Prognostic value of programmed cell death-ligand 1 expression in patients with non-small-cell lung cancer: evidence from an updated meta-analysis

Platinum-based neoadjuvant chemotherapy upregulates STING/IFN pathway expression and promotes TILs infiltration in NSCLC

Objectives

To evaluate the effects of platinum-based neoadjuvant chemotherapy (NACT) on the STING/IFN pathway and tumor-infiltrating lymphocytes (TILs) in non-small cell lung cancer (NSCLC), as well as clinicopathological factors affecting patient survival.

Materials and methods

A total of 68 patients aged 34-77 years with NSCLC who received neoadjuvant chemotherapy and surgical treatment from March 2012 to February 2019 were reviewed, and the clinical pathological data and paired tissue specimens before and after NACT were collected. Immunohistochemistry and immunofluorescence were used to detect the protein levels of STING, PD-L1 and IFN-β, and the infiltration density of CD3+ TILs and CD8+TILs. The correlation between the expression of STING, PD-L1, IFN-β and the infiltration density of CD3+ TILs and CD8+ TILs as well as the clinicopathological characteristics before and after NACT was analyzed. The relationship between the related indexes, clinicopathological features and prognosis was also discussed.

Results

NACT increased the expression of STING, IFN-β and PD-L1 in tumor cells, and the infiltration of CD3+ and CD8+ TILs. In addition, ypTNM stage, ypN stage, changes in CD3+ TILs and in PD-L1 were associated with DFS (disease-free survival). CD3+ TILs changes and ypN stage were associated with OS (overall survival). Notably, ypN stage and CD3+ TILs changes were independent prognostic factors for DFS and OS.

Conclusion

NACT stimulates STING/IFN-β pathway, promotes infiltration of CD3+ and CD8+ TILs, triggers innate and adaptive immunity, and also upregulates PD-L1, which complemented the rationale for neoadjuvant chemotherapy in combination with immunotherapy. In addition, DFS was longer in patients with ypTNM I, ypN0-1, and elevated CD3+TILs after NACT. Patients with ypN0 and elevated CD3+ TILs after NACT had better OS benefits.

Conformance Assessment of PD-L1 Expression Between Primary Tumour and Nodal Metastases in Non-Small-Cell Lung Cancer

Introduction

Programmed death-ligand 1 (PD-L1) expression as measured by immunohistochemistry (IHC) has been employed to predict the efficacy of anti-PD-1/PD-L1 therapy. Nevertheless, heterogeneous PD-L1 expression represents a challenge for the selection of patients for anti-PD-1/PD-L1 therapy.

Methods

PD-L1 expression using clone 22C3 in 76 resected non-small-cell lung cancer and paired nodal metastases was assessed and classified according to the proportion of immunostained tumour cells using cutoff values of 1%, 5%, and 50%.

Results

The concordance rates for PD-L1 expression between primary and metastatic lymph nodes (N1) at these cutoff values were 67.7% (21/31) (Kappa value: 0.455, p<0.000), 60.0% (15/25) (Kappa value: 0.668, p<0.000), and 62.5% (5/8) (Kappa value: 0.497, p<0.000). In 36 paired N1 lymph nodes and N2 lymph nodes, 54.5% (6/11) (Kappa value: 0.625, p<0.000) of cases of PD-L1 expression were coincident at cutoffs of 1%. If stratified by adenocarcinoma and squamous cell carcinoma, 87.5% (14/16) (Kappa value: 0.830, p<0.000) of cases at the 1% cutoff and 46.7% (7/15) (Kappa value: 0.324, p<0.000) of cases at the 1% cutoff were coincident.

Conclusion

The results of this study demonstrate that the concordance of PD-L1 expression between primary tumour and nodal metastases is low in non-small-cell lung cancer but is high in adenocarcinoma. Our results also suggest that PD-L1 expression in either lymph nodes or tumour tissues does not predict survival. PD-L1 detection in metastatic lymph nodes is not a suitable replacement for PD-L1 detection in the primary lesion.

Indoleamine-2,3-Dioxygenase in Non-Small Cell Lung Cancer: A Targetable Mechanism of Immune Resistance Frequently Coexpressed With PD-L1

The immune regulatory enzyme indoleamine-2,3-dioxygenase (IDO-1) suppresses T cell responses and may reduce efficacy of therapies targeting immune checkpoints such as programmed death receptor-1/programmed death ligand-1 (PD-1/PD-L1). Early phase clinical trials combining IDO-1 and PD-1/PD-L1 inhibitors have shown some promise in non-small cell lung cancers (NSCLCs). However, the coexpression of IDO-1 and PD-L1 has not been thoroughly investigated, and the potential for IDO-1 immunohistochemical expression as a therapeutic biomarker is unknown. One hundred two cases of NSCLC (51 adenocarcinomas, 9 adenosquamous carcinomas, and 42 squamous cell carcinomas) were evaluated for IDO-1 and PD-L1 expression by immunohistochemistry. IDO-1 expression was identified in 43% of NSCLC (42% of adenocarcinomas, 44% of adenosquamous carcinomas, and 43% of squamous cell carcinomas). Coexpression with PD-L1 (≥1%) was common (27% overall; 27% of adenocarcinomas, 33% of adenosquamous carcinomas, and 26% of squamous cell carcinomas). A smaller population of tumors showed isolated PD-L1 (25% overall; 16% of adenocarcinomas, 44% of adenosquamous carcinomas, and 33% of squamous cell carcinomas) or IDO-1 expression (15% overall; 14% of adenocarcinomas, 11% of adenosquamous carcinomas, and 17% of squamous cell carcinomas). In summary, IDO-1 is commonly expressed by NSCLC, and its frequent coexpression with PD-L1 may account for the increased efficacy seen with dual blockade of PD-1/PD-L1 and IDO in clinical studies. IDO-1 immunohistochemistry may be a useful biomarker for selection of patients who could benefit from dual-agent therapy and should be evaluated in prospective clinical trials using PD-1/PD-L1 and IDO inhibitors.

Detection of PD-L1 in circulating tumor cells and white blood cells from patients with advanced non-small-cell lung cancer

Background

Expression of PD-L1 in tumor cells and tumor-infiltrating immune cells has been associated with improved efficacy to anti-PD-1/PD-L1 inhibitors in patients with advanced-stage non-small-cell lung cancer (NSCLC) and emerged as a potential biomarker for the selection of patients to cancer immunotherapies. We investigated the utility of circulating tumor cells (CTCs) and circulating white blood cells (WBCs) as a noninvasive method to evaluate PD-L1 status in advanced NSCLC patients.

Patients and methods

CTCs and circulating WBCs were enriched from peripheral blood samples (ISET® platform; Rarecells) from 106 NSCLC patients. PD-L1 expression on ISET filters and matched-tumor tissue was evaluated by automated immunostaining (SP142 antibody; Ventana), and quantified in tumor cells and WBCs.

Results

CTCs were detected in 80 (75%) patients, with levels ranging from 2 to 256 CTCs/4 ml, and median of 60 CTCs/4 ml. Among 71 evaluable samples with matched-tissue and CTCs, 6 patients (8%) showed ≥1 PD-L1-positive CTCs and 11 patients (15%) showed ≥1% PD-L1-positive tumor cells in tumor tissue with 93% concordance between tissue and CTCs (sensitivity = 55%; specificity = 100%). From 74 samples with matched-tissue and circulating WBCs, 40 patients (54%) showed ≥1% PD-L1-positive immune infiltrates in tumor tissue and 39 patients (53%) showed ≥1% PD-L1 positive in circulating WBCs, with 80% concordance between blood and tissue (sensitivity = 82%; specificity = 79%). We found a trend for worse survival in patients receiving first-line cisplatin-based chemotherapy treatments, whose tumors express PD-L1 in CTCs or immune cells (progression-free and overall survival), similar to the effects of PD-L1 expression in matched-patient tumors.

Conclusions

These results demonstrated that PD-L1 status in CTCs and circulating WBCs correlate with PD-L1 status in tumor tissue, revealing the potential of CTCs assessment as a noninvasive real-time biopsy to evaluate PD-L1 expression in patients with advanced-stage NSCLC.

PD-L1 Expression in Non-Small-Cell Lung Cancer Including Various Adenocarcinoma Subtypes

PURPOSE

Knowledge regarding programmed death-ligand 1 (PD-L1) expression in lung cancer is limited. We aim to clarify PD-L1-positive expression in non-small-cell lung cancer (NSCLC), including adenocarcinoma subtypes.

METHODS

In all, 90 NSCLC specimens containing various adenocarcinoma subtypes, in addition to squamous cell carcinoma and large-cell carcinoma were selected. PD-L1 was immunohistochemically stained by murine monoclonal antibody clone 22C3.

RESULTS

When PD-L1-positive expression was defined by tumor proportion score (TPS) ≥1%, the positive cases were 0/11 in adenocarcinoma in situ, 0/12 in minimally invasive adenocarcinoma, 1/10 in lepidic predominant adenocarcinoma, 1/13 in papillary predominant adenocarcinoma, 8/14 in acinar predominant adenocarcinoma, 6/11 in solid predominant adenocarcinoma, 0/3 in micropapillary predominant adenocarcinoma, 0/4 in invasive mucinous adenocarcinoma, 4/9 in squamous cell carcinoma, and 2/3 in large-cell carcinoma. PD-L1 positivity was higher in males, smokers, advanced pathologic stages, positive vessel invasion, and positive lymphatic invasion. Postoperative survival analysis revealed that PD-L1-positive expression was a significantly worse prognostic factor in univariate analysis for recurrence-free survival (RFS).

CONCLUSION

PD-L1-positive tumors were frequent in acinar predominant adenocarcinoma and solid predominant adenocarcinoma than other adenocarcinoma subtypes. PD-L1 expression seemed to increase according to pathologic tumor progression, suggesting a worse postoperative prognosis in NSCLC patients.

Role of PD-L1 Expression in Non-Small Cell Lung Cancer and Their Prognostic Significance according to Clinicopathological Factors and Diagnostic Markers

Background: The latest immunotherapy, used in the treatment of non-small cell lung cancer (NSCLC), uses monoclonal antibodies directed against programmed death ligand 1 (PD-L1) to inhibit its interaction with the PD-1 receptor. Elevated levels of PD-L1 expression were observed on NSCLC cells. The association between PD-L1 expression and clinicopathological features is still unclear. Therefore, we examined this relationship and also compare PD-L1 expression levels with Ki-67, p63 and TTF-1. Methods: 866 samples of NSCLCs were used to prepare tissue microarrays (TMAs) on which immunohistochemical (IHC) reactions were performed. Changes in the level of CD274 (PD-L1) gene expression in 62 NSCLC tumors were tested in relation to 14 normal lung tissues by real-time PCR reactions (RT-PCR). Results: PD-L1 expression was observed in 32.6% of NSCLCs. PD-L1 expression was increased in higher malignancy grades (G) (p < 0.0001) and in higher lymph node status (pN) (p = 0.0428). The patients with low PD-L1 expression had longer overall survival compared to the group with high expression (p = 0.0332) in adenocarcinoma (AC) only. Conclusions: PD-L1 expression seems to be associated with increased tumor proliferation and aggressiveness as well as shorter patient survival in NSCLC, predominantly in the AC group.

Prognostic Impact of Tumor Cell Programmed Death Ligand 1 Expression and Immune Cell Infiltration in NSCLC

INTRODUCTION

Infiltration of T and B/plasma cells has been linked to NSCLC prognosis, but this has not been thoroughly investigated in relation to the expression of programmed death ligand 1 (PD-L1). Here, we determine the association of lymphocytes and PD-L1 with overall survival (OS) in two retrospective cohorts of operated NSCLC patients who were not treated with checkpoint inhibitors targeting the programmed death 1/PD-L1 axis. Moreover, we evaluate how PD-L1 positivity and clinicopathologic factors affect the prognostic association of lymphocytes.

METHODS

Cluster of differentiation (CD) 3 (CD3)-, CD8-, CD4-, forkhead box P3 (FOXP3)-, CD20-, CD79A-, and immunoglobulin kappa constant (IGKC)-positive immune cells, and tumor PD-L1 positivity, were determined by immunohistochemistry on tissue microarrays (n = 705). Affymetrix data was analyzed for a patient subset, and supplemented with publicly available transcriptomics data (N = 1724). Associations with OS were assessed by Kaplan-Meier plots and uni- and multivariate Cox regression.

RESULTS

Higher levels of T and B plasma cells were associated with longer OS (p = 0.004 and p < 0.001, for CD8 and IGKC, respectively). Highly proliferative tumors with few lymphocytes had the worst outcome. No association of PD-L1 positivity with OS was observed in a nonstratified patient population; however, a significant association with shorter OS was observed in never-smokers (p = 0.009 and p = 0.002, 5% and 50% cutoff). Lymphocyte infiltration was not associated with OS in PD-L1-positive tumors (50% cutoff). The prognostic association of lymphocyte infiltration also depended on the patients' smoking history and histologic subtype.

CONCLUSIONS

Proliferation, PD-L1 status, smoking history, and histology should be considered if lymphocyte infiltration is to be used as a prognostic biomarker.

High PD-L1 expression in the tumour cells did not correlate with poor prognosis of patients suffering for oral squamous cells carcinoma: A meta-analysis of the literature

OBJECTIVES

Oral cancer represents one of the most common malignancies in humans. Its prognosis is still poor, despite the most recent improvements in therapies. An increasing attention is placed on the role of programmed death ligand 1 (PD-L1) in the tumour immunity and its potential function as a marker for tumour prognosis. Whether PD-L1 expression is a prognostic factor for the poor outcomes in oral squamous cell carcinoma is still controversial. This study aimed to investigate, through a meta-analysis, a potential correlation between PD-L1 expression and the prognostic outcomes in patients with oral squamous cell carcinoma.

MATERIALS AND METHODS

The studies were identified by searching PubMed, SCOPUS, Web of Science and were assessed by two of the authors. After the selection process, 11 articles met eligibility criteria and were included in the meta-analysis. Quality assessment of studies was performed according to the REMARK guidelines, and the risk of biases across studies was investigated through Q and I² tests. Meta-analysis was performed to investigate the association between the PD-L1 expression either overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS), gender and lymph node metastasis.

RESULTS

A total of 1060 patients were analysed in the 11 studies included in the meta-analysis. Pooled analysis revealed that the expression of PD-L1 did not correlate with poor OS (HR, 0.60; 95% CI: [0.33, 1.10]; P = 0.10), DFS (HR, 0.62; 95% CI: [0.21, 1.88]; P = 0.40), DSS (HR, 2.05; 95% CI: [0.53, 7.86]; P = 0.29 and lymph node metastasis (HR, 1.15; 95% CI: [0.74, 1.81]; P = 0.53). Furthermore, results of the meta-analysis showed that high expression of PD-L1 is two times more frequent in female patients (OR, 0.5; 95% CI: [0.36, 0.69]; P < 0.0001) compared to males. For all the three outcomes analysed, a high rate of heterogeneity was detected (I²  > 50%).

DISCUSSION

High PD-L1 expression did not correlate with poor prognosis of patients suffering for oral squamous cell carcinoma. Studies published on the topic showed a significant variation in results, limiting the use of PD-L1 expression by immunohistochemistry as prognostic biomarker in clinical practice.

Stratification of ovarian tumor pathology by expression of programmed cell death-1 (PD-1) and PD-ligand- 1 (PD-L1) in ovarian cancer

BACKGROUND

Ovarian cancer is the major cause of death among gynecologic cancers with 75% of patients diagnosed with advanced disease, and only 20% of these patients having a survival duration of five years. Treatments blocking immune checkpoint molecules, programmed cell death (PD-1) or its ligand PD-ligand- I (PD-L1) have produced a beneficial and prolonged effect in a subgroup of these patients. However, there is debate in the literature concerning the prognostic value of the expression of these molecules in tumors, with immunotherapy responsiveness, and survival. We evaluated the immune landscape of the ovarian tumor microenvironment of patients, by measuring the impact of the expression of tumor PD-1, PD-L1 and infiltrating lymphocytes on stage and grade of tumors and survival, in a cohort of 55 patients with gynecologic malignancies. Most patients under study were diagnosed with advanced disease ovarian cancer.

RESULTS

Our studies revealed that a low density of PD-1 and of PD-L1 expressing cells in tumor tissue were significantly associated with advanced disease (P = 0.028 and P = 0.033, respectively). Moreover, PD-L1 was expressed significantly more often in high grade tumors (41.5%) than in low grade tumors of patients (7.7%) (P = 0.040). The presence of CD3 or of FoxP3 infiltrating cells with PD-L1 in patient tumors did not impact the significance of the association of PD-L1 with high grade tumors (P = 0.040), and our analyses did not show an association between the presence of PD-1 or PD-L1 and survival.

CONCLUSIONS

We conclude that a subgroup of advanced disease ovarian cancer patients with high grade tumors, expressing PD-L1, may be prime candidates for immunotherapy targeting PD-1 signaling.

Stratification of ovarian tumor pathology by expression of programmed cell death-1 (PD-1) and PD-ligand- 1 (PD-L1) in ovarian cancer

Background

Ovarian cancer is the major cause of death among gynecologic cancers with 75% of patients diagnosed with advanced disease, and only 20% of these patients having a survival duration of five years. Treatments blocking immune checkpoint molecules, programmed cell death (PD-1) or its ligand PD-ligand- I (PD-L1) have produced a beneficial and prolonged effect in a subgroup of these patients. However, there is debate in the literature concerning the prognostic value of the expression of these molecules in tumors, with immunotherapy responsiveness, and survival.

We evaluated the immune landscape of the ovarian tumor microenvironment of patients, by measuring the impact of the expression of tumor PD-1, PD-L1 and infiltrating lymphocytes on stage and grade of tumors and survival, in a cohort of 55 patients with gynecologic malignancies. Most patients under study were diagnosed with advanced disease ovarian cancer.

Results

Our studies revealed that a low density of PD-1 and of PD-L1 expressing cells in tumor tissue were significantly associated with advanced disease (P = 0.028 and P = 0.033, respectively). Moreover, PD-L1 was expressed significantly more often in high grade tumors (41.5%) than in low grade tumors of patients (7.7%) (P = 0.040). The presence of CD3 or of FoxP3 infiltrating cells with PD-L1 in patient tumors did not impact the significance of the association of PD-L1 with high grade tumors (P = 0.040), and our analyses did not show an association between the presence of PD-1 or PD-L1 and survival.

Conclusions

We conclude that a subgroup of advanced disease ovarian cancer patients with high grade tumors, expressing PD-L1, may be prime candidates for immunotherapy targeting PD-1 signaling.

Electronic supplementary material

The online version of this article (10.1186/s13048-018-0414-z) contains supplementary material, which is available to authorized users.

Stratification of ovarian tumor pathology by expression of programmed cell death-1 (PD-1) and PD-ligand- 1 (PD-L1) in ovarian cancer

BACKGROUND

Ovarian cancer is the major cause of death among gynecologic cancers with 75% of patients diagnosed with advanced disease, and only 20% of these patients having a survival duration of five years. Treatments blocking immune checkpoint molecules, programmed cell death (PD-1) or its ligand PD-ligand- I (PD-L1) have produced a beneficial and prolonged effect in a subgroup of these patients. However, there is debate in the literature concerning the prognostic value of the expression of these molecules in tumors, with immunotherapy responsiveness, and survival. We evaluated the immune landscape of the ovarian tumor microenvironment of patients, by measuring the impact of the expression of tumor PD-1, PD-L1 and infiltrating lymphocytes on stage and grade of tumors and survival, in a cohort of 55 patients with gynecologic malignancies. Most patients under study were diagnosed with advanced disease ovarian cancer.

RESULTS

Our studies revealed that a low density of PD-1 and of PD-L1 expressing cells in tumor tissue were significantly associated with advanced disease (P = 0.028 and P = 0.033, respectively). Moreover, PD-L1 was expressed significantly more often in high grade tumors (41.5%) than in low grade tumors of patients (7.7%) (P = 0.040). The presence of CD3 or of FoxP3 infiltrating cells with PD-L1 in patient tumors did not impact the significance of the association of PD-L1 with high grade tumors (P = 0.040), and our analyses did not show an association between the presence of PD-1 or PD-L1 and survival.

CONCLUSIONS

We conclude that a subgroup of advanced disease ovarian cancer patients with high grade tumors, expressing PD-L1, may be prime candidates for immunotherapy targeting PD-1 signaling.

Effect of mutant variants of the KRAS gene on PD-L1 expression and on the immune microenvironment and association with clinical outcome in lung adenocarcinoma patients

OBJECTIVES

The effect of anti-PD-1/PD-L1 inhibitors on lung adenocarcinomas (LADCs) with KRAS mutations is debatable. We examined the association between specific mutant KRAS proteins and the immune infiltrates with the outcome of patients with LADCs.

PATIENTS AND METHODS

In 219 LADCs harboring either wild-type (WT) or mutated KRAS gene, we quantified the density of several immune markers by immunohistochemistry followed by automated digital image analysis. Data were correlated to clinicopathological parameters and outcome of patients.

RESULTS

Tumors harboring mutant KRAS-G12 V had a significantly higher PD-L1 expression compared to other tumors (p = 0.044), while mutant KRAS-G12D tumors showed an increase in the density of CD66b+ cells (p = 0.001). High PD-L1 expression in tumor cells was associated to improved overall survival (OS) in KRAS mutant patients (p = 0.012), but not in the WT population (p = 0.385), whereas increased PD-L1 expression in immune cells correlated to poor OS of KRAS-WT patients (p = 0.025), with no difference in patients with KRAS mutations.

CONCLUSIONS

KRAS mutational status can affect the immune microenvironment and survival of LADC patients in a heterogeneous way, implying that specific mutant KRAS variants expressed by the tumor should be considered when stratifying patients for immunotherapy.

Prognostic significance of immune cells in non-small cell lung cancer: meta-analysis

Background

Tumor-associated immune cells are prognostic in non-small cell lung cancer (NSCLC) but findings have been conflicting.

Objectives

To determine the prognostic role of immune cells according to localization in NSCLC patients.

Methods

A systematic literature review and meta-analysis was performed on dendritic cell (DC), tumor associated macrophages (TAM), mast cells (MC), natural killer (NK) cells, T and B cells and tumor CTLA-4 and PD-L1 studies.

Results

We analysed 96 articles (n= 21,752 patients). Improved outcomes were seen with increased tumor DCs (overall survival (OS) hazard ratio (HR) 0.55; 95% confidence interval (CI) 0.44-0.68), NK cells (OS HR 0.45; 0.31-0.65), TAMs (OS HR 0.33; 0.17-0.62), M1 TAMs (OS HR 0.10; 0.05-0.21), CD3+ T cells (disease specific survival (DSS) HR 0.64; 0.48-0.86), CD8+ T cells (OS HR 0.78; 0.66-0.93), B cells (OS HR 0.65; 0.42-0.99) and with increased stroma DC (DSS HR 0.62; 0.47-0.83), NK cells (DSS HR 0.51; 0.32-0.82), M1 TAMs (OS HR 0.63; 0.42-0.94), CD4+ T cells (OS HR 0.45; 0.21-0.94), CD8+ T cells (OS HR 0.77; 0.69-0.86) and B cells (OS HR 0.74;0.56-0.99). Poor outcomes were seen with stromal M2 TAMs (OS HR 1.44; 1.06-1.96) and Tregs (relapse free survival (RFS) HR 1.80; 1.34-2.43). Tumor PD-L1 was associated with worse OS (1.40; 1.20-1.69), RFS (1.67) and DFS (1.24).

Conclusion

Tumor and stroma DC, NK cells, M1 TAMs, CD8+ T cells and B cells were associated with improved prognosis and tumor PD-L1, stromal M2 TAMs and Treg cells had poorer prognosis. Higher quality studies are required for confirmation.

Prognostic Value of PD-L1 mRNA Sequencing Expression Profile in Non-Small Cell Lung Cancer

BACKGROUND

Immune checkpoint inhibitors that target the programmed cell death protein ligand 1 (PD-L1) pathway have shown benefit for the treatment of metastatic non-small cell lung cancer (NSCLC). However, the prognostic value of PD-L1 independent of immunotherapy is still unclear, with conflicting results reported between PD-L1 expression and patient survival. Our aim was to correlate PD-L1 mRNA level with clinical and pathologic factors and to investigative the prognostic value of PD-L1 mRNA in all stages of NSCLC.

METHODS

Gene expression and clinical data were obtained from public repositories in The Cancer Genome Atlas from the National Cancer Institute. Genotype-Tissue Expression was used to compare with normal tissue expression analysis.

RESULTS

A total of 985 patients met inclusion criteria, among whom 79.6% were stage I to II, 16.5% were stage III, and 3.5% were stage IV, representing 495 adenocarcinoma and 490 squamous cell carcinoma (SCC). PD-L1 mRNA gene expression in lung cancers was higher than in most other tumor and normal tissue types and was significantly higher in lung SCC than adenocarcinoma (p < 0.001). PD-L1 mRNA expression was associated with pathologic stage in SCC and with smoking status in adenocarcinoma of the lung. However, none of the cutoff values of PD-L1 mRNA expression were prognostic of overall survival.

CONCLUSIONS

Our results suggest that the value of PD-L1 mRNA in prognosticating outcome in lung cancer is limited. Further studies are needed to identify novel prognostic biomarkers other than PD-L1 that are associated with improved patient survival. Identification of further prognostically important biomarkers may prove useful in identifying patients suitable for immunotherapy.

Assessment of programmed cell death ligand-1 expression with multiple immunohistochemistry antibody clones in non-small cell lung cancer

Background

Programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) have been identified as novel targets for immunotherapy, with PD-L1 as a potential predictive biomarker. However, a specific antibody for PD-L1 expression is an immediate requirement. Meanwhile, the clinicopathological identification of patients with positive PD-L1 remains unclear.

Methods

The present study adopted three anti-PD-L1 IHC antibodies, SP142, SP263, and UMAB228 to test PD-L1 expression in 84 non-small cell lung cancer (NSCLC) specimens. The concordance among antibodies was examined by analytical comparison, and the association between PD-L1 expression and clinicopathological factors was assessed.

Results

The samples from 41 (48.8%), 51 (60.7%), and 50 (59.5%) patients were detected as PD-L1 positive evaluated by antibody SP142, SP263, and UMAB228, respectively. The kappa coefficient was 0.53, 0.58, and 0.46 for SP263 vs. SP142, SP263 vs. UMAB228, and SP142 vs. UMAB228, respectively. On the other hand, the univariate analysis of consensus cases indicated that the PD-L1 expression was significantly correlated with tobacco use (χ²=4.25, P=0.04).

Conclusions

The analytical comparison showed moderate concordance between SP142, SP263 and UMAB228, whereas SP263 exhibited higher overall positive rate. Moreover, PD-L1 positive rate was significantly higher in patients with smoking history, which might help in identifying patients who would benefit from PD-1/PD-L1 checkpoint inhibitors.

Prognostic Role of Programmed Death Ligand-1 Expression in Breast Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Cancer therapies that target the PD-1/PD-L1 pathway are in ongoing phase I/II clinical trials for several tumor types. However, the prognostic value of PD-L1 expression in breast cancer is unclear.

OBJECTIVE

We assessed the prognostic role of PD-L1 expression in breast cancer.

METHODS

We searched Medline/PubMed for eligible studies of the association between PD-L1 expression and patient survival in breast cancer published before 7 December 2015. The effect size was the hazard ratio (HR) with 95 % confidence interval (CI) for overall survival (OS), recurrence-free survival (RFS) and metastasis-free survival (MFS). Odds ratios (OR) with 95 % CIs were also extracted to evaluate associations between PD-L1 expression and patient clinicopathological features.

RESULTS

We included five studies with 7,802 total patients in this meta-analysis. The pooled OR associated high PD-L1 expression with predictors of poor-prognosis: high tumor grade, negative ER status, negative PR status, positive HER2 status and lymphovascular invasion. High PD-L1 protein expression was associated with shorter OS (HR = 3.22, 95 % CI: 1.86-5.59; P < 0.0001), shorter RFS (HR = 1.38, 95 % CI: 1.03-1.86; P = 0.03) and shorter MFS (HR = 3.33, 95 % CI: 2.30-4.82; P < 0.00001); whereas high PD-L1 mRNA expression was associated with longer OS (HR = 0.86, 95 % CI: 0.75-1.00; P = 0.05) and longer RFS (HR = 0.57, 95 % CI: 0.36-0.91; P = 0.02).

LIMITATIONS

The findings of these studies were significantly heterogeneous; the results should be interpreted cautiously.

CONCLUSION

In breast cancer, high PD-L1 protein expression appears to be a negative prognostic factor, whereas high PD-L1 mRNA expression appears to be a favorable prognostic factor.

The correlation between programmed death-ligand 1 expression and driver gene mutations in NSCLC

OBJECTIVES

This study aimed to evaluate the correlation between positive PD-L1 expression and driver gene mutations in NSCLC and to seek preliminary evidence in favor of the strategy of PD-L1 inhibitors plus targeted agents.

RESULTS

The overall analyses revealed that positive PD-L1 expression had a significant relationship with KRAS status (RR = 1.26; 95% CI, 1.06-1.50, P = 0.010), but no correlation with clinical characteristics (gender, smoking status, histological types), driver gene status (EGFR, ALK) and overall survival (OS): male versus female (RR = 1.16; 95% CI, 0.95-1.42; P = 0.15), never smoking versus former/current smoking (RR = 0.79; 95% CI, 0.56-1.11; P = 0.17), adenocarcinoma versus non-adenocarcinoma (RR = 0.94; 95% CI, 0.63-1.41; P = 0.77), EGFR mutation versus EGFR wild type (RR = 0.74; 95% CI, 0.52-1.06; P = 0.10), ALK positive versus ALK negative (RR = 1.02; 95% CI, 0.75-1.38; P = 0.91), OS of positive PD-L1 expression versus that of negative PD-L1 expression (HR = 1.31, 95% CI, 0.90-1.90; P = 0.15), respectively. Noteworthily, subgroup analyses exhibited that in Chinese cohort studies, positive PD-L1 expression was significantly correlated with OS (HR = 1.75, 95% CI, 1.36-2.24, P < 0.0001); and in the studies using PD-L1 monoclonal antibodies (McAbs), positive PD-L1 expression was significantly correlated with KRAS mutation (RR = 1.32, 95% CI, 1.06-1.65, P = 0.01) and EGFR mutation (RR = 0.51, 95% CI, 0.28-0.93, P = 0.03).

MATERIALS AND METHODS

After thoroughly searching PubMed, EMBASE and Cochrane Library databases, 11 relevant studies incorporating 3128 cases were identified. The pooled data were analyzed via Review manager 5.3 software.

CONCLUSIONS

PD-L1 inhibitors probably was a potential promising option to manage advanced NSCLC harboring KRAS mutation.

Correlation of cancer stem cell markers and immune cell markers in resected non-small cell lung cancer

Background: Recent studies confirmed that immunotherapy showed prominent efficacy in non-small cell lung cancer (NSCLC). Cancer stem cells/cancer initiating cells are resistant to anticancer treatment. The purpose of the study was to analyze the correlation of cancer stem cells/cancer initiating cells and tumor-infiltrating immune cells in NSCLC.

Methods: CD133, octamer 4 (OCT-4), CD8, CD56, human leukocyte antigen (HLA) class I and programmed death ligand-1 (PD-L1) were assessed in 172 resected NSCLC samples. The staining was analyzed and scored by the pathologist who was blinded to the clinical pathological data of the patients.

Results: High CD8+ T cell infiltration was correlated significantly with squamous cell carcinoma histology (p=0.008). High PD-L1 expression (≥10%) was associated with high tumor status (p=0.043). Pearson's correlation test showed that CD56+ cells were negatively correlated with CD133 expression (r=-0.361, p<0.001) and weakly correlated with negative OCT-4 expression (r=-0.180, p=0.018). There was a strong positive correlation between CD8 and HLA class I (r=0.573, p<0.001). In the survival analysis, high CD8+ T cell infiltration is an independent predictor of improved disease-free survival and overall survival. Patients with low CD133 expression and high CD56 expression had a longer overall survival than those with high CD133 expression and/or low CD56 expression (p=0.013).

Conclusion: There is a negative correlation between CD56+ cells and cancer stem cell markers. This correlation may confirm the possibility that natural killer cells can target CD133+ cancer stem cells/cancer initiating cells in non-small cell lung cancer.

PD-L1 expression in lung cancer and its correlation with driver mutations: a meta-analysis

Although many studies have addressed the prognostic value of programmed cell death-ligand 1 (PD-L1) expression in lung cancer, the results remain controversial. A systematic search of the PubMed, EMBASE, and Cochrane Library databases was performed to identify the correlation between PD-L1 expression and driver mutations and overall survival (OS). This meta-analysis enrolled a total of 11,444 patients for 47 studies, and the pooled results showed that increased PD-L1 expression was associated with poor prognosis (HR = 1.40, 95% CI: 1.19-1.65, P < 0.001). In subgroup analysis stratified according to histology types, the pooled results demonstrated that increased PD-L1 expression was an unfavorable prognostic factor for non-small cell lung cancer (NSCLC) (HR = 1.26, 95% CI: 1.05-1.52, P = 0.01) and pulmonary lymphoepithelioma-like carcinoma (LELC) (HR = 3.04, 95% CI: 1.19-7.77, P = 0.02), rather than small cell lung cancer (SCLC) (HR = 0.62, 95% CI: 0.27-1.39, P = 0.24). The pooled ORs indicated that PD-L1 expression was associated with gender, smoking status, histology, differentiation, tumour size, lymph nodal metastasis, TNM stage and EGFR mutation. However, PD-L1 expression was not correlated with ALK rearrangement and KRAS mutations.

Prognostic value of programmed cell death ligand 1 expression in patients with head and neck cancer: A systematic review and meta-analysis

Background

Programmed cell death ligand 1 (PD-L1) expression was reported to be correlated with poor prognosis in various cancers. However, the relationship between PD-L1 expression and the survival of patients with head and neck cancer (HNC) remains inconclusive. In the present study, we aimed to clarify the prognostic value of PD-L1 in HNC patients using meta-analysis techniques.

Methods

A comprehensive database searching was conducted in the PubMed, EMBASE, Web of Science and Cochrane Library from inception to August 2016. Studies meeting the inclusion criteria were included. The methodological quality of included studies was assessed by the Newcastle-Ottawa quality assessment scale. Hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs) were pooled by STATA 11.0 for the outcome of overall survival (OS) and disease-free survival (DFS).

Results

A total of 17 studies with 2,869 HNC patients were included in the meta-analysis. The results of meta-analysis showed that there was no significant correlation between PD-L1 expression and OS (HR, 1.23; 95% CI, 0.99–1.53; P = 0.065) or DFS (HR, 1.42; 95% CI, 1.00–2.03; P = 0.052) of HNC patients. However, the subgroup analysis suggested that positive expression of PD-L1 was associated with poor OS (HR, 1.38; 95% CI, 1.12, 1.70; P = 0.003) and DFS (HR, 1.99; 95% CI, 1.59, 2.48; P = 0.001) in HNC patients from Asian countries/regions. The subgroup analysis also showed that the correlations between PD-L1 and prognosis are variant among different subtypes of HNC. When performing sensitive analyses, we found that the results of meta-analyses were not robust.

Conclusion

The meta-analysis indicated that positive expression of PD-L1 could serve as a good predictor for poor prognosis of Asian patients with HNC. However, the findings still need to be confirmed by large-scale, prospective studies.

Practical Immuno-PET Radiotracer Design Considerations for Human Immune Checkpoint Imaging

Immune checkpoint blockade has emerged as a promising cancer treatment paradigm. Unfortunately, there are still a large number of patients and malignancies that do not respond to therapy. A major barrier to validating biomarkers for the prediction and monitoring of responders to clinical checkpoint blockade has been the lack of imaging tools to accurately assess dynamic immune checkpoint expression. Here, we sought to optimize noninvasive immuno-PET imaging of human programmed death-ligand 1 (PD-L1) expression, in a preclinical model, using a small high-affinity engineered protein scaffold (HAC-PD1). Six HAC-PD1 radiotracer variants were developed and used in preclinical imaging and biodistribution studies to assess their ability to detect human PD-L1 expression in vivo. Radiotracer design modifications included chelate, glycosylation, and radiometal. HACA-PD1 was adopted as the naming convention for aglycosylated tracer variants. NOD scid γ-(NSG) mice were inoculated with subcutaneous tumors engineered to either be constitutively positive (CT26 hPD-L1) or be negative (ΔmPD-L1 CT26) for human PD-L1 expression. When the tumors had grown to an average size of 1 cm in diameter, mice were injected with 0.75-2.25 MBq (∼10 μg) of an engineered radiotracer variant and imaged. At 1 h after injection, organs were harvested for biodistribution. Of the practical immuno-PET tracer modifications considered, glycosylation was the most prominent design factor affecting tracer uptake, specificity, and clearance. In imaging studies, aglycosylated ⁶⁴Cu-NOTA-HACA-PD1 most accurately visualized human PD-L1 expression in vivo. We reasoned that because of the scaffold's small size (14 kDa), its pharmacokinetics may be suitable for labeling with the short-lived and widely clinically available radiometal ⁶⁸Ga. At 1 h after injection, ⁶⁸Ga-NOTA-HACA-PD1 and ⁶⁸Ga-DOTA-HACA-PD1 exhibited promising target-to-background ratios in ex vivo biodistribution studies (12.3 and 15.2 tumor-to-muscle ratios, respectively). Notably, all HAC-PD1 radiotracer variants enabled much earlier detection of human PD-L1 expression (1 h after injection) than previously reported radiolabeled antibodies (>24 h after injection). This work provides a template for assessing immuno-PET tracer design parameters and supports the translation of small engineered protein radiotracers for imaging human immune checkpoints.

Assessing PDL-1 and PD-1 in Non-Small Cell Lung Cancer: A Novel Immunoscore Approach

INTRODUCTION

Immune checkpoint inhibitors targeting programmed cell death protein 1 (PD-1) or its ligand, PD-L1, have gained momentum in the treatment of non-small cell lung cancer (NSCLC). However, their prognostic significance remains controversial. The present study evaluated the expression of PD-L1 and PD-1 and their potential role in an Immunoscore, supplementing the TNM classification of NSCLC.

MATERIALS AND METHODS

Tissue microarrays constructed from tumor tissue samples from 2 cohorts of a total of 536 patients (University Hospital of North Norway, n = 285; Nordland Hospital, n = 251) with primary resected stage I to IIIA NSCLC. PD-L1 and PD-1 were evaluated by immunohistochemistry in the primary tumor and metastatic lymph node tissue.

RESULTS

In univariate analysis, a high density of PD-L1⁺ immune cells in the stromal compartment (S-PD-L1) and PD-1⁺ intraepithelial tumor infiltrating lymphocytes (T-PD-1) was associated with favorable disease-specific survival (DSS; S-PD-L1, P = .004; T-PD-1, P = .012), both limited to the squamous cell carcinoma histologic subgroup (S-PD-L1, P = .002; T-PD-1, P = .034). A combined low S-PD-L1 and T-PD-1 was associated with poor survival in all patients (DSS: hazard ratio [HR], 1.81; 95% confidence interval [CI], 1.37-2.40; P < .001) at both centers and for all pathologic stages. In multivariate analysis, S-PD-L1 and T-PD-1 were independent positive prognostic factors, and combined low scores remained an independent prognosticator for poor survival (DSS: HR, 1.72; 95% CI, 1.29-2.28; P < .001; disease-free survival, P = .001; overall survival, P = .005).

CONCLUSION

Our study identified S-PD-L1 and T-PD-1 as independent positive prognostic factors for NSCLC patients. Their combination added significant prognostic impact within each pathologic stage and hence are feasible to include in a TNM Immunoscore.

PD-L1 biomarker testing for non-small cell lung cancer: truth or fiction?

Research in cancer immunology is currently accelerating following a series of cancer immunotherapy breakthroughs during the last 5 years. Various monoclonal antibodies which block the interaction between checkpoint molecules PD-1 on immune cells and PD-L1 on cancer cells have been used to successfully treat non-small cell lung cancer (NSCLC), including some durable responses lasting years. Two drugs, nivolumab and pembrolizumab, are now FDA approved for use in certain patients who have failed or progressed on platinum-based or targeted therapies while agents targeting PD-L1, atezolizumab and durvalumab, are approaching the final stages of clinical testing. Despite impressive treatment outcomes in a subset of patients who receive these immune therapies, many patients with NSCLC fail to respond to anti-PD-1/PD-L1 and the identification of a biomarker to select these patients remains highly sought after. In this review, we discuss the recent clinical trial results of pembrolizumab, nivolumab, and atezolizumab for NSCLC, and the significance of companion diagnostic testing for tumor PD-L1 expression.

Immune checkpoint blockade as a potential therapeutic target in non-small cell lung cancer

INTRODUCTION

The recent emergence of immune checkpoint blockade therapy and the progression of immunobiology in cancer have spurred an increasing interest in the immunotherapy for advanced non-small cell lung cancer (NSCLC). Immune checkpoint inhibitors (ICIs), designed to directly target immune inhibitory molecules, have demonstrated efficacy in the treatment of patients with advanced NSCLC.

AREAS COVERED

In the present article, the authors summarize the mechanism, efficacy and safety of major ICIs for the treatment of advanced or metastatic NSCLC. Combinations of different ICIs or conventional therapy and/or targeted agents for NSCLC treatment in clinical trials are also updated. In addition, immune-related adverse events and the roles of inhibitory immune checkpoint molecules as potential biomarkers in the immune checkpoint blockade therapy for NSCLC are emphatically elucidated.

EXPERT OPINION

Immunotherapies targeting the immune checkpoint pathways have shown potential to generate durable responses and improve survival for NSCLC patients. Although the toxicity profile of this immunotherapy is manageable, immune-related adverse events and drug resistance may cause therapeutic failure. Therefore, a better understanding of the mechanisms underpinning its function and the potential side effects of ICIs, as well as the identification of predictive biomarkers for patient selection are essential.

Programmed cell death ligand-1 (PD-L1) expression by immunohistochemistry: could it be predictive and/or prognostic in non-small cell lung cancer?

Blockade of immune checkpoints has recently emerged as a novel therapeutic strategy in various tumors. In particular, monoclonal antibodies targeting programmed cell death 1 (PD-1) or its ligand (PD-L1) have been most studied in lung cancer, and PD-1 inhibitors are now established agents in the management of non-small cell lung cancer (NSCLC). The reports on high-profile clinical trials have shown the association of PD-L1 expression by immunohistochemistry (IHC) with higher overall response rates to the PD-1/PD-L1 axis blockade suggesting that PD-L1 expression may serve as a predictive marker. Unfortunately, however, each PD-1 or PD-L1 inhibitor is coupled with a specific PD-L1 antibody, IHC protocol and scoring system for the biomarker assessment, making the head-to-head comparison of the studies difficult. Similarly, multiple clinical series that correlated PD-L1 expression with clinicopathologic and/or molecular variables and/or survival have reported conflicting results. The discrepancy could be explained by the differences in ethnicity and/or histologic types included in the studies, but it appears to be attributed in part to the differences in PD-L1 IHC methods. Thus, orchestrated efforts to standardize the PD-L1 IHC are warranted to establish the IHC as a predictive and/or prognostic biomarker in NSCLC.