The prognostic value of intratumoral and peritumoral tumor-infiltrating FoxP3+Treg cells in of pancreatic adenocarcinoma: a meta-analysis

BACKGROUND: Tumor-infiltrating lymphocytes (TILs) are major participants in the tumor microenvironment. The prognostic value of TILs in patients with pancreatic cancer is still controversial. METHODS: The aim of our meta-analysis was to determine the impact of FoxP3+Treg cells on the survival of pancreatic cancer patients. We searched for related studies in PubMed, EMBASE, Ovid, and Cochrane Library from the time the databases were established to Mar 30, 2017. We identified studies reporting the prognostic value of FoxP3+Treg cells in patients with pancreatic cancer. Overall survival (OS) and disease-free survival (DFS)/progression-free survival (PFS)/relapse-free survival (RFS) were investigated by pooling the data. The pooled hazard ratios (HRs) with 95% confidence intervals (95% CI) were used to evaluate the association between FoxP3+Treg cells and survival outcomes of pancreatic cancer patients. A total of 972 pancreatic cancer patients from 8 studies were included in our meta-analysis. RESULTS: High levels of infiltration with FoxP3+Treg cells were significantly associated with poor OS (HR=2.13; 95% CI 1.64–2.77; P<0.05) and poor DFS/PFS/RFS (HR=1.70; 95% CI 1.04 ~ 2.78; P< 0.05). Similar results were also observed in the peritumoral tissue; high levels of FoxP3+Treg cells were associated with poor OS (HR =2.1795% CI, CI 1.50–3.13). CONCLUSION: This meta-analysis indicated that high levels of intratumoral or peritumoral FoxP3+Treg cell infiltration could be recognized as a negative factor in the prognosis of pancreatic cancer.