Expression of some apoptosis-controlling proteins in children with acute lymphoblastic leukemia

ABSTRACT

The aim of this study was to determine the serum levels of some apoptosis-controlling proteins [Bcl-2 and soluble Fas] in children with acute lymphoblastic leukemia [ALL], and to find out the relation between their expression and the clinico-laboratory parameters as well as outcome of the disease. The study included 20 children with ALL [13 males and 7 females], their age ranged from 0.5-13 years. Twelve apparently healthy children were included as a control group. Cases and controls were subjected to full history taking, thorough clinical examination, and determination of serum levels of Bcl-2 and soluble Fas proteins [sFas], and complete blood picture [CBC]. Bone marrow examination, CSF examination, immunophenotyping, and radiological evaluation were done for cases only. One-year follow-up of cases was performed for evaluation of the prognosis and the outcome of the disease. The results showed that serum levels of Fas and Bcl-2 were significantly elevated in patients with ALL when compared to control [P 0.007 and P 0.003 respectively]. Serum levels of sFas were significantly elevated in cases with CNS involvement compared to those without CNS involvement [p <0.01], in cases with white blood cell count >50.000/mm[3] in peripheral blood compared to those having lower cell counts [p<0.05], and in patients with T cell lineage compared to those with B lineage [p<0.01]. Serum levels of Bcl-2 were not significantly different as regard these parameters. Serum levels of Bcl-2 were significantly lowered after treatment [P<0.001], while serum sFas didn't differ significantly before and after treatment. Levels of sFas and Bcl-2 were higher in ALL patients resistant to induction chemotherapy compared to those showing complete remission, but the difference did not reach the level of significance. Our study shows that 1] increased serum expression of Bcl-2 and soluble Fas [sFas] can be demonstrated in children with ALL. 2] increased expression of sFas [but not Bcl-2] has been found to be associated with certain unfavorable prognostic features such as T-lineage ALL, CNS involvement, and higher WBCs count and 3] the higher levels of sFas and Bcl-2 in these cases were not associated with poor response to therapy