Prognostic value of tumor-infiltrating lymphocytes in gliomas: A Systematic Review

Abstract

Background: Glioma is the most common primary brain tumor with poor prognosis. Some studies have learned the prognostic role of tumor infiltrating lymphocytes (TILs) in gliomas. But conflict conclusions were drawn by these studies. In order to reach an agreement, we systematically performed a meta-analysis.Method: A systematic literature research was conducted on the Web of Science, EMBASE, PubMed, Cochrane Library and China National Knowledge Infrastructure. The eligible articles which met the inclusion criteria were included in our study. The clinical outcomes of included patients were defined as progression-free survival (PFS) and overall survival (OS). The basic characteristics and relevant data were extracted. Hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled to evaluate the prognostic role of TILs in gliomas. Newcastle Ottawa Scale (NOS) was used to assess the quality of included studies.Results: Eight articles published from 2008 to 2019 were finally included in our study. And 25 studies were conducted in these articles. We assessed the prognostic role of TILs in gliomas by subgroup analysis according to the subtypes of TILs. The pooled HRs for OS revealed that high density of CD3+ and CD4+ TILs were related to the poor prognosis of gliomas (HR for CD3+ TILs=1.266; HR for CD4+ TILs= 2.128). The pooled HR for PFS indicated that only high density of FOXP3+ TILs were related to poor prognosis (HR=2.785; 95%CI=1.848, 4.197).Conclusion: High density of CD3+ and CD4+ TILs may be a potential candidate for predicting poor OS of gliomas while high density of FOXP3+ TILs may serve as a good biomarker for predicting poor PFS of gliomas.