Genetic Instability in Nuclear and Mitochondrial DNAs during Gastric Carcinogenesis

Gastric cancer (GC) is highly prevalent in Asia and the third most common cause of cancer death after lung cancer and liver cancer in Korea (Jung et al., 2012). The 5-year survival rate for gastric cancer is over 60%, however, the late onset of clinical symptoms occurred late diagnose at an advanced stage, which limits available therapeutic approaches in more than 50% of cases (Strong et al., 2010). A better prognostic result was obtained in Asian, possibly attributable to early detection and approaches. According to c l inicopathological s tudies , adenocarcinoma is the major histological type of gastric cancer, over 90% of all gastric malignancies, and it is divided into two distinct pathological entities, intestinal and diffuse types by Lauren classification. Intestinal type is associated with certain dietary factors, such as high intake of salt, smoked meats, and food preserved with nitrites or nitrates (Hamilton and Meltzer, 2006; Shah et al., 2011). It develops via an intestinal metaplasiaadenoma-carcinoma sequences by the accumulation of gene alterations. Histologically it is well differentiated and is seen more frequently in elder patients (Hamilton and Meltzer, 2006). In comparison to intestinal-type GC, diffuse type is less related to environmental influences and poorly differentiated with infiltrating, non cohesive cells (Correa et al., 1975; Shah et al., 2011). Helicobacter pylori infection plays a significant role in the development of intestinal GC through chronic inflammation, but without occurrence of gastric atrophy and intestinal metaplasia (Forman et al., 1991; Parsonnet et al., 1991).