Objective   This study was conducted to investigate Epstein-Barr virus (EBV) infection in gastric cancer in Wuwei area of Gansu province (China) and the roles of miR-101, EZH2, and COX-2 in EBV-associated gastric carcinomas (EBVaGC).

  Methods   Tissue microarray technique, immunohistochemistry, and in situ hybridization were performed to detect the expression of EBV-encoded small RNAs (EBERs), miR-101, EZH2, and COX-2, in gastric cancer tissues (n=120) and the corresponding adjacent tissues (n= 120).

  Results   The positive rate of EBV was 10.0% in 120 cases of gastric cancer tissues. EBVaGC was not significantly associated with lymph node metastasis and developed most often in the cardia and body (P<0.05). The differences in the positive rates of miR-101, EZH2, and COX-2 in 120 cases of gastric cancer tissues and corresponding adjacent tissues were significant (P<0.05). The differences in the positive rates of miR-101, EZH2, and COX-2 in 12 cases of EBVaGC and in 108 cases of EBV-negative gastric cancer (EBVnGC) tissues were significant (P<0.05). The infection of EBV in gastric cancer tissues was positively related to miR-101 expression. By contrast, miR-101 expression was negatively related to lymph node metastasis and expression of COX-2 and EZH2 in EB-VaGC tissues (P<0.05).

  Conclusion   EBV infection was related to gastric cancer in Wuwei area of Gansu province. EBVaGC and EB-VnGC have significant differences in lymph node metastasis and in the location of cancer. MiR-101, EZH2, and COX-2 were related to the development of EBVaGC.