Prognostic significance of tumor-infiltrating CD8⁺ or CD3⁺ T lymphocytes and interleukin-2 expression in radically resected non-small cell lung cancer.

Abstract

Background:Altered immunoresponse is associated with tumorigenesis and cancer progression. This study assessed the levels of tumor-infiltrating CD3+ or CD8+ T lymphocytes and interleukin-2 (IL-2) protein in radically resected non-small cell lung cancer (NSCLC) tissues to predict overall survival (OS) of the patients.Methods:Paraffin-embedded tissue specimens from 129 NSCLC patients were retrospectively collected for immunostaining of CD8+, CD3+, and IL-2 expression. Clinicopathological and survival data were collected and analyzed using the Chi-squared test, Kaplan–Meier curves, and the log-rank test or the Cox regression model.Results:The data showed a significant inverse association between CD8+ T lymphocyte levels and IL-2 expression (r = −0.927; P = 0.000) and between the levels of CD8+ and CD3+ T lymphocytes (r = −0.722; P = 0.000), but a positive association between CD3+ T lymphocyte levels and IL-2 expression (r = 0.781; P = 0.000) in NSCLC tissues. Furthermore, the levels of CD3+ and CD8+ T lymphocytes and IL-2 expression were associated with tumor stage (P = 0.023, 0.006, and 0.031, respectively) and the level of CD8+ T lymphocytes was associated with the patient gender (P = 0.024). In addition, the levels of CD8+ T lymphocytes were associated with an unfavorable 5-year OS, whereas patients with high levels of CD3+ T lymphocytes in tumor lesions and IL-2-expressing tumors had significantly better 5-year OS rates than patients with low levels.Conclusions:The levels of CD8+ T cells in tumor lesions and IL-2 expression were both independent predictors of OS for these NSCLC patients. Thus, the detection of tumor-infiltrating CD3+ or CD8+ T lymphocytes and IL-2 expression could be useful to predict the prognosis of radically resected NSCLC patients.