Flow cytometric significance of cellular alkaline phosphatase activity in acute myeloid leukemia

// Laura G. Rico 1 , Jordi Junca 1 , 2 , Michael D. Ward 3 , Jolene A. Bradford 3 and Jordi Petriz 1 1 Functional Cytomics Group, Institut de Recerca contra la Leucemia Josep Carreras, IJC Campus ICO-Germans Trias i Pujol, Institut Germans Trias i Pujol (IGTP), Universitat Autonoma de Barcelona, UAB, Badalona, Spain 2 Institut Catala d’Oncologia, Hospital Germans Trias i Pujol (HGTiP), Badalona, Spain 3 Thermo Fisher Scientific, Eugene, Oregon, USA Correspondence to: Jordi Petriz, email: jpetriz@carrerasresearch.org Keywords: alkaline phosphatase; acute myeloid leukemia; stem cells; leukemic stem cells; CD34 Received: August 20, 2019     Accepted: November 13, 2019     Published: December 10, 2019 ABSTRACT In this prospective hospital-based cohort study that included 43 newly diagnosed patients with acute myeloid leukemia, flow cytometric cellular alkaline phosphatase (ALP) activity within primitive leukemic cells allowed us to identify two groups of patients at diagnosis according to the numbers of leukemic blasts expressing ≥ 12% of ALP+ cells (27 patients, Group A) and less than 12% of ALP+ cells (16 patients, Group B). Differences in outcome for complete response, relapse or treatment resistance, and exitus were statistically analyzed and were significant, when comparing the two groups. The overall survival (OS) and event-free survival (EFS) differences between Group A and B were statistically significant. The survival of Group A patients was significantly shorter than those for Group B. No significant relationship was detected in outcome when comparing ELN prognostic-risk group based on cytogenetic and molecular profile (patients in the favorable, intermediate, and adverse risk groups). Flow cytometric cellular ALP activity at diagnosis may be used to estimate relapses and disease persistence more accurately. The limitations of our study include the small number of patients enrolled and a short follow-up, due to its prospective nature.