Sequential alterations in gastric biopsies and tumor tissues support the multistep process of carcinogenesis

Abstract

Gastric cancer is the second leading cause of cancer related death worldwide. In the UAE, recent data show an increase in the number of patients with gastric cancer highlighting the need for greater understanding of its pathogenesis. Gastric cancer is generally believed to develop on a background of chronic atrophic gastritis which eventually leads to intestinal metaplasia, dysplasia and finally invasive carcinoma. Recently this multistep process of carcinogenesis has been challenged. Therefore, the aim of this study is to define alterations in antral mucosal biopsies and cancer tissues to investigate whether they could be used to assemble a tissue array supporting the multistep model of carcinogenesis. Gastric mucosal tissues were obtained from informed individuals undergoing endoscopy (for upper gastrointestinal symptoms) and gastrectomy (for adenocarcinoma) in Tawam Hospital. All tissues were processed for microscopic examination. Eighty nine antral biopsies were categorized as: normal (33%), mild superficial gastritis (34%) and severe atrophic gastritis (33%). About 5% of the latter exhibited evidence of intestinal metaplasia. Cancer tissues obtained from three patients were microscopically examined in three regions: safe resected margin, tumor edge and tumor center. Progressive changes in mucosal thickness, dysplasia and cellular transformation were observed, and when compared with alterations in biopsies, all appeared to represent a continuum of progression toward invasive adenocarcinoma. In conclusion, the tissue array presented in this study supports the multistep process of gastric carcinogenesis and will be helpful in examining the expression pattern of tumor markers or molecules that could help in the early detection of gastric cancer.