en Biochimestry Biochimestry Original Article Original Article <p><span style="font-size:14px;"><span style="font-family:times new roman;"><span style="color:#0000FF;"><strong><em>Background: </em></strong></span>Recent studies have suggested the importance of oxidant/antioxidant status in initiation and progression of breast cancer. The aim of this study was to evaluate oxidative stress markers in breast cancer patients before and after 3 cycles of chemotherapy with adriamycin and cytoxan (AC). Also, in this study the effect of age and the stage of disease on oxidative stress markers were compared and evaluated.<br> <span style="color:#0000FF;"><strong><em>Methods: </em></strong></span>This study included 60 women with newly diagnosed stage II-III breast cancer who underwent chemotherapy with AC as the therapy-first strategy after surgery. Serum samples were obtained before treatment and after the third chemotherapy. Then, serum total antioxidant status (TAS) and malondialdehyde (MDA) as lipid peroxidation marker were analyzed. Moreover, the effects of the subject&rsquo;s age and clinical disease stage were investigated.<br> <span style="color:#0000FF;"><strong><em>Results: </em></strong></span>A concurrent significant increase in MDA (p<0.001) and a significant decrease in TAS (p<0.001) were also observed after 3 cycles of AC chemotherapy. In addition, some changes were found in the status of oxidative stress markers which were associated with age and clinical disease stage.<br> <span style="color:#0000FF;"><strong><em>Conclusion: </em></strong></span>Our data indicated that chemotherapy with AC increase the oxidative stress in breast cancer patients. The present study indicated that higher stages of the breast cancer are associated with significant increases of oxidative stress markers.</span></span></p> Breast cancer, Chemotherapy, Malondialdehyde, Oxidative stress, Total antioxidant status 264 268 http://caspjim.com/browse.php?a_code=A-10-630-1&slc_lang=en&sid=1 Mostafa Taherkhani taherkhani7816@gmail.com 10031947532846009989 10031947532846009989 No Student Research Committee, Babol University of Medical Sciences, Babol, Iran. Soleiman Mahjoub Smahjoub20@gmail.com 10031947532846009990 10031947532846009990 Yes Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Dariush Moslemi moslemi_d@yahoo.com 10031947532846009991 10031947532846009991 No Department of Radiation Oncology, Babol University of Medical Sciences, Babol, Iran Ahmad Karkhah ahmadkarkhah@ymail.com 10031947532846009992 10031947532846009992 No Cellular and Molecular Biology Research Center, Student Research Committee, School of Medicine, Babol University of Medical Sciences, Babol, Iran