KRAS and gastric cancer: Constitutive activation of Ras and Ras-related proteins promotes cell proliferation and increase invasion and metastasis while inhibiting apoptotic cell death. K-RAS gene was found to be mutated (codon-12) in intestinal-type cancer, but not in diffuse-type cancer [21]. K-RAS gene mutations in H. pylori-associated chronic gastritis are more frequent in gastric cancer patients than in cancer-free patients, suggesting that K-RAS mutation may be involved in the early stage of gastric carcinogenesis [22].