الفهرس 
Reactive Oxygen SpeciesOnly 14 pages are availabe for public view
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Abstract
Introduction: Acute lymphoblastic leukemia (ALL) is the most common cancer in the pediatric population. Oxidative stress may play a role in the development of carcinogenesis. It is well established that some chemotherapeutic agents and radiation therapy generate ROS in patients during cancer therapy. Acquisition of mechanisms to evade apoptosis is a hallmark of cancer. Apoptosis and cancer are opposed phenomena, but ROS may play a key role in both. Aim of the work: is to evaluate oxidative stress (Malondialdehyde and Total Antioxidant Capacity) and apoptosis level in childhood ALL at diagnosis and their impact on outcome at the end of induction of remission phase. Patients and methods: This study included 50 newly diagnosed children with ALL. They were 29 males and 21 females with age mean±SD (6.84±3.73 year). Evaluation of both oxidative stress (Malondialdehyde and Total Antioxidant Capacity) and apoptosis by Fluorometric TUNEL System for patients was done at diagnosis and after the end of induction phase. Results: Our study showed that there was increased oxidative stress in children with ALL at diagnosis (increased MDA and decreased TAC). Also, there was further increase in oxidative stress after 5 weeks treatment with chemotherapy compared to the level at diagnosis. Apoptosis index was found to be higher after 5 weeks treatment with chemotherapy when compared to its level at diagnosis. Oxidative stress was found higher at diagnosis in patient who died before completion of induction. A lower apoptotic index at diagnosis was found among patients who were resistant to treatment. There was a positive correlation between level of oxidative stress and apoptosis index at end of treatment. Conclusion: There is increased oxidative stress in children with ALL (increased ROS or decreased antioxidant capacity) may participate in leukemia pathogenesis. Chemotherapeutic agents may further increase oxidative stress and apoptosis in ALL. Apoptotic index may serve as a predictor for response to chemotherapy. Level of apoptosis after therapy may be correlated with level of oxidative stress although higher oxidative stress may be associated with more side effects and bad prognosis. MDA level at diagnosis may be of prognostic value as regard outcome (death) after induction phase of chemotherapy with cut off value 14.7nmol/ml above which antioxidants therapy may be beneficial to decrease ROS induced harmful effect.