Gastric Cancer: recent developments in its etiology and pathogenesis

Abstract

SUMMARY
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.
Key words: Gastric cancer, Carcinogenesis, Oncogenes, Helicobacter
pylori, etiology