Prognostic significance of tumor-infiltrating lymphocytes in patients with operable tongue cancer

Background: Our aim was to investigate the prognostic significance of tumor-infiltrating lymphocytes (TILs) in operable tongue cancer patients. Methods: The presence of CD3(+), CD4(+), CD8(+), and forkhead box protein P3-positive (FOXP3(+)) TILs in tumor tissues obtained from 93 patients during surgery was examined using immunohistochemistry. Results: The 3-year overall survival (OS) of patients with a low CD8/FOXP3 ratio was significantly lower than that of patients with a high CD8/FOXP3 ratio (63.8% vs. 87.3%, p = 0.001). Patients with high FOXP3 had a significantly lower 3-year regional recurrence-free survival (RRFS) than did patients with low FOXP3 (49.3% vs. 87.3%, univariate log rank p = 0.000). A low CD4/FOXP3 ratio (68.4% vs. 93.7%, univariate log rank p = 0.002) was significantly unfavorable prognostic factors for 3-year distant metastasis-free survival (DMFS). Conclusions: In addition to clinicopathological characteristics, TIL markers represent prognosticators for clinical outcomes.