The Participation of p53 and bcl-2 Proteins in Gastric Carcinomas Associated with Helicobacter pylori and/or Epstein-Barr Virus (EBV)

Abstract

In the presented studies p53 and bcl-2 proteins expression were evaluated in samples of gastric carcinomas in patients with Helicobacter pylori or EBV or without H. pylori/EBV infection. The studies were conducted on 64 adult patients with gastric adenocarcinomas: 16 patients with H. pylori (cagA+)-positivity (group 1), 14 with EBV-positive tumours (group 2), 12 with H. pylori/EBV-positive tumours (group 3) and 22 patients with H. pylori/EBV-negative tumours (group 4). H. pylori presence in gastric tumour specimens was detected using Giemsa staining and bacterial culture technique. Moreover, cagA gene was detected using PCR. EBV infection was detected based on EBER presence in the tissue by RNA in situ hybridization. Expressions of p53 and bcl-2 proteins were analysed using immunohistochemistry. Expression of p53 was noted in 14 (84%) patients from group 1, 8 (57%) patients from group 2, 7 (58%) patients from group 3, and 19 (86%) patients from group 4, whereas expression of bcl-2 was noted in 12 (75%) patients from group 1, in 10 (71%) patients from group 2, 9 (75%) patients from group 3, and 6 (27%) patients from group 4. The obtained results allow the conclusion, that H. pylori (cagA+)-associated development of the gastric adenocarcinoma is determined by abnormalities in the p53 protein function and overexpression of anti-apoptotic bcl-2 protein, whereas EBV-associated adenocarcinomas seem to be related with apoptosis resistance associated with bcl-2 overexpression.