The Significance of Estimation of Anti- Apoptotic Protein in Acute Leukemia Cases

Abstract

Background Apoptosis is a terminal cell fate that eliminates physiological unneeded or dangerous cells. The Bcl-2 oncoprotein encodes a mitochondrial protein that blocks apoptosis. High levels of Bcl-2 protein are found in different malignancies including acute leukemias and it is thought to be directly involved in the emergence of drug resistance by disrupting &/or delaying apoptotic program and promoting tumor survival. Objectives To analyze the significance of any variation in the level of Bcl-2 expression according to disease progress (from time of diagnosis to time of remission or resistance) in cases with acute leukemia, and whether to consider this variation as a prognostic marker. Methods: Through a prospective study, 25 samples of bone marrow aspirates were taken from different patients who attended the hematology unit of Baghdad teaching hospital in the medical city from December 2005 to July 2006, who proved to have acute leukemia in its different types or subtypes(ALL and AML) & at a variable phases of the disease course. Monoclonal antibody targeted against Bcl-2 oncoprotein via immunocytochemistry staining techniques of these aspirates was performed in order to define the level of Bcl-2 protein carrying cells & looking for any differences in this expression in relation to disease progress or treatment hoping to translate these findings in terms of prognosis. Results Despite the heterogenous expression of Bcl-2 protein carrying cells in each case(0-500 cells out of 500 cells)of AML or ALL , it was found to be in positive correlation with the density of blast cell percentage in the marrow(r=0.515,p=0.008) unlike the relation with total leucocyte count (r=0.364,p=0.074). Conclusion: A good clinical clue to intractable resistant course of the disease at diagnosis is verified in this study when very high level of Bcl-2 protein carrying cells was found. This finding may have a useful clinical application through the recommendation to change therapeutic strategy, at time of diagnosis, to more aggressive protocols, which is agreed by others. There was no chance to study the application of high level of Bcl-2 protein in terms of long-term survival due to short follow up.