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Introduction: Inhibition of programmed cell death-1 (PD-1) and its ligand programmed death ligand 1 (PD-L1) by using an immune checkpoint inhibitor has emerged as a promising immunotherapy for NSCLC. The correlation of PD-L1 expression in tumor cells with treatment outcomes has been reported in many pivotal trials; however, the relationship remains unclear. Here, we demonstrate that those patients with both high density of PD-1-positive CD8 and PD-L1-positive CD4-positive CD25-positive (PD-1 hi PD-L1 hi ) regulatory T cells (Tregs) have a better response to PD1/PD-L1 blockade., Methods: In our study between April 1, 2014, and May 30, 2017, a total of 73 NSCLC peripheral blood samples and fresh tumor specimens were collected for study. Of these, 42 large (10-mm 3 ) fresh tumor specimens were obtained from surgical procedures and checked for expression of immunology biomarkers, including PD-L1, PD-1, CD8, CD4, and CD25, in tumor cells and tumor-infiltrating lymphocytes (TILs) by flow cytometry, immunohistochemistry, and immunofluorescence (IF). Moreover, 31 small biopsy specimens from patients who received immunotherapy (pembrolizumab or nivolumab) were analyzed by immunohistochemistry and IF. The correlation between flow cytometry and IF detected for TILs' density was evaluated by Spearman's rank correlation test; the primary end point was progression-free survival. For the PD-1/PD-L1 blockade assay, the TILs and peripheral blood mononuclear CD8 T cells were cultured (1×10 5 per well) with anti-PD-1 (clone MIH4), anti-PD-L1 (clone MIH1). The cytotoxic activity of TILs in killing NSCLC cells after stimulation by anti-PD-1 and anti-PD-L1 was measured by a conventional 51 Cr release assay., Results: We first identified a population of high-PD-L1-expressing CD25-positive CD4-positive T cells (PD-L1 hi Tregs) in the tumor microenvironment. The frequency of PD-L1 hi Tregs was higher in tumor tissue (mean 48.6 ± 14.3% in CD25-positive CD3-positive CD4-positive T cells) than in blood (mean 35.4 ± 10.2% in CD25-positive CD3-positive CD4-positive T cells) and normal tissue (mean 38.6 ± 9.7% in CD25-positive CD3-positive CD4-positive T cells) (p < 0.05), as determined by flow cytometry. The frequency of PD-L1 hi Tregs was positively correlated with PD-1-positive CD8 in Tregs. In addition, the TILs from these patients (PD-1 hi PD-L1 hi ) showed PD-1/PD-L1 pathway dependence and could induce a greater killing effect of TILs by PD-1/PD-L1 blockade treatment. The patients with PD-L1-positive NSCLC with PD-1 hi PD-L1 hi TILs showed a better clinical outcome than those with a low frequency of PD-1 hi CD8 or PD-L1 hi Tregs (median progression-free survival not reached versus 2 months)., Conclusions: Our findings suggested that the density of PD-L1-positive CD4-positive CD25-positive Tregs in the tumor microenvironment can serve as a diagnostic factor to supplement PD-L1 expression in tumor cells and predict the response to PD-1/PD-L1 blockade immunotherapy in NSCLC., (Copyright © 2017 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Purpose: Although clinical studies have shown promise for targeting programmed cell death protein-1 (PD-1) and ligand (PD-L1) signaling in non-small cell lung cancer (NSCLC), the factors that predict which subtype patients will be responsive to checkpoint blockade are not fully understood. Experimental Design: We performed an integrated analysis on the multiple-dimensional data types including genomic, transcriptomic, proteomic, and clinical data from cohorts of lung adenocarcinoma public (discovery set) and internal (validation set) database and immunotherapeutic patients. Gene set enrichment analysis (GSEA) was used to determine potentially relevant gene expression signatures between specific subgroups. Results: We observed that TP53 mutation significantly increased expression of immune checkpoints and activated T-effector and interferon-γ signature. More importantly, the TP53/KRAS comutated subgroup manifested exclusive increased expression of PD-L1 and a highest proportion of PD-L1 + /CD8A + Meanwhile, TP53- or KRAS -mutated tumors showed prominently increased mutation burden and specifically enriched in the transversion-high (TH) cohort. Further analysis focused on the potential molecular mechanism revealed that TP53 or KRAS mutation altered a group of genes involved in cell-cycle regulating, DNA replication and damage repair. Finally, immunotherapeutic analysis from public clinical trial and prospective observation in our center were further confirmed that TP53 or KRAS mutation patients, especially those with co-occurring TP53/KRAS mutations, showed remarkable clinical benefit to PD-1 inhibitors. Conclusions: This work provides evidence that TP53 and KRAS mutation in lung adenocarcinoma may be served as a pair of potential predictive factors in guiding anti-PD-1/PD-L1 immunotherapy. Clin Cancer Res; 23(12); 3012-24. ©2016 AACR ., (©2016 American Association for Cancer Research.)

Programmed cell death protein-1 (PD-1) and ligand (PD-L1) provide an important escape mechanism from immune attack, and blockade therapy of these proteins show promising clinical benefits in many types of cancer. PD-L1 can be induced by interferon-gamma (IFN-γ), hypoxia, or toll-like receptor (TLR)-mediated pathways that confer adaptive immune resistance, or upregulated by oncogenic signals leading to constitutive expression and resulting in intrinsic immune resistance. The PD-1/PD-L1 checkpoint blockade, which targets regulatory pathways in T cells to overcome immune resistance, is correlated to PD-L1 expression pattern and the presence of tumor-infiltrating lymphocytes (TILs). Meanwhile, immunogenic mutation loads show significant response to checkpoint blockade, which is probably due to PD-1/L1 status and TIL content. Finally, the clinical strategies to design effective checkpoint-targeting immunotherapies are based on the classification of inducible/constitutive expression of PD-L1 and the presence of TILs. [ABSTRACT FROM AUTHOR]