Comparison of clinicopathological parameters with the presence of Epstein-Barr virus and the absence of DNA mismatch repair proteins in gastric adenocarcinomas.

Background: High mortality and poor prognosis are seen in gastric adenocarcinomas (GAs). Therefore, investigation of the factors related to GA prognosis is important. Objective: To investigate the association between clinicopathological parameters and DNA mismatch repair (MMR) proteins as well as Epstein-Barr virus (EBV) in GAs. Methods: Expression of MMR proteins and EBV positivity of 77 patients diagnosed with GA were evaluated using immunohistochemistry. Survival data of the patients were also considered. Results: Significant correlations were found between EBV positivity and gender, perineural invasion (PNI), and histological type. PNI was less common in EBV-positive patients, and EBV positivity was highly correlated with lymphoid stromal adenocarcinoma. Tumor budding was significantly correlated with histological type and grade, lymphovascular invasion (LVI), PNI, lymph node metastasis, and post-diagnosis survival time. Moreover, tumor-stroma ratio was correlated with tumor stage. Additionally, tumor location, histological grade, tumor budding, PNI, and pathological stage were associated with survival. Also, EBV positivity was significantly associated with histological type, PNI, tumor location, and gender. However, MMR and EBV positivity were not significantly correlated to tumor microenvironment and prognosis. It was noteworthy that the mortality rate was much higher in patients with PNI compared with those without PNI. Conclusion: Our findings support that the tumor microenvironment is significantly associated with GA prognosis.