Serum nitric oxide and peroxynitrite in breast cancer patients

Cancer results from deregulation of cellular pathways, leading to rapid multiplication of cells that trigger formation of new blood vessels (angiogenesis), which are required for tumour growth. A marker of angiogenesis thus can help in management of tumour. In this regard, serum nitric oxide was measured in breast cancer patients. Several tumour cell lines found to express enzyme NO synthase. In tissues with increased production of NO, reaction of nitrogen and oxygen (O2) leads to reactive nitrogen species like dinitrogen trioxide (N2O3) and peroxynitrite (ONOO). These reactive nitrogen species will inhibit DNA repair system and also cause oxidative and nitosative stress Objective/Aim: Aim of this study was to measure and compare serum nitric oxide and peroxynitrite in biopsy proven breast cancer patients and healthy controls Materials and Methods: This prospective cross-sectional study included 46 newly diagnosed (preoperative) breast cancer female patients (Mean Age =56±12 years). Controls consisted of 46 healthy females were included in the study with no previous disease, alcohol or any drug consumption. Blood samples were collected from all the subjects into empty red capped vacutainer and were analyzed for serum Nitric oxide and peroxynitrite. Results: Nitric oxide (NO) and Peroxynitrite were significantly increased in breast cancer patients compared with controls. Conclusions: Stimulation of host defence system against tumor growth results in elevated NO levels in cancer patients. Over expression of Nitric oxide may lead to DNA damage by synthesis of carcinogenic nitrosamines, production of RNS and inhibition of DNA damage repair enzyme mechanism.