MnSOD Val-9Ala Gene Polymorphism and Susceptibility to Gastric Cancer in Iran

Gastric cancer (GC) is one of the most important diseases that affected health in all over the world (Zare et al., 2013; Lin et al., 2014). Gastric cancer is the most general deadly cancer with approximately 738,000 deaths per year that over 70% of them occur in the developing countries (Jemal et al., 2011). Northern and northwestern regions of Iran are high risk areas for gastric cancer (Fallah, 2007; Moradi et al., 2013). Different frequency of gastric cancer in worldwide can be due to variation in the genetic background, dietary habits, living situation and also the prevalence of Helicobacter pylori (H. pylori) infection which has been classified as Group I carcinogens (Humans, 1994). H. pylori infections can induce the host inflammatory responses and oxidative stresses. Interleukin-8 is induced by the gastric epithelium cells that infected by H. pylori, contributes to the production of too much amounts of toxic reactive oxygen species (ROS) and can causes induction of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α) and some other interleukins (Augusto et al., 2007a). Oxidative stress that caused by ROS is involved in human carcinogenesis (Cerutti., 1985). ROS, as candidate agents in the growth of cancer, generated in normal respiration of cells and during xenobiotics metabolism, causes damage to cell membranes, mitochondria and DNA molecule. (Egan et