Significance of TIM-3 Expression in Resected Esophageal Squamous Cell Carcinoma

Abstract

T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) is a promising checkpoint. However, its features and prognostic value remain undetermined in esophageal squamous cell carcinoma (ESCC). This study evaluated the prognostic value of TIM-3 expression and its relationship with programmed cell death 1 (PD-1) and CD8+ tumor-infiltrating lymphocytes (TILs) in patients with surgically resected ESCC. Expression levels of TIM-3, PD-1, and CD8+ TILs in ESCC were determined by immunohistochemistry. The association between clinicopathologic features or clinical outcomes and TIM-3 expression was analyzed. A total of 183 patients with ESCC who had undergone esophagectomy without implementation of neoadjuvant therapy at the Second Affiliated Hospital of Soochow University in Suzhou, China from January 2009 to December 2014 were included. PD-1 positivity (P=.032) and high CD8+ TIL density (P= .035) significantly correlated with positive TIM-3 expression. TIM-3 positivity was an independent risk factor for recurrence-free survival (RFS) (P < .001) and overall survival (OS) (P < .001). Subgroup analysis revealed that the TIM-3+PD-1+CD8 low group had the worst RFS and OS, whereas the TIM-3-PD-1-CD8 high group had the best RFS and OS (RFS: log-rank test P < .001; OS: log-rank test P < .001). Positive TIM-3 expression was associated with PD-1 positivity and high CD8+ TIL density and was an independent risk factor for RFS and OS in ESCC. Furthermore, the combination of TIM-3 and PD-1 expression or CD8+ TIL density could further stratify patients into different groups with distinct prognosis.