials. In addition, PRAME expression was evaluated as a marker of disease activity in 225 follow-up samples from 67 patients with acute promyelocytic leukemia.Results At diagnosis, PRAME expression in patients with acute promyelocytic leukemia was significantly higher (p100-fold PRAME expression (86% vs. 74%; p=0.03), and this cut-off established two sub-groups with different relapse-free survival rates among patients with a white cell count 109/L, although differences were not statistically significant. In multivariate analysis, white cell count >109/L (p90% (p=0.001), and PRAME expression 10-fold increase in PRAME expression levels.Conclusions Low PRAME expression defines a subgroup of patients with acute promyelocytic leukemia with a short relapse-free survival. This marker could be useful as a secondary marker for monitoring patients with acute promyelocytic leukemia.