Gastric Cancer: recent developments in its etiology and pathogenesis

During recent years significant progress has been made concerning our understanding the role of various factors involved in the etiology and pathogenesis of gastric carcinoma. Several factors are suspected to play a role in gastric carcinogenesis including environmental factors (diet, exogenous chemicals), intragastric synthesis of carcinogens, infectious factors (Helicobacter pylori) and genetic ones. Gastric tumorinogenesis is a multifactorial and multistep process, involving accumulation of genetic and epigenetic alterations in oncogenes, tumor-suppressor genes, cell-adhesion molecules, telomere and telomerase activity, as well as genetic instability at several microsatellite loci. These sequential alterations differ between the two histological types of gastric cancer (diffuse and intestinal). Genetic instability, chromosomal instability and immortality participate in the initial step of gastric carcinogenesis. According to the World Health Organization, Helicobacter pylori could be classified as a carcinogen of type I. It causes chronic gastritis leading to atrophy, intestinal metaplasia, dysplasia and adenocarcinoma. The knowledge of these events, some of which appear in the early stage of gastric carcinogenesis, could be of value in relation to the prevention strategies and early diagnosis of this lethal condition.