ИСТИНА

Background & objectives. Gastric adenocarcinoma associated with the Epstein-Barr virus is a separate molecular subtype of gastric cancer with a characteristic set of genetic disorders and clinical and morphological features. In this study we performed EBER identification in patients from the Russian Federation. Methods. We used samples of surgical material from 233 patients from Russian Federation with a verified gastric cancer. EBER chromogenic hybridization in situ (EBER-CISH) was performed in each case. The results of EBER identification were compared with the main clinical and morphological characteristics of gastric cancer. Results. A total of 18 EBER-positive gastric adenocarcinomas and 215 negative cases were identified using EBER-CISH. The frequency of occurrence (incidence) was 7.73%. As in other described patient populations the identified EBV-associated gastric adenocarcinomas were characterized by a less aggressive phenotype. EBER identification in gastric adenocarcinomas was statistically significantly associated with the absence of distant metastases (p=0.047). Among all 18 identified cases of EBV-associated adenocarcinomas there were no cases with distant metastases and, accordingly, IV stage tumors. There were no statistically significant differences for other TNM clinical stages. This fact can be explained by the significant dominance of 106 cases of III stage tumors in our sample. Conclusion. It is known that the prevalence of EBV-associated gastric adenocarcinoma differs depending on the population.The results obtained showed that the incidence of EBV-associated gastric adenocarcinoma in the studied sample of cases from Russian Federation is 1.27% lower than the world average of 9%. This work was supported by Russian Science Foundation (RSF) grant number 20-75-00037.