Combined immunophenotyping of tumor-infiltrating lymphocytes as a prognostic factor in resected patients with non-small cell lung cancer.

11125 Background: Current evidence has highlighted the potential role for tumor infiltrating lymphocytes (TILs) in determining the survival of non-small cell lung cancer (NSCLC) patients. Whilst multiple studies have investigated the prognostic role of various subtypes of TILs, data is limited on the co-expression of TILs subpopulations and its clinical relevance. Identifying immune prognostic markers may help select postoperative NSCLC patients with a poorer prognosis for treatment with immunotherapy. We aim to identify NSCLC subgroups according to combined immunophenotypes and investigate their clinical relevance. Methods: A tissue microarray was constructed from 105 cases of resected NSCLC. Immunohistochemistry for TILs with CD3, CD8, FoxP3 and Granzyme B (GZMB) Ab was performed with an autostainer. TILs were quantified using the Vectra Automated Multispectral Imaging System. Low (-) and high (+) densities of TILs were dichotomised by the medians. EGFR and KRAS mutations were determined with Sanger sequencing. Clustering was performed using the heatmap function of R v3.0.2. Associations with clinicopathological variables were assessed by Chi-square analysis, and association with disease-specific survival (DSS) was performed using Cox proportional hazards model analysis. Results: The median age of patients was 64 years, 70% were male, 59% were stage I, and 57% of tumors were adenocarcinoma. Unsupervised clustering revealed 4 major subgroups based on the co-occurrence of high and low densities: FOXP3+/CD3+ (29% of cases), FOXP3+/CD3- (11%), FOXP3-/GZMB+ (28%) and FOXP3-/GZMB- (31%). The FOXP3+/CD3+ phenotype was significantly associated with squamous cell histology (p=0.047). There was no association with other features, including EGFR or KRAS mutation status. Patients with FOXP3+/CD3+ phenotype had a worse DSS (HR 2.17, 95% confidence interval [1.08-4.36], p=0.034) compared to those in other subgroups. Conclusions: Combined immunophenotyping suggests NSCLC may be comprised of four major subgroups. The FOXP3+/CD3+ phenotype may indicate a worse prognosis for patients with resected NSCLC and thus identify patients for immune directed adjuvant therapy.