Background: Epstein-Barr virus-associated gastric cancer(EBVaGC)has a unique tumor immune microenvironment. We performed a comprehensive analysis of the tumor-infiltrating immune cells in a cohort of EBVaGC in a Chinese population.
Methods: Epstein-Barr encoding region (EBER) in situ hybridization was performed in 1,328 consecutive cases of surgically resected GC. Densities of immune cells, including T cells, B cells, natural killer cells, and macrophages from the patients were calculated after immunohistochemical staining with CD3, CD20, CD57, and CD68 antibodies in tissue microarrays, respectively.
Results: EBVaGC patients accounted for 4.1% (55 of 1,328) cases in the overall population. The average age of patients with EBVaGC was lower than that of non-EBVaGC patients. Histologically, EBVaGC patients exhibited poorly differentiated adenocarcinoma (P = 0.004) and lower frequency of vascular invasion (P = 0.034). The density of CD3+ T lymphocytes (CD3, 23.84 ± 14.49 vs. 12.76 ± 8.93, P < 0.001) and CD68+ macrophages (CD68, 9.73 ± 5.25 vs. 5.44 ± 4.18, P < 0.001) was significantly higher in EBVaGC patients. CD3+ T cell density predicted better 5-year overall survival of EBVaGC patients (P = 0.022).
Conclusions: EBVaGC patients were younger with low-differentiated adenocarcinoma and less vascular invasion. Increased infiltration of multiple immune cells affected the prognosis of patients, especially EBVaGC patients with more CD3+ T lymphocytes, who survived longer.
Keywords: CD3; CD68; Epstein–Barr virus (EBV); gastric cancer; immune microenvironment.
Copyright © 2021 Jia, Guo, Li, Zhang, Feng, Dong, Li, Hu, Li, Xing, Jia and Ji.