It is well known that in healthy conditions at the cellular level, a subtle
balance exists between the free radical generation and the antioxidant defense.
Factors tilting the balance towards free radical generation could lead to oxidative
damage and diseases like degenerative diseases, premature aging, cataract,
carcinogenesis and atherosclerosis [1]. Changes in the enzymatic and nonenzymatic
antioxidative systems and thiobarbituric acid (TBA) reactive products
have been described in different cancers and leukemias [2–6]. Intracellular
superoxide dismutase (SOD) has been shown to have a protective effect and
might be an important factor in determining the resistance of leukemic and
cancer cells against anticancer drugs and radiation [7]; while an absence of
MnSOD activity was described to be a phenotypic feature of tumor cells and of
practical value in cancer therapy [8]. Information on the activities of these
enzymes is conflicting and reports on antioxidant enzymes and lipid peroxidation
are mainly limited to cell lines. The studies in leukemia patients are scanty
[9–16]. Hence the present investigation has been undertaken to study the levels
of free radicals, lipid peroxidation products and antioxidant enzymes SOD and
glutathione peroxidase (GSH-PX) activities in different types of leukemias prior
to therapy.