Histologic and molecular-genetic characteristics of precancerous lesions in chronic gastritis

Chronic gastritis is an inflammatory condition of the gastric mucosa, which may include glandular alterations. It is most frequently caused by infection with Helicobacter pylori, a smaller proportion is related to chemical agents and autoimmune mechanisms. Chronic gastritis may lead to the development of gastric adenocarcinoma, depending on environmental factors, bacterial strain and host immune response. The vast majority of gastric adenocarcinomas are the final step in a complex cascade process of cancerogenesis involving sequential steps of precancerous lesions – atrophy, intestinal metaplasia and dysplasia.The process of cancerogenesis is associated with progressive genetic and epigenetic alterations, these being more frequent in dysplasia than in atrophic gastritis and intestinal metaplasia. Despite extensive research of gastric cancerogenesis, there are no molecular markers to be used for detecting patients at risk for cancer development.Biopsy remains among the most reliable ways of detecting gastric precancerous lesions. Apart from the correct histologic diagnosis, the assessment of topography is important. Biopsies must be taken according to the updated Sydney protocol. For further classifying patients at risk for gastric cancer, two systems have been developed: OLGA (Operative Link for Gastritis Assessment) and OLGIM (Operative Link for Gastric Intestinal Metaplasia Assessment).Slovenian Society for Gastroenterology and Hepatology, and Slovenian Society for Pathology and Forensic Medicine have accepted guidelines for endoscopic and histologic management of patients with gastric precancerosis. The aim of these recommendations is to diagnose gastric cancer at an early stage and to improve survival of patients with gastric cancer in Slovenia.