Expression of CD4 is correlated with an unfavorable prognosis in wild-type NPM1, FLT3-ITD-negative cytogenetically normal adult acute myeloid leukemia.

INTRODUCTION

In the cytogenetically normal population of AML (CN-AML), FLT3-ITD-positive and wild-type NPM1 is correlated with a worse outcome, and FLT3-ITD-negative with NPM1-mut is correlated with a better outcome. This leaves a large subpopulation of CN-AML patients without NPM1 or FLT3-ITD mutations with heterogeneous outcomes with overall survivals (OS) ranging from several weeks to years. Therefore, new prognostic markers are needed to better risk stratify this subset of patients.

METHODS

The retrospective study included 60 de novo adult AML patients diagnosed at our institution with normal karyotype, no FLT3-ITD or NPM1 mutations, and who did not receive allogeneic hematopoietic stem cell transplantations. We investigated the prognostic significance of immunophenotypic markers and clinical laboratory features in this double-negative population.

RESULTS

Older age (>60) and CD4 expression (14%) were significantly correlated with shorter event-free survival (EFS) (P < 0.001, P = 0.016, respectively). Expression of CD56 (12%), as well as lack of CD34 expression (19% of the cases), was also associated with a worse EFS (P = 0.048, P = 0.028, respectively). On multivariable analysis, CD4 expression and old age (>60) were identified as independent predictors for worse EFS (P = 0.016; P = 0.001, respectively) and OS (P = 0.048; P = 0.028, respectively).

CONCLUSIONS

Our results indicate that CD4 expression and older age are adverse prognostic factors in wild-type NPM1, FLT3-ITD-negative CN-AML.