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

Abstract

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.

Keywords: Acute myeloid Leukemia; CD4; FLT3-ITD; NPM1; immunophenotyping; normal karyotype; prognosis.