Prognostic value of immunophenotyping and gene mutations in elderly patients with acute myeloid leukemia with normal karyotype

Abstract

Elderly patients with acute myeloid leukemia generally have a poor prognosis and a highly heterogeneous clinical outcome. Prognostic indicators are required for and aid in patient stratification. However, the prognostic value of genetic mutations and immunophenotypic features in elderly normal karyotype acute myeloid leukemia, the largest cytogenetic risk group, remains unclear. We investigated the genetic mutations NPM1, FLT3-ITD, and FLT3-TKD and expression of the membrane antigens CD7, CD15, CD34, and CD56 in 144 elderly patients with de novo normal karyotype acute myeloid leukemia to retrospectively analyze the prognostic and clinical relevance of these parameters. CD7, CD15, CD34, and CD56 were expressed in 24%, 47%, 52%, and 15% of patients, respectively. NPM1 and FLT3-ITD mutations were detected in 51% and 17% of patients, respectively. Complete remission was obtained in 94 patients (65%), and the median overall survival was 16.5 months. Univariate analysis detected 5 markers with prognostic relevance: high leukocyte count, FLT3-ITD mutations, NPM1 mutations, CD34 expression, and CD56 expression in acute myeloid leukemia blasts. In multivariate analysis, patients with NPM1 predicted a higher complete remission (CR) rate (P = .016), longer event-free survival (P = .008), and longer overall survival (P = .049). FLT3-ITD mutations predicted a shorter event-free survival (P = .002) and shorter overall survival (P < .001). CD56 remained an independent predictor for lower CR rate (P = .021) and shorter event-free survival (P = .002). Our data highlight the prognostic importance of both genetic and immunophenotypic characteristics in this population of elderly patients with newly diagnosed normal karyotype acute myeloid leukemia. By combining genetic and immunophenotypic markers, we can divide patients into distinct prognostic groups with important implications for prognostic stratification and risk-adapted therapy.