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

Abstract

e15578 Background: Tumor-infiltrating lymphocytes(TILs) may act as major determinants of the host immune response to tumor cells. However, the potential prognostic value of TILs in gastric cancer remains controversial. This meta-analysis analyzed the associations between TILs and survival outcomes in gastric cancer. Methods: Eligible 24 published studies were identified by searching the PubMed and Google scholar databases. The primary clinical outcome was defined as overall survival (OS) or disease-free survival (DFS), which were analyzed by subgroups such as TILs subtype. The total of the study sample sizes in eligible 24 published studies was 3,229, which ranged from 52 to 273 (median, 120) patients. All studies were non-randomized and retrospective study. The only multivariate hazard ratio(HR) among patient survival data were pooled, and pooled multivariate HR with 95% confidence intervals (95% CI) were used to calculate the strength of this association between TILs expression and survival outcome. Results: The pooled multivariate hazard ratios suggested that high expression of TILs was associated with better overall survival outcome (pooled HR = 0.69, 95% CI 0.57–0.82), compared to low TILs expression in twenty-three eligible studies, particularly in CD8(+) lymphocytes (pooled HR = 0.63, 95% CI 0.48 –0.83). In contrast, a pooled analysis of the FOXP3 (+) T cells or Treg subgroup showed that high FOXP3 (+) expression was negatively correlated with OS (pooled HR = 1.88, 95% CI 1.34 –2.63). In an analysis of seven studies on DFS, the infiltration by TILs, CD4(+) or CD8(+) lymphocytes (pooled HR = 0.59, 95% CI 0.42 –0.81), not by the infiltration of FOXP3 (+) T lymphocytes (pooled HR = 1.82, 95% CI 1.30 – 2.53), was significantly associated with better survival outcome. Conclusions: The results from this meta-analysis suggest that TILs and TILs subsets expression can be a potential prognostic biomarker in patients with gastric cancer. Key Words: Tumor-infiltrating lymphocytes, gastric cancer, prognosis, meta-analysis