[Study of gastric adenocarcinomas association with the Epstein-Barr virus-encoded small RNAs].

Objective: Assessment of the incidence of EBV-associated gastric adenocarcinomas in a sample of Russian patients, as well as clarification of the clinical and morphological characteristics and median survival of patients with EBV-associated gastric cancer.

Material And Methods: We used samples of surgical material from 282 patients with a verified diagnosis of gastric cancer. Each sample was stained by in situ hybridization using primers for the Epstein-Barr virus-encoded small RNAs (EBER). The results obtained were compared with the main clinical and morphological characteristics of gastric cancer.

Results: The detection rate of EBV-associated gastric adenocarcinoma in our sample was 9.57%. EBER-positive tumors much more often (=0.021) belong to the intermediate type according to the P. Lauren classification (66.67%) in comparison with EBER-negative tumors (38.82%). EBER-positive tumors significantly more often (=0.035) belong to high-grade tumors - 75.00% in comparison with EBER-negative tumors (52.13%). The overall median survival of all patients with EBER-positive tumors (53.5 months) was higher compared to the overall median survival of all patients with EBER-negative tumors - 36.5 months (=0.5379). The median survival of patients with EBER-positive stage III tumors (30.0 months) was also higher compared to that for patients with EBER-negative tumors - 20.0 months (=0.5622). It was found that a single EBER status is not a significant prognostic factor (HR=1.0143; CI: 0.9897-1.0196).

Conclusion: Separately taken EBER-status is not a significant independent prognostic factor and can be considered only in conjunction with the «classical» clinical and morphological characteristics, primarily with the stage of the tumor process, since it is they that determine the prognostic properties of the tumor.