Immunophenotypic Profile of Acute Myeloid Leukemia in Elderly Patients: a Tertiary Center Experience in Brazil.

Abstract 4137

Acute myeloid leukemia (AML) has an extremely poor prognosis in elderly patients. However, AML is considered a heterogeneous disease, and few reports have analyzed the immunophenotypic profile of AML in elderly patients. We thus analyzed the immunophenotypic markers of newly diagnosed AML in elderly patients in order to determine the incidence of anomalous markers and the correlation with cytogenetic findings. We analyzed samples from 127 patients older than 65 years old with newly diagnosed adult AML seen at our institution from January, 2002 until December, 2007. Markers were assessed by flow cytometry, and the cut-off for positivity was 20%. The expression of CD33 and CD13 was positive in 82.7% and 88.2% of the samples, respectively. HLA-DR was found in 73.2% of cases. The most common aberrant lymphoid markers were CD56 (22.2%), CD7 (16.5%) and CD2 (6.3%). The expression of CD4 and CD11b was correlated with an abnormal karyotype (p<0.05). CD36 was significantly more expressed in patients younger than 75 years of age (p=0.005). AML in elderly patients is a biologically heterogeneous disease, and the immunophenotypic profile reflects this. Future studies should analyze the prognostic value of immunophenotypic abnormalities in this population.