Prognostic role of tumor-infiltrating lymphocytes in gastric cancer: A systematic review and meta-analysis

Abstract

Background

To analyze the relationship between tumor-infiltrating lymphocytes (TILs) subtypes and infiltration locations and the prognosis of gastric cancer (GC) patients.

Methods

Eligible articles were obtained through systematic retrieval and rigorous screening, collecting study information and extracting hazard ratio (HR), 95 % confidence interval (CI) for pooled analyses of disease-free survival (DFS) and overall survival (OS).

Results

Higher CD4⁺ TILs were correlated with favorable OS (HR=0.79, 95 %CI: 0.66–0.94, P = 0.009), the similar results were observed in tumor center and in infiltration margin. Higher CD8⁺ TILs prolonged DFS (HR=0.69, 95 %CI: 0.51–0.95, P = 0.02) and OS (HR=0.96, 95 %CI: 0.94–0.99, P = 0.006); For OS, tumor center and infiltration margin groups showed positive results. Neither the overall analysis nor the subgroup analyses indicated that the level of FOXP3⁺ TILs was associated with prognosis (DFS: HR=0.89, 95 %CI: 0.66–1.19, P = 0.42; OS: HR=0.98, 95 %CI: 0.85–1.13, P = 0.75). Pooled results revealed that higher CD3⁺ TILs were correlated with favorable DFS (HR=0.69, 95 %CI: 0.56–0.84, P = 0.0003) but not OS (HR=1.00, 95 %CI: 0.99–1.01, P = 0.48).

Conclusions

High infiltrating CD3⁺, CD4⁺, CD8⁺ T cells prolong survival, and FOXP3⁺ subset is not related to prognosis in GC. For CD4⁺ and CD8⁺, positive correlations between the infiltration level and OS were present in tumor center and infiltration margin groups.