A systematic and genome-wide correlation meta-analysis of PD-L1 expression and targetable NSCLC driver genes

PD-L1 expression and its correlation with clinicopathological and molecular characteristics in Chinese patients with non-small cell lung cancer

Little is known about the relationship between programmed cell death-ligand 1 (PD-L1) expression and histologic and genetic features in real-world Chinese non-small cell lung cancer patients. From November 2017 to June 2019, tumor tissues were collected from 2674 non-small cell lung cancer patients. PD-L1 expression was detected with immunohistochemistry using the 22C3 and SP263 antibodies, and patients were stratified into subgroups based on a tumor proportion score of 1%, 1% to 49%, and ≥ 50%. Genetic alterations were profiled using targeted next-generation sequencing. In the total population, 50.5% had negative PD-L1 expression (tumor proportion score < 1%), 32.0% had low-positive expression (1%-49%), and 17.5% had high-positive expression (≥50%). The PD-L1 positive rate was 39.0% in squamous cell carcinomas and 53.6% in adenocarcinomas. PD-L1 expression was higher in squamous cell carcinomas (P < .001) and lower in adenocarcinomas (P < .001). Of the overall patient population, 11.2% had Kirsten rat sarcoma viral oncogene (KRAS) mutations, 44.9% had epidermal growth factor receptor (EGFR) mutations, 2.1% had BRAF V600E mutations, 0.3% had MET exon 14 skipping mutations, 5.4% had anaplastic lymphoma kinase translocations, and 0.9% had ROS proto-oncogene 1 translocations. Patients carrying ROS proto-oncogene 1 translocations (P = .006), KRAS (P < .001), and MET (P = .023) mutations had significantly elevated expression of PD-L1, while those harboring EGFR (P < .001) mutations had lower PD-L1 expression. In our study, PD-L1 expression was significantly higher in squamous cell carcinomas and lower in adenocarcinomas, and was positively associated with MET and KRAS mutations, as well as the wild-type EGFR gene state. Nonetheless, additional studies are needed to further validate those associations and determine the clinical significance for immune checkpoint inhibitors of these factors.

Prognostic value of KRAS mutations, TP53 mutations and PD-L1 expression among lung adenocarcinomas treated with immunotherapy

AIMS

The aim of this study was to investigate the association between oncogenic alterations and programmed cell death ligand 1 (PD-L1) expression in lung adenocarcinomas, as well as the prognostic value of KRAS and/or TP53 mutations in patients treated with immunotherapy.

METHODS

This study is a retrospective cohort study of 519 patients with lung adenocarcinomas analysed for mutations and PD-L1 expression. Data were collected from electronic pathology record system, next-generation sequencing system, and clinical databases. Association between mutations and PD-L1 expression was investigated, as well as survival statistics of the 65 patients treated with immunotherapy.

RESULTS

41% of the samples contained a KRAS mutation, predominantly together with mutations in TP53 (41%) or STK11 (10%). Higher expression of PD-L1 was seen among patients with KRAS mutations (p=0.002) and EGFR wild type (p=0.006). For patients treated with immunotherapy, there was no statistically significant difference for overall survival (OS) and progression-free survival (PFS) according to KRAS mutation status, TP53 mutation status or PD-L1 expression. The HR for concomitant mutations in TP53 and KRAS was 0.78 (95% CI 0.62 to 0.99) for OS and 0.43 (0.21 to 0.88) for PFS. Furthermore, concomitant TP53 and KRAS mutations predicted a better PFS (p=0.015) and OS (p=0.029) compared with no mutations or a single mutation in either TP53 or KRAS.

CONCLUSION

Mutations in TP53 together with KRAS may serve as a potential biomarker for survival benefits with immunotherapy.

Hope and Challenges: Immunotherapy in EGFR-Mutant NSCLC Patients

EGFR tyrosine kinase inhibitors (TKIs) are the preferred initial treatment for non-small cell lung cancer (NSCLC) patients harboring sensitive EGFR mutations. Sadly, remission is transient, and no approved effective treatment options are available for EGFR-TKI-advanced EGFR-mutant NSCLCs. Although immunotherapy with immune checkpoint inhibitors (ICIs) induces sustained cancer remission in a subset of NSCLCs, ICI therapy exhibits limited activity in most EGFR-mutant NSCLCs. Mechanistically, the strong oncogenic EGFR signaling in EGFR-mutant NSCLCs contributes to a non-inflamed tumor immune microenvironment (TIME), characterized by a limited number of CD8+ T cell infiltration, a high number of regulatory CD4+ T cells, and an increased number of inactivated infiltrated T cells. Additionally, EGFR-mutant NSCLC patients are generally non-smokers with low levels of PD-L1 expression and tumor mutation burden. Promisingly, a small population of EGFR-mutant NSCLCs still durably respond to ICI therapy. The hope of ICI therapy from pre-clinical studies and clinical trials is reviewed in EGFR-mutant NSCLCs. The challenges of application ICI therapy in EGFR-mutant NSCLCs are also reviewed.

Influence of PD-L1 expression on the efficacy of EGFR-TKIs in EGFR-mutant non-small cell lung cancer

BACKGROUND

Evidence on the influence of programmed death-ligand 1 (PD-L1) expression on the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in EGFR-mutant non-small cell lung cancer (NSCLC) patients is at variance.

METHODS

A single-center retrospective study was conducted to evaluate the influence of PD-L1 expression on the efficacy of EGFR-TKIs for NSCLC patients with EGFR mutation. Clinical information was retrieved from electronic medical records. The patients were divided into three subgroups according to PD-L1 expression level: PD-L1 < 1% (negative), PD-L1 1%-49% and PD-L1 ≥ 50%. The clinicopathological features, overall response rate (ORR), progression-free survival (PFS) and comutation information were collected and compared between the three subgroups.

RESULTS

A total of 117 patients were included. For PD-L1 < 1%, PD-L1 1%-49% and PD-L1 ≥ 50% group, there were 39 (33.3%), 51 (43.5%) and 27 (23.0%) patients respectively, and the ORR was 43.2%, 64.0%, and 51.9%, respectively (p = 0.162), and the median progression-free survival (mPFS) was 22.0 months (95% CI: 14.0-29.9 months), 15.4 months (95% CI: 8.9-21.8 months) and 13.0 months (95% CI: 10.6-15.3 months), respectively (log-rank, p = 0.01). The mPFS was negatively correlated with PD-L1 expression level (r = -0.264, p = 0.041) and PD-L1 expression was an independent risk factor for worse PFS of EGFR-TKIs in multivariate Cox regression. Patients with concurrent TP53 mutation had shorter PFS (p = 0.039) and the patients harboring both mutant TP53 and positive PD-L1 had the shortest PFS (p = 0.006).

CONCLUSIONS

The efficacy of EGFR-TKIs was influenced by the baseline PD-L1 expression. Higher PD-L1 expression was associated with shorter PFS. The combined indicators of TP53 and PD-L1 identified subgroups showing divergent benefits from EGFR-TKIs.

CRISPR/Cas9 Edited RAS & MEK Mutant Cells Acquire BRAF and MEK Inhibitor Resistance with MEK1 Q56P Restoring Sensitivity to MEK/BRAF Inhibitor Combo and KRAS G13D Gaining Sensitivity to Immunotherapy

Simple Summary

BRAF inhibitor drug resistance has been a long-time challenge in the treatment of melanoma with BRAF V600E mutation. This study employed the CRISPR/Cas9 technology to generate three isogenic A375 melanoma cell lines with point mutations of NRAS Q61K, KRAS G13D and MEK1 Q56P, respectively. They recapitulated the resistance to BRAF inhibitors in vitro as such mutations have been found in patients with acquired resistance to BRAF inhibitors during treatment. Hence, these novel isogenic cell lines become extremely useful tools for upcoming research in this field. Additionally, we determined that resistance in the NRAS and MEK isogenic lines is driven by constitutive MEK/ERK signaling, while the resistance in the KRAS isogenic line is driven by EGFR overexpression. The KRAS G13D isogenic line displays elevated PD-L1 expression suggesting the KRAS G13D mutation could be a potential indication for immunotherapy.

Abstract

BRAF V600E mutation drives uncontrolled cell growth in most melanomas. While BRAF V600E tumors are initially responsive to BRAF inhibitors, prolonged treatment results in inhibitor resistance and tumor regrowth. Clinical data have linked the NRAS Q61K, KRAS G13D and MEK1 Q56P mutations to the BRAF inhibitor resistance. However, development of novel therapeutics is hindered by the lack of relevant isogeneic cell models. We employed CRISPR/Cas9 genome engineering to introduce NRAS Q61K, KRAS G13D and MEK1 Q56P mutations into the A375 melanoma cell line with endogenously high expression of BRAF V600E. The resulting isogenic cell lines are resistant to BRAF inhibitors. The A375 MEK1 Q56P isogenic cells are additionally resistant to MEK inhibitors as single agent, but interestingly, these cells become sensitive to MEK/BRAF inhibitor combo. Our results suggest that resistance in the NRAS and MEK isogenic lines is driven by constitutive MEK/ERK signaling, while the resistance in the KRAS isogenic line is driven by EGFR overexpression. Interestingly, the KRAS G13D isogenic line displays elevated PD-L1 expression suggesting the KRAS G13D mutation could be a potential indication for immunotherapy. Overall, these three novel isogenic cell models with endogenous level RAS and MEK1 point mutations provide direct bio-functional evidence demonstrating that acquiring a drug-resistant gene drives tumor cell survival and may simultaneously introduce new indications for combo therapy or immunotherapy in the clinic.

Immunotherapy-based combination strategies for treatment of EGFR-TKI-resistant NSCLC

The rapid development of molecular targeted therapy brings hope to patients with advanced non-small-cell lung cancer (NSCLC). However, drug resistance inevitably occurs during treatment with EGFR-tyrosine kinase inhibitors (TKIs). Osimertinib, a third-generation EGFR-TKI, shows a favorable prognosis in T790M-positive NSCLC. Unfortunately, acquired resistance is still a challenge for both patients and clinicians. There is still no consensus on the optimal treatment. PD-1 and its ligand receptor 1 (PD-L1) inhibitors have yielded great progress, especially in patients with no actionable mutations. In this review, the authors take stock of the relationship between EGFR mutations and PD-L1 expression and summarize the important clinical studies on immunotherapy-inhibitor-based treatment in patients with EGFR-TKI-resistant NSCLC.

Melatonin Downregulates PD-L1 Expression and Modulates Tumor Immunity in KRAS-Mutant Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) patients harboring a KRAS mutation have unfavorable therapeutic outcomes with chemotherapies, and the mutation also renders tolerance to immunotherapies. There is an unmet need for a new strategy for overcoming immunosuppression in KRAS-mutant NSCLC. The recently discovered role of melatonin demonstrates a wide spectrum of anticancer impacts; however, the effect of melatonin on modulating tumor immunity is largely unknown. In the present study, melatonin treatment significantly reduced cell viability accompanied by inducing cell apoptosis in KRAS-mutant NSCLC cell lines including A549, H460, and LLC1 cells. Mechanistically, we found that lung cancer cells harboring the KRAS mutation exhibited a higher level of programmed death ligand 1 (PD-L1). However, treatment with melatonin substantially downregulated PD-L1 expressions in both the presence and absence of interferon (IFN)-γ stimulation. Moreover, KRAS-mutant lung cancer cells exhibited higher Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) levels, and PD-L1 expression was positively correlated with YAP and TAZ in lung cancer cells. Treatment with melatonin effectively suppressed YAP and TAZ, which was accompanied by downregulation of YAP/TAZ downstream gene expressions. The combination of melatonin and an inhibitor of YAP/TAZ robustly decreased YAP and PD-L1 expressions. Clinical analysis using public databases revealed that PD-L1 expression was positively correlated with YAP and TAZ in patients with lung cancer, and PD-L1 overexpression suggested poor survival probability. An animal study further revealed that administration of melatonin significantly inhibited tumor growth and modulated tumor immunity in a syngeneic mouse model. Together, our data revealed a novel antitumor mechanism of melatonin in modulating the immunosuppressive tumor microenvironment by suppressing the YAP/PD-L1 axis and suggest the therapeutic potential of melatonin for treating NSCLC.

PD-L1 Expression and Outcome in Patients with Metastatic Non-Small Cell Lung Cancer and EGFR Mutations Receiving EGFR-TKI as Frontline Treatment

Background

Epidermal growth factor receptor (EGFR) mutations are most common in Eastern Asia, and frequencies of 30–50% have been reported. EGFR-tyrosine kinase inhibitors (TKIs) are recommended as first-line therapeutic options for non-small cell lung cancer (NSCLC) with sensitizing EGFR mutations. Several immune checkpoint inhibitors have been successful in improving the outcomes of advanced lung cancer. The expression of programmed cell death-ligand 1 (PD-L1) on tumor cells plays an important role in predicting the efficacy of programmed cell death protein 1/PD-L1 inhibitors. The role of PD-L1 expression in tumors with EGFR mutation and its influence on clinical outcomes remain controversial.

Methods

Patients with newly diagnosed metastatic NSCLC with sensitizing EGFR mutations who received the standard treatment, ie, EGFR-TKIs for mutant adenocarcinoma as the first-line treatment, were enrolled in this retrospective study. EGFR mutations and PD-L1 expression levels were detected by Cobas RT-PCR and Dako 22C3 immunohistochemistry staining, respectively.

Results

From January 2011 to February 2019, 114 patients were enrolled. The average age was 62 years (range 34–92), and 45 (39.5%) patients were male. Among these patients, EGFR mutation analysis revealed exon 19 in-frame deletion in 55 (48.2%) patients, exon 21 L858R in 53 (46.5%) patients, and uncommon mutations in 6 (5.3%) patients. Among these patients with EGFR mutations, PD-L1 expression levels by tumor proportion score (TPS) were <1% in 54 (46.9%) patients, 1–49% in 50 (44.2%) patients, and ≥50% in 10 (8.8%) patients. All patients received EGFR-TKIs as first-line treatment, and in the Kaplan-Meier analysis, progression-free survival was not significantly different among groups with different PD-L1 expression status.

Conclusion

For patients with metastatic NSCLC and EGFR mutations, PD-L1 expression is not uncommon, but no significant influence on clinical outcomes was observed in patients receiving standard initial treatment.

A combination of PD‑1/PD‑L1 inhibitors: The prospect of overcoming the weakness of tumor immunotherapy (Review)

Programmed cell death protein-1 (PD-1)/programmed death protein ligand-1 (PD-L1) inhibitors for treatment of a various types of cancers have revolutionized cancer immunotherapy. However, PD-1/PD-L1 inhibitors are associated with a low response rate and are only effective on a small number of patients with cancer. Development of an anti-PD-1/PD-L1 sensitizer for improving response rate and effectiveness of immunotherapy is a challenge. The present study reviews the synergistic effects of PD-1/PD-L1 inhibitor with oncolytic virus, tumor vaccine, molecular targeted drugs, immunotherapy, chemotherapy, radiotherapy, intestinal flora and traditional Chinese medicine, to provide information for development of effective combination therapies.

Antitumour immunity regulated by aberrant ERBB family signalling

Aberrant signalling of ERBB family members plays an important role in tumorigenesis and in the escape from antitumour immunity in multiple malignancies. Molecular-targeted agents against these signalling pathways exhibit robust clinical efficacy, but patients inevitably experience acquired resistance to these molecular-targeted therapies. Although cancer immunotherapies, including immune checkpoint inhibitors (ICIs), have shown durable antitumour response in a subset of the treated patients in multiple cancer types, clinical efficacy is limited in cancers harbouring activating gene alterations of ERBB family members. In particular, ICI treatment of patients with non-small cell lung cancers with epidermal growth factor receptor (EGFR) alterations and breast cancers with HER2 alterations failed to show clinical benefits, suggesting that EGFR and HER2 signalling may have an essential role in inhibiting antitumour immune responses. Here, we discuss the mechanisms by which the signalling of ERBB family members affects not only autonomous cancer hallmarks, such as uncontrolled cell proliferation, but also antitumour immune responses in the tumour microenvironment and the potential application of immune-genome precision medicine into immunotherapy and molecular-targeted therapy focusing on the signalling of ERBB family members.

KRAS G12V mutation upregulates PD-L1 expression via TGF-β/EMT signaling pathway in human non-small-cell lung cancer

Although clinical data suggest remarkable promise for targeting programmed cell death protein-1 (PD-1) and ligand (PD-L1) signaling in non-small-cell lung cancer (NSCLC), it is still largely undetermined which subtype of patients will be responsive to checkpoint blockade. In the present study, we explored whether PD-L1 was regulated by mutant Kirsten rat sarcoma viral oncogene homolog (KRAS), which is frequently mutated in NSCLC and results in poor prognosis and low survival rates. We verified that PD-L1 levels were dramatically increased in KRAS mutant cell lines, particularly in NCI-H441 cells with KRAS G12V mutation. Overexpression of KRAS G12V remarkably elevated PD-L1 messenger RNA and protein levels, while suppression of KRAS G12V led to decreased PD-L1 levels in NCI-H441 cells. Consistently, higher levels of PD-L1 were observed in KRAS-mutated tissues as well as tumor tissues-derived CD4⁺ and CD8⁺ T cells using a tumor xenograft in B-NDG mice. Mechanically, both in vitro and in vivo assays found that KRAS G12V upregulated PD-L1 via regulating the progression of epithelial-to-mesenchymal transition (EMT). Moreover, pembrolizumab activated the antitumor activity and decreased tumor growth with KRAS G12V mutated NSCLC. This study demonstrates that KRAS G12V mutation could induce PD-L1 expression and promote immune escape via transforming growth factor-β/EMT signaling pathway in KRAS-mutant NSCLC, providing a potential therapeutic approach for NSCLC harboring KRAS mutations.

Programmed Cell Death Ligand 1 Expression in Resected Non-Small Cell Lung Cancer

BACKGROUND

Recently, anti-programmed cell death 1 (PD-1) and anti-programmed cell death ligand 1 (PD-L1) immunotherapies have yielded promising outcomes for patients with advanced non-small cell lung cancer (NSCLC) and led to great interest in applying these agents to treat resectable early-stage NSCLC. The objective of our study was to evaluate PD-L1 protein expression in resectable early-stage NSCLC specimens from a large Northern European cohort, examine the relationship to clinical characteristics, and demonstrate the prognostic role in resected NSCLC.

MATERIALS AND METHODS

A large cohort of 875 NSCLC tumors consisted of 337 patients from Sweden and 538 patients from Norway was studied. All the patients had undergone pulmonary resection, and most patients had had early-stage NSCLC. PD-L1 protein expression was assessed by immunohistochemistry using the Dako PD-L1 22C3 pharmDx kit. The tumor proportion score for PD-L1 protein expression was compared with comprehensive demographic and clinicopathologic data.

RESULTS

The overall prevalence of PD-L1 protein expression in the resectable NSCLC cohort was 9.5% at a tumor proportion score cutoff of ≥ 50%. Stage I NSCLC had lower PD-L1 expression compared with that of the other stages (P = .0012). PD-L1 expression correlated with wild-type EGFR gene expression (P = .0156) and mutated KRAS gene expression (P = .0004). No significant association was found between PD-L1 expression and mortality after multivariable adjustment for clinical characteristics, although the survival curves showed PD-L1 expression significantly correlated with a poor prognosis in the total NSCLC cohort and in the adenocarcinoma subgroup.

CONCLUSION

PD-L1 expression in the present large cohort of resectable NSCLC was relatively low compared with data from clinical trials of advanced NSCLC. PD-L1 expression correlated positively with tumor stage, wild-type EGFR, and KRAS mutation. PD-L1 expression was not found as an independent prognostic factor in the present study. These findings could be important in the future when evaluating the role of anti-PD-1/PD-L1 immunotherapy in the setting of neoadjuvant or adjuvant trials for early-stage resectable NSCLC.

Unique Genetic Characteristics and Clinical Prognosis of Female Patients with Lung Cancer Harboring RET Fusion Gene

Objectives: Since no report on the genetic characteristics of RET fusions in female patients with lung cancer is available, this study revealed the genetic and prognostic characteristics of female patients with lung cancer harboring RET fusion gene for the first time. Materials and Methods: The molecular portfolios of 1,652 patients with lung cancer who underwent targeted next-generation sequencing for screening candidate oncogenic drivers in their histological specimens from January 2016 to December 2018 were investigated in this study. Results: RET fusions were identified in 23 cases, 15 females [2.2% (15/685)] and eight males [0.9% (8/902)]. The most common fusions were KIF5B–RET in females [80% (12/15)] and CCDC6–RET in males [50% (4/8)], along with some rare RET fusions, including SLC39A8–RET, ITIH2–RET, FYCO1–RET and SLC25A36–RET in females, and MIR3924–RET, ZBTB41–RET and ITGA8–RET in males. Interestingly, the highly positive, moderate positive, and negative rates of PD–L1 staining in females were 33.3%, 8.3% and 58.3%, respectively; whereas those in males were 0%, 57.1% and 42.9%. Additionally, the progression-free survival (PFS) of stage IV patients was comparatively shorter in females, shown by the medians of 4.0 months in females and 6.0 months in males (P = 0.029). A 43-year-old female patient with metastatic lung adenocarcinoma, who harbored KIF5B–RET fusion and had highly positive PD–L1 staining, received nivolumab as second-line treatment. A partial response was achieved and remained for more than five months. Conclusion: Unique genetic characteristics and poor prognosis are found in female patients with lung cancer harboring RET fusion gene. Immune checkpoint inhibitors are a potential option for patients with high expression of PD–L1.

[Advances in the Influence of EGFR Mutation on the PD-L1 Expression in Non-small Cell Lung Cancer]

近年来，有关程序性死亡受体1（programmed death-1, PD-1）及其配体（programmed death-1 ligand, PD-L1）抑制剂的研究取得突破性进展，迅速改变着非小细胞肺癌（non-small cell lung cancer, NSCLC）的治疗模式。但表皮生长因子受体（epidermal growth factor receptor, EGFR）突变患者应用PD-1/PD-L1抑制剂的治疗效果并不理想。既往研究显示，肿瘤细胞PD-L1表达率与免疫抑制剂治疗效果存在相关性。但目前EGFR突变对PD-L1表达的影响并不能达成一致。我们将对相关研究进行总结，以期对基础研究或临床治疗有所帮助。

Role of the dynamic tumor microenvironment in controversies regarding immune checkpoint inhibitors for the treatment of non-small cell lung cancer (NSCLC) with EGFR mutations

Immunotherapy has been incorporated into the first- and second-line treatment strategies for non-small cell lung cancer (NSCLC), profoundly ushering in a new treatment landscape. However, both adaptive signaling and oncogenic (epidermal growth factor receptor (EGFR)-driven) signaling may induce PD-L1 upregulation in NSCLC. Nevertheless, the superiority of immune checkpoint inhibitors (ICIs) in advanced EGFR-mutant NSCLC is only moderate. ICIs appear to be well tolerated, but clinical activity for some advanced EGFR-mutant NSCLC patients has only been observed in a small proportion of trials. Hence, there are still several open questions about PD-L1 axis inhibitors in patients with NSCLC whose tumors harbor EGFR mutations, such as the effect of EGFR tyrosine kinase inhibitors (TKIs) or EGFR mutations in the tumor microenvironment (TME). Finding the answers to these questions requires ongoing trials and preclinical studies to identify the mechanisms explaining this possible increased susceptibility and to identify prognostic molecular and clinical markers that may predict benefits with PD-1 axis inhibition in this specific NSCLC subpopulation. The presence of multiple mechanisms, including dynamic immune TME profiles, changes in PD-L1 expression and low tumor mutational burdens, may explain the conflicting data regarding the correlation between PD-L1 axis inhibitors and EGFR mutation status. We conducted a review of this currently controversial topic in an attempt to aid in the decision-making process.

Programmed cell death ligand 1 expression in cytologic and surgical non-small cell lung carcinoma specimens from a single institution: Association with clinicopathologic features and molecular alterations

BACKGROUND

Programmed cell death ligand 1 (PD-L1) expression by the 22C3 pharmDx companion assay has been validated in surgical specimens to support pembrolizumab treatment decisions for patients with non-small cell lung carcinoma (NSCLC). The aims of this study were 1) to assess the adequacy of cytologic specimens for PD-L1 evaluation and 2) to explore correlations of PD-L1 expression with clinicopathologic and molecular features.

METHODS

The study cohort included 100 cytology specimens (fluid [n = 28] and fine-needle aspiration [n = 72]) and 165 surgical specimens (biopsy [n = 138] and resection [n = 27]). The PD-L1 immunohistochemistry 22C3 assay and staining assessment were performed according to the manufacturer's instructions. PD-L1 expression was correlated with patients' demographics, pathologic characteristics, and molecular alterations.

RESULTS

One hundred forty-two specimens (53.6%) were positive for PD-L1 expression (≥1%). No statistically significant difference in PD-L1 expression was identified between cytologic (56.0%) and surgical specimens (52.1%). Seventy-four of 190 tested cases (38.9%) had genetic alterations. PD-L1 positivity was significantly more prevalent in cases with genetic alterations than in cases without genetic alterations. Furthermore, both PD-L1 positivity and high PD-L1 expression (≥50%) had statistically significant associations with Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations. PD-L1 expression had no significant association with histologic phenotypes or other clinicopathologic features.

CONCLUSIONS

The data indicate that cytologic specimens are comparable to surgical specimens for PD-L1 evaluation. The association of PD-L1 expression with KRAS mutations may have clinical relevance in selecting patients with NSCLC for immunotherapy.

Programmed death ligand-1 expression in non-small cell lung cancer in a Western Australian population and correlation with clinicopathologic features

Immune checkpoint inhibition is an important therapeutic option in patients with non-small cell lung cancer. Programmed cell death ligand-1 (PD-L1) expression may serve as a predictive marker for anti-PD-1/PD-L1 therapies. The relationship between non-small cell lung cancer PD-L1 expression and clinicopathological characteristics remains unclear and there is no population level Australian data. We report the results of PD-L1 testing in patients with non-small cell lung cancer diagnosed at major Western Australian public hospitals served by a single state Pathology provider. We analyzed PD-L1 expression by immunohistochemistry in 241 non-small cell lung cancer specimens using the 22C3 clone on a Dako autostainer platform. Tumor cell PD-L1 expression was scored as Tumor Proportion Score and categorized using pre-specified subsets of  1%, 1-49% and  ≥  50% for correlation with clinicopathologic features. PD-L1 Tumor Proportion Score was  1% in 65 (27%) cases, 1-49% in 100 (41%) cases and  ≥  50% in 76 (32%) cases. PD-L1-positive rate was 92% in squamous cell carcinomas and 67% in adenocarcinomas. PD-L1 Tumor Proportion Score was higher in squamous cell carcinomas (p  =  0.004) and lower in adenocarcinomas (p  =  0.003). Of the 196 non-squamous carcinomas, 35% had rat sarcoma viral oncogene homolog (RAS) mutations, 13% had epidermal growth factor receptor (EGFR) mutations, 2% had anaplastic lymphoma kinase (ALK) translocations and 2% had ROS1 translocations. Tumor Proportion Score  ≥  50% was seen in 34% (23/68), 28% (7/25) and 25% (1/4) of RAS, EGFR mutant, and ALK translocated carcinomas, respectively. There was no significant correlation between PD-L1 expression and molecular or genetic abnormalities, or other parameters including age, gender, stage, and smoking status. In our patient cohort, PD-L1 Tumor Proportion Score was significantly higher in squamous cell carcinomas and lower in adenocarcinomas. The overall prevalence of Tumor Proportion Score  ≥  50% is consistent with that reported in clinical trials.

Programmed cell death protein-1/programmed death-ligand 1 blockade enhances the antitumor efficacy of adoptive cell therapy against non-small cell lung cancer

Background

Cytokine-induced killer (CIK) cells and natural killer (NK) cells are employed by two different approaches to adoptive cell immunotherapy for cancer. It has been reported that adoptive cell immunotherapy could prolong the overall survival (OS) of advanced cancer patients. The introduction of agents that induce immune checkpoint blockades has improved the efficacy of immune-mediated therapy for metastatic cancers. However, the effects of combining a checkpoint inhibitor with CIK cells or NK cells to target non-small cell lung cancer (NSCLC)remain unknown.

Methods

The present study investigated the effects of combining CIK cells with a programmed cell death protein-1 (PD-1) inhibitor (an anti-PD-1 monoclonal antibody). During the expansion cultivation, the addition of the PD-1 antibody promoted CIK-mediated cytotoxicity in H1975 lung adenocarcinoma cells. Co-cultivation of CIK cells with the PD-1 antibody for 6 days induced CD3⁺CD56⁺ T cell expansion, with increases in the levels of CD107a and interferon γ (IFN-γ).

Results

When NK cells were co-cultured with 5 µg/mL of an anti-programmed death-ligand 1 (PD-L1) mAb for 24 hours at an effector cell: target ratio of 10:1, it led to more potent cytotoxicity compared to other time points and concentrations. However, combining NK cells with the anti-PD-L1 mAb showed no significant advantages over treatment with NK cells alone.

Conclusions

Our results suggest that combining CIK cells with PD-1 blockade before transfusion might improve the efficiency of CIK therapy for NSCLC patients. This effect does not seem to occur for NK cell therapy.

The Clinicopathological and Molecular Associations of PD-L1 Expression in Non-small Cell Lung Cancer: Analysis of a Series of 10,005 Cases Tested with the 22C3 Assay

PD-L1 expression testing is mandatory prior to pembrolizumab prescription in non-small cell lung cancer. Our service offers PD-L1 testing using the PD-L1 IHC 22C3 pharmDx assay, in parallel with EGFR, ALK, ROS1 and (in some cases) KRAS testing. We correlate PD-L1 expression in 10,005 tumours with patient age and sex, with tumour histological subtypes, with the sampling modality and type of tissue, and with the presence of other molecular alterations. PD-L1 expression testing was performed using the aforementioned assay; tumour proportion scores (TPS) of 1 and 50% were taken as cut-offs for low and high positivity, respectively. EGFR testing was performed using the cobas® EGFR Mutation Test v2. ALK testing was performed using the VENTANA ALK (D5F3) CDx Assay. KRAS testing was performed using pyrosequencing. TPS <1% was seen in 44.4% of tumours, 1-49% in 25.0% and ≥ 50% in 30.6%. We identified no significant relationship with age. Female patients were slightly more likely to express PD-L1. Poorly-differentiated tumour histology and ALK translocation were significantly associated with PD-L1 expression. Rare EGFR mutations tended to be associated with PD-L1 expression. Pleural and nodal metastases were more likely to express PD-L1 than primary tumours, but biopsy and cytological specimens did not show different PD-L1 expression rates. Our data show that the means of acquiring a tumour sample (biopsy versus cytology) does not have a significant impact on PD-L1 expression. However, we found that certain metastatic sites were associated with significantly higher expression rates, which has substantial implications for selection of tissue for testing.

[Study Progression on Non-small Cell Lung Cancer with EGFR Mutation Treated by Immune Checkpoint Inhibitors]

In recent years, epidermal growth factor receptor tyrosine kinase inhibitors have been recommended by many guidelines as first-line drugs for advanced non-small cell lung cancer (NSCLC) with EGFR gene mutations and no resistance. However, with the prolongation of medication time, most appear acquired resistance. In recent years, breakthroughs in inhibitors of programmed death-1 (PD-1) and its ligand (PD1 ligand, PD-L1) have rapidly changed the therapeutic model of NSCLC. Recent studies have shown that the efficacy of immune checkpoint inhibitors in EGFR-mutant NSCLC patients is not satisfactory, which might be caused by low PD-L1 expression, inhibitory immune microenvironment and low tumor mutation load. This review will elaborate the immune microenvironment of NSCLC patients with EGFR mutation, the latest study progression of immune checkpoint inhibitors and its combined with TKI, expecting to bring new hopes for the treatment of EGFR-mutant NSCLC patients.
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Targeting the PD-1/PD-L1 axis for the treatment of non-small-cell lung cancer

Lung cancer is the leading cause of cancer-specific death among Canadians, with non-small-cell lung cancer (nsclc) being the most common histologic variant. Despite advances in the understanding of the molecular biology of nsclc, the survival rate for this malignancy is still poor. It is now understood that, to evade detection and immune clearance, nsclc tumours overexpress the immunosuppressive checkpoint protein programmed death ligand 1 (PD-L1). Inhibiting the PD-1/PD-L1 axis with monoclonal antibodies has significantly changed the treatment landscape in nsclc during the last 5 years. Despite evidence of clinical response in some patients, only approximately 20% of patients obtain any durable benefit, and many of the patients who do respond ultimately relapse with drug-resistant disease. The identification of patients who are most likely to benefit from such therapy is therefore important. In the present review, we cover the basics of the PD-1/PD-L1 axis and its clinical significance in nsclc, biomarkers that are predictive of treatment response, relevant clinical trials of PD-1/PD-L1 blockade completed to date, and proposed mechanisms of acquired therapeutic resistance.

PD-L1 expression and its effect on clinical outcomes of EGFR-mutant NSCLC patients treated with EGFR-TKIs

Objective:

Epidermal growth factor receptor (EGFR) activation was reported to upregulate programmed death-ligand 1 (PD-L1) expression in lung cancer cells and subsequently contribute to immune escape, indicating its critical role in EGFR-driven lung tumors. This study characterized PD-L1 expression in patients with surgically resected EGFR-mutant non-small cell lung cancer (NSCLC). The effect of PD-L1 expression on clinical outcomes was also investigated in advanced EGFR-mutant NSCLC treated with EGFR-tyrosine kinase inhibitors (TKIs).

Methods:

In total, 73 patients with surgically resected NSCLC and EGFR mutations were identified. PD-L1 expression and CD8+ tumor-infiltrating lymphocyte (TIL) density were assessed by immunohistochemistry. A literature review of publications that assessed the predictive and prognostic value of PD-L1 expression in advanced EGFR-mutant NSCLC patients treated with EGFR-TKIs was performed.

Results:

Nineteen (26.0%) patients were positive for PD-L1 expression, which was significantly associated with concomitant KRAS mutation (P = 0.020) and marginally associated with higher CD8+ TILs density (P = 0.056). Positive PD-L1 expression was associated with markedly inferior overall survival (OS) in multivariate analysis (P = 0.032). The combination of PD-L1 and CD8+ TILs expression could be used to stratify the population into three groups with distinct prognoses. A meta-analysis of six publications showed that positive PD-L1 expression was not associated with OS [hazard ratio (HR) = 0.90; 95% confidence interval (CI), 0.42–1.38] or progression-free survival (HR = 1.03; 95 CI, 0.73–1.33) in advanced EGFR-mutant NSCLC patients receiving EGFR-TKIs.

Conclusions:

PD-L1 expression tended to correlate with CD8+ TIL expression, concomitant KRAS mutation, and poor survival in surgically resected EGFR-mutant NSCLC. PD-L1 expression was neither the predictive nor the prognostic factor in advanced EGFR-mutant NSCLC patients treated with EGFR-TKIs.