Tumor infiltrating Foxp3+ regulatory T‐cells are associated with recurrence in pathologic stage I NSCLC patients

BACKGROUND: Early stage lung cancer has a variable prognosis, and there are currently no markers that predict which patients will recur. This study examined the relation between tumor-regulatory T (Treg) cells and total tumor-infiltrating T-cell lymphocytes (TIL) to determine whether they correlated with recurrence. METHODS: The authors reviewed all patients in our tissue databank from 1996 to 2001 and identified 64 consecutive pathologic stage I non-small cell lung cancer (NSCLC) patients who had surgical resection and at least a 2.5 years disease-free follow-up or documented recurrence within 2 years. Immunohistochemical analyses were performed on paraffin-embedded lung cancer tissue and the relation between Treg cells, TIL, and disease-specific survival was determined. A risk index was devised deductively for various possible combinations of Treg cells and TIL. RESULTS: Treg cells and TIL were detected in 33 of 64 (51%) and 53 of 64 (83%) patients, respectively. When data were analyzed by using a Treg/TIL Combination Risk Index, patients with high-risk and intermediate-risk indices had hazard ratios of 8.2 (P = .007) and 3.3 (P = .109), respectively. CONCLUSIONS: Patients with stage I NSCLC who have a higher proportion of tumor Treg cells relative to TIL had a significantly higher risk of recurrence. These data may be useful, particularly if combined with a panel of tumor markers, to suggest at the time of diagnosis which patients with seemingly early-stage NSCLC will relapse.