Tryptase as a Novel Biochemical Marker of Acute Myeloid Leukemia

Abstract

Acute myeloid leukemia, the most common form of acute leukemia in adults, is a clinically and molecularly heterogeneous disease that is curable in about 30% of cases. It is defined as uncontrolled proliferation of cells of the myeloid lineage. The disease results from the accumulation of mutations on oncogenes and/or tumor suppressor genes, and the loss of equilibrium between proliferation and differentiation of the hematopoietic myeloid progenitor cells. Acute myeloid leukemia in adults has a 20% five- year disease-free survival, despite treatment with aggressive cytotoxic chemotherapy. Published data suggest that serum tryptase levels are elevated in a group of patients with AML. In these patients, the enzyme is produced in AML blasts and reflects the burden of leukemic cells. In addition they showed that tryptase is useful for quantitation and monitoring of minimal residual AML. The aim of the present study was todetect mast cell tryptase expression in AML patients using qualitative PT-PCR at time of diagnosis and to evaluate its role as a prognostic factor in those patients. Comparative studies between tryptase expression and clinical, laboratory data and treatment outcome were performed. This study included 40 newly diagnosed AML patients recruited from the Hematology-Oncology unit, Ain Shams University Hospitals. They were18 male and 22 female, their age ranged from 17 to 76 years. Ten healthy subjects were included as a control group. All patients were subjected to the following: 1. Full history taking. 2. Thorough clinical examination lying stress on presence of organomegaly, lymphadenopathy & bleeding tendency. 3. Complete blood count using cell dyne 1500. 4. Bone marrow aspiration & examination of leishman & myeloperoxidase stained films. 5. Immunophenotyping of blast cells using (EPICS-XL Coulter, Hialeh, Florida, USA) Flow Cytometer. 6. Detection of expression of mRNA of mast cell tryptase using qualitative RT-PCR. All patients were followed up for a period of 6 months. We found that mast cell tryptase gene expression was positive in 17/40 (42.5%) patients