Immune Checkpoint Blockade for Advanced NSCLC: A New Landscape for Elderly Patients

Lung Microbiome as a Treatable Trait in Chronic Respiratory Disorders

Once thought to be a sterile environment, it is now established that lungs are populated by various microorganisms that participate in maintaining lung function and play an important role in shaping lung immune surveillance. Although our comprehension of the molecular and metabolic interactions between microbes and lung cells is still in its infancy, any event causing a persistent qualitative or quantitative variation in the composition of lung microbiome, termed "dysbiosis", has been virtually associated with many respiratory diseases. A deep understanding of the composition and function of the "healthy" lung microbiota and how dysbiosis can cause or participate in disease progression will be pivotal in finding specific therapies aimed at preventing diseases and restoring lung function. Here, we review lung microbiome dysbiosis in different lung pathologies and the mechanisms by which these bacteria can cause or contribute to the severity of the disease. Furthermore, we describe how different respiratory disorders can be caused by the same pathogen, and that the real pathogenetic mechanism is not only dependent by the presence and amount of the main pathogen but can be shaped by the interaction it can build with other bacteria, fungi, and viruses present in the lung. Understanding the nature of this bacteria crosstalk could further our understanding of each respiratory disease leading to the development of new therapeutic strategies.

Current challenges and perspectives in lung cancer care during COVID-19 waves

PURPOSE OF REVIEW

In the era of the SARS-Cov2 pandemic, the multidisciplinary care of patients with lung cancer is the main challenge for clinicians. The depiction of complex networking between SARS-CoV2 and cancer cells is crucial to understanding the downstream signalling pathways leading to more severe clinical behaviour of COVID-19 among lung cancer patients.

RECENT FINDINGS

The immunosuppressive status caused by both blunted immune response and active anticancer treatments (e.g. radiotherapy, chemotherapy) affects also the response to vaccines. Furthermore, the COVID-19 pandemic has significantly influenced early detection, therapeutic management, and clinical research for patients with lung cancer.

SUMMARY

SARS-CoV-2 infection does undoubtedly represent a challenge for care of patients with lung cancer. Since symptoms of infection may overlap with underlying condition, diagnosis must be reached and treatment should start as soon as possible. Although any cancer treatment should be procrastinated as long as infection is not cured, every choice must be pondered on individual basis, according to clinical conditions. Underdiagnosis should be avoided, and both surgical and medical treatment must be tailored to each patient. Therapeutic scenario standardization represents a major challenge for clinicians and researchers.

Triptolide reduces PD-L1 through the EGFR and IFN-γ/IRF1 dual signaling pathways

As the principal ligand of programmed death 1 (PD-1), PD-L1 can induce the exhaustion of effector T cells and the escape of cancer cells through interacting with PD-1 in many solid malignancies. Therefore, targeting the PD-1/PD-L1 axis has become an attractive strategy in cancer immunotherapy. However, at present, no small-molecule agents targeting PD1/PD-L1 pathways have been successfully used in clinical applications. Here, we first found that the natural product Triptolide could significantly reduce the PD-L1 expression on the surface of NSCLC cells. This down-regulation is related to the activity of EGFR signaling pathway. Moreover, the reduction of PD-L1 caused by Triptolide could be substantially rescued by IFN-γ. Furthermore, our findings suggest that Triptolide significantly inhibits the activity of the IFN-γ-JAK-STAT-IRF1 signaling axis, as evidenced by the noticeable reduction in both basal and phosphorylated levels of STAT3. Thus, in NSCLC cells, Triptolide reduces PD-L1 expression both through the EGFR and IFN-γ/JAK1/JAK2/STAT1/STAT3/IRF1 signaling pathways. The results provide new insights into the application of Triptolide in the immune checkpoints treatment of NSCLCs.

Targeting YAP/TAZ in Combination with PD-L1 Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer (NSCLC)

The survival of non-small cell lung cancer (NSCLC) patients has improved in the last decade as a result of introducing new therapeutics, such as immune checkpoint inhibitors, in the clinic. Still, some NSCLC patients do not benefit from these therapies due to intrinsic resistance or the development of acquired resistance and their malignant disease progresses. Further research on the molecular underpinnings of NSCLC pathobiology is required in order to discover clinically relevant molecular targets that regulate tumor immunity and to develop reasonable therapeutic combinations that will promote the efficacy of immune checkpoint inhibitors. Yes-associated Protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), the final effectors of the Hippo signaling transduction pathway, are emerging as key players in NSCLC development and progression. Herein, we overview studies that have investigated the oncogenic role of YAP/TAZ in NSCLC, focusing on immune evasion, and highlight the therapeutic potential of combining YAP/TAZ inhibitory agents with immune checkpoint inhibitors for the management of NSCLC patients.

Complete response to pembrolizumab as a single agent in a patient with stage III NSCLC with high PD-L1 expression: a case report

Non-small cell lung cancer (NSCLC) accounts for 75-80% of all lung cancer cases. Stage III NSCLC represents a highly heterogenous stage characterized by different disease presentations and a wide range of treatment options. For patients with good performance status and unresectable-stage III NSCLC with programmed death-ligands 1 (PD-L1) tumor proportion score (TPS) ≥1%, durvalumab consolidation immunotherapy after a platinum-based chemo-radiotherapy is strongly recommended. However, age, poor performance status, underlying comorbidities may represent contraindications for chemotherapy to be used in a subgroup of patients. Herein, we report a case of an 80-year-old male affected by a stage IIIB lung adenocarcinoma with overexpression of PD-L1 (TPS 90%) treated with pembrolizumab, an immune checkpoint inhibitor targeting PD-1/PD-L1 pathways, which shows a complete resolution of lung lesion after four cycles of treatment. Although randomized controlled trials are required, this case report may suggest the potential role of pembrolizumab for chemotherapy unsuitable patients with overexpressing PD-L1 unresectable-stage III NSCLC.

Immune senescence in non-small cell lung cancer management: therapeutic relevance, biomarkers, and mitigating approaches

INTRODUCTION

Lung cancer and mainly non-small cell lung cancer (NSCLC) still remain a prevalent malignancy worldwide despite sustained screening approaches. Furthermore, a significant proportion of the cases are diagnosed at advanced stages when conservative therapy is often unsuccessful. Cell senescence is an endogenous antitumor weapon but when it is upregulated exerts opposite activities favoring tumor metastasizing and poor response to therapy. However, little is known about this dangerous relationship between cell senescence and NSCLC outcome or on potential approaches to mitigate its unfavorable consequences.

AREAS COVERED

We discuss cell senescence focusing on immune senescence, its cell and humoral effectors (namely immune senescence associated secretory phenotype-iSASP), its impact on NSCLC outcome, and its biomarkers. Senotherapeutics as mitigating approaches are also considered based on the availability of experimental data pertinent to NSCLC.

EXPERT OPINION

Characterization of NSCLC subsets in which immune senescence is a risk factor for poor prognosis and poor therapeutic response might be very helpful in supporting the addition of senotherapeutics to conventional cancer therapy. This approach has the potential to improve disease outcome but more studies in this area are necessary.

Alectinib rescue therapy in advanced ALK rearranged lung adenocarcinoma: a case report

Alectinib is a highly selective tyrosine kinase inhibitor of anaplastic lymphoma kinase (ALK) that is approved as first-line treatment in adult patients with ALK-positive non-small cell lung cancer (NSCLC) and as second-line in patients previously treated with crizotinib, and has been shown in the literature to significantly prolong progression-free survival compared to chemotherapy in patients with advanced non-small cell lung cancer. The authors describe a clinical case of a 24-year-old woman with malignant massive pleural effusion caused by ALK rearranged pulmonary adenocarcinoma with pleural and pericardial metastasis, in which, despite a dramatic clinical debut, the correct and timely management of the diagnostic and therapeutic path allowed for extraordinary therapeutic success.

Pembrolizumab monotherapy for untreated PD-L1-Positive non-small cell lung cancer in the elderly or those with poor performance status: A prospective observational study

Objectives

We investigated the efficacy and safety of pembrolizumab monotherapy as first-line treatment for poor Eastern Cooperative Oncology Group performance status (PS) and elderly patients with programmed cell death-ligand 1 (PD-L1)-positive advanced non-small cell lung cancer (NSCLC). We also investigated clinical prognostic factors for the efficacy of pembrolizumab monotherapy, based on patient characteristics.

Materials and methods

In this prospective observational study, PS-2 and elderly NSCLC patients with PD-L1 tumor proportion score (TPS) ≥1% who received first-line pembrolizumab monotherapy, from October 2019 to March 2021, at 10 institutions in Japan were enrolled. Patients judged eligible by their physicians for combined chemotherapy and PD-1/PD-L1 inhibitors as first-line treatment were excluded. Clinicopathological characteristics and adverse events were investigated for correlation with clinical outcomes.

Results

Forty patients were enrolled in the study. The median progression-free survival (PFS) of patients with PS 2 and those aged ≥ 75 years were 4.4 (95% confidence interval [CI]: 0.9–14.4) months and 5.3 (95% CI 2.9–9.4) months, respectively. The median overall survival (OS) of patients with PS 2 and those aged ≥ 75 years were 11.6 (95% CI: 1.4–not evaluable [NE]) months and 11.6 (95% CI 7.4–18.1) months, respectively. Immune-related adverse events (irAEs) were observed in 19 patients; 6 patients had severe irAEs of Common Terminology Criteria for Adverse Events (CTCAE) Grade 3 or higher. Patients who achieved stable disease or better, had a statistically significant increase in PFS (p < 0.001) and OS (p < 0.001). In the multivariate analysis, the acquisition of disease control with pembrolizumab monotherapy was an independent prognostic factor for PFS and OS.

Conclusion

Pembrolizumab monotherapy was relatively effective and tolerable as a first-line treatment for patients with PD-L1-positive advanced NSCLC who had poor PS or were elderly. Our results suggest that disease control might be an independent prognostic factor for PFS and OS in this population. (UMIN000044052 https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000050176)

Frailty in Patients With Lung Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Previous studies regarding the prevalence of frailty in patients with lung cancer and mortality in frail patients with lung cancer are inconsistent and require clarification.

RESEARCH QUESTION

What is the prevalence and impact of frailty in patients with lung cancer?

STUDY DESIGN AND METHODS

This systematic review and meta-analysis used a combination of free-text terms and medical subject headings terms, according to the database requirements in MEDLINE/PubMed, Scopus, and Cochrane Library from inception until November 15, 2020.

RESULTS

A total of 2,571 articles were identified, and 16 articles involving 4,183 patients were included for study. The prevalence of frailty in lung cancer was 45% (95% CI, 28-61; I² = 99.5%; P < .0001). In patients with lung cancer, frailty was associated with an increased hazard ratio for mortality (hazard ratio, 3.01; 95% CI, 1.77-5.10; P < .001).

INTERPRETATION

The prevalence of frailty in lung cancer is 45%, which has a significant negative impact on survival of patients with lung cancer. These results highlight the importance of measuring frailty, which provides important prognostic information, and may provide opportunities for interventions to improve outcomes in patients with lung cancer.

Role of Senescence and Aging in SARS-CoV-2 Infection and COVID-19 Disease

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in a global pandemic associated with substantial morbidity and mortality worldwide, with particular risk for severe disease and mortality in the elderly population. SARS-CoV-2 infection is driven by a pathological hyperinflammatory response which results in a dysregulated immune response. Current advancements in aging research indicates that aging pathways have fundamental roles in dictating healthspan in addition to lifespan. Our review discusses the aging immune system and highlights that senescence and aging together, play a central role in COVID-19 pathogenesis. In our review, we primarily focus on the immune system response to SARS-CoV-2 infection, the interconnection between severe COVID-19, immunosenescence, aging, vaccination, and the emerging problem of Long-COVID. We hope to highlight the importance of identifying specific senescent endotypes (or "sendotypes"), which can used as determinants of COVID-19 severity and mortality. Indeed, identified sendotypes could be therapeutically exploited for therapeutic intervention. We highlight that senolytics, which eliminate senescent cells, can target aging-associated pathways and therefore are proving attractive as potential therapeutic options to alleviate symptoms, prevent severe infection, and reduce mortality burden in COVID-19 and thus ultimately enhance healthspan.

Immune checkpoint inhibitors: a new landscape for extensive stage small cell lung cancer treatment

Introduction: Landscape of Extensive Stage (ES)-SCLC treatment has been unchanged over the years. Chemotherapy, mostly based on cisplatin and etoposide, remained the standard-of-care for patients with ES-SCLC for almost 40 years. Recently, immune check points inhibitors have emerged marking a turning point for ES-SCLC treatmentAreas covered: Aim of the paper is to discuss ICIs impact on ES-SCLC treatment algorithms, review current clinical trials, and explore future perspectives.Expert opinion: A growing body of evidence supports ICI-containing regimens as a new mainstay of ES-SCLC treatment. Whether subgroups of SCLC patients may have greater survival benefits from ICIs treatment needs to be better defined. Understanding the impact of tumor microenvironment and identifying reliable predictive and/or prognostic biomarkers will be fundamental to move toward a personalized treatment approach leading to improved survival.

Hydrogen therapy can be used to control tumor progression and alleviate the adverse events of medications in patients with advanced non-small cell lung cancer

Chemotherapy, targeted therapy, and immunotherapy are used against advanced non-small cell lung cancer. A clinically efficacious method for relieving the adverse events associated of such therapies is lacking. Fifty-eight adult patients were enrolled in our trial to relieve pulmonary symptoms or the adverse events of drugs. Twenty patients who refused drug treatment were assigned equally and randomly to a hydrogen (H₂)-only group and a control group. According to the results of tumor-gene mutations and drug-sensitivity tests, 10, 18, and 10 patients were enrolled into chemotherapy, targeted therapy, and immunotherapy groups in which these therapies were combined with H₂-therapy, respectively. Patients underwent H₂ inhalation for 4–5 hours per day for 5 months or stopped when cancer recurrence. Before study initiation, the demographics (except for tumor-mutation genes) and pulmonary symptoms (except for moderate cough) of the five groups showed no significant difference. During the first 5 months of treatment, the prevalence of symptoms of the control group increased gradually, whereas that of the four treatment groups decreased gradually. After 16 months of follow-up, progression-free survival of the control group was lower than that of the H₂-only group, and significantly lower than that of H₂ + chemotherapy, H₂ + targeted therapy, and H₂ + immunotherapy groups. In the combined-therapy groups, most drug-associated adverse events decreased gradually or even disappeared. H₂ inhalation was first discovered in the clinic that can be used to control tumor progression and alleviate the adverse events of medications for patients with advanced non-small cell lung cancer. This study was approved by the Ethics Committee of Fuda Cancer Hospital of Jinan University on December 7, 2018 (approval No. Fuda20181207), and was registered at ClinicalTrials.gov (Identifier: NCT03818347) on January 28, 2019.

Immunotherapy Management in Special Cancer Patient Populations

Patients with autoimmune disorders, multiple comorbidities, poor performance status, advanced age, and infection with SARS-CoV-2 (COVID-19) each represent unique subgroups of patients with cancer to whom little is known of the effects, benefits, and complications of checkpoint inhibitor (CPI) therapy. Although prospective trials are lacking in these populations, retrospective data and cohort series suggest that these patients can safely receive and benefit from CPI therapy. Here, we review the relevant data available and offer clinical recommendations in managing these complex patients with CPI therapy, where otherwise indicated.

Food, Nutrition, Physical Activity and Microbiota: Which Impact on Lung Cancer?

Lung cancer still represents the leading cause of cancer-related death, globally. Likewise, malnutrition and inactivity represent a major risk for loss of functional pulmonary capacities influencing overall lung cancer severity. Therefore, the adhesion to an appropriate health lifestyle is crucial in the management of lung cancer patients despite the subtype of cancer. This review aims to summarize the available knowledge about dietary approaches as well as physical activity as the major factors that decrease the risk towards lung cancer, and improve the response to therapies. We discuss the most significant dietary schemes positively associated to body composition and prognosis of lung cancer and the main molecular processes regulated by specific diet schemes, functional foods and physical activity, i.e., inflammation and oxidative stress. Finally, we report evidence demonstrating that dysbiosis of lung and/or gut microbiome, as well as their interconnection (the gut–lung axis), are strictly related to dietary patterns and regular physical activity playing a key role in lung cancer formation and progression, opening to the avenue of modulating the microbiome as coadjuvant therapy. Altogether, the evidence reported in this review highlights the necessity to consider non-pharmacological interventions (nutrition and physical activity) as effective adjunctive strategies in the management of lung cancer.

Adverse Effects of Anti-PD-1/PD-L1 Therapy in Non-small Cell Lung Cancer

Currently, immunotherapy has shown great efficacy in clinical trials, and monoclonal antibodies directed against immune checkpoint PD-1/PD-L1 have shown encouraging results in first-line or second-line treatment of non-small cell lung cancer patients. Meanwhile, anti-PD-1/PD-L1 immune checkpoint drugs combined with other treatments, such as chemotherapy, targeted therapy as well as anti-CTLA-4 checkpoint therapy, are considered an attractive treatment with higher efficacy. However, toxicity associated with PD-1/PD-L1 blockade is worth attention. Understanding the adverse effects caused by anti-PD-1/PD-L1 immunosuppressive agents is vital to guide the clinical rational use of drug. In this review, we summarized the adverse effects that occurred during the clinical use of anti-PD-1/PD-L1 inhibitors in the treatment of non-small cell lung cancer and discussed how to effectively manage and respond to these adverse reactions.

COVID-19 and the elderly: insights into pathogenesis and clinical decision-making

The elderly may represent a specific cluster of high-risk patients for developing COVID-19 with rapidly progressive clinical deterioration. Indeed, in older individuals, immunosenescence and comorbid disorders are more likely to promote viral-induced cytokine storm resulting in life-threatening respiratory failure and multisystemic involvement. Early diagnosis and individualized therapeutic management should be developed for elderly subjects based on personal medical history and polypharmacotherapy. Our review examines the pathogenesis and clinical implications of ageing in COVID-19 patients; finally, we discuss the evidence and controversies in the management in the long-stay residential care homes and aspects of end-of-life care for elderly patients with COVID-19.

Intratumoral Versus Circulating Lymphoid Cells as Predictive Biomarkers in Lung Cancer Patients Treated with Immune Checkpoint Inhibitors: Is the Easiest Path the Best One?

The molecular and cell determinants that modulate immune checkpoint (ICI) efficacy in lung cancer are still not well understood. However, there is a necessity to select those patients that will most benefit from these new treatments. Recent studies suggest the presence and/or the relative balance of specific lymphoid cells in the tumor microenvironment (TEM) including the T cell (activated, memory, and regulatory) and NK cell (CD56dim/bright) subsets, and correlate with a better response to ICI. The analyses of these cell subsets in peripheral blood, as a more accessible and homogeneous sample, might facilitate clinical decisions concerning fast prediction of ICI efficacy. Despite recent studies suggesting that lymphoid circulating cells might correlate with ICI efficacy and toxicity, more analyses and investigation are required to confirm if circulating lymphoid cells are a relevant picture of the lung TME and could be instrumental as ICI response biomarkers. This short review is aimed to discuss the recent advances in this fast-growing field.

The Crosstalk between Src and Hippo/YAP Signaling Pathways in Non-Small Cell Lung Cancer (NSCLC)

The advancement of new therapies, including targeted therapies and immunotherapies, has improved the survival of non-small-cell lung cancer (NSCLC) patients in the last decade. Some NSCLC patients still do not benefit from therapies or encounter progressive disease during the course of treatment because they have intrinsic resistance, acquired resistance, or lack a targetable driver mutation. More investigations on the molecular biology of NSCLC are needed to find useful biomarkers for current therapies and to develop novel therapeutic strategies. Src is a non-receptor tyrosine kinase protein that interacts with cell surface growth factor receptors and the intracellular signaling pathway to maintain cell survival tumorigenesis in NSCLC. The Yes-associated protein (YAP) is one of the main effectors of the Hippo pathway and has been identified as a promoter of drug resistance, cancer progression, and metastasis in NSCLC. Here, we review studies that have investigated the activation of YAP as mediated by Src kinases and demonstrate that Src regulates YAP through three main mechanisms: (1) direct phosphorylation; (2) the activation of pathways repressing Hippo kinases; and (3) Hippo-independent mechanisms. Further work should focus on the efficacy of Src inhibitors in inhibiting YAP activity in NSCLC. In addition, future efforts toward developing potentially reasonable combinations of therapy targeting the Src–YAP axis using other therapies, including targeted therapies and/or immunotherapies, are warranted.

Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration for PD-L1 Testing in Non-small Cell Lung Cancer

BACKGROUND

Programmed death-ligand 1 (PD-L1) expression on cancer cells is a clinically important biomarker to select patients with non-small cell lung cancer (NSCLC) for treatment with programmed death-1/PD-L1 inhibitors. Clinical trials of immunotherapy in patients with NSCLC have required histologic evidence for PD-L1 testing; in clinical practice, cytologic samples commonly are acquired in patients with advanced disease.

RESEARCH QUESTION

This study aims to investigate whether endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples are adequate for PD-L1 testing in NSCLC.

STUDY DESIGN AND METHODS

This study investigates the sampling adequacy of EBUS-TBNA for PD-L1 testing when compared with other methods. Furthermore, the relationship between clinicopathologic characteristics and PD-L1 expression in the study population have been examined. Five hundred seventy-seven NSCLC specimens were analyzed from consecutive patients with NSCLC across six centers in the United Kingdom and one center in the United States between January 2015 and December 2016.

RESULTS

In the EBUS-TBNA group (189 specimens), the overall percentage of patients with successful PD-L1 testing was 94.7%. There was no significant difference in sampling adequacy with other methods of tissue acquisition. Older patients had higher failure rates of PD-L1 testing (OR, 1.06; P = .008). In multivariate analysis, advanced N-stage (P = .048) and presence of brain metastasis (P < .001) were associated with high PD-L1 expression.

INTERPRETATION

This large multicenter study shows that EBUS-TBNA provides samples adequate for PD-L1 testing and that advanced N stage and the presence of brain metastasis are associated with high PD-L1 expression.

Therapeutic potentials of curcumin in the treatment of non-small-cell lung carcinoma

Non-small-cell lung carcinoma (NSCLC) is one of the most lethal malignancies that include more than 80% of lung cancer cases worldwide. During the past decades, plants and plant-derived products have attracted great interest in the treatment of various human diseases. Curcumin, the turmeric isolated natural phenolic compound, has shown a promising chemo-preventive and anticancer agent. Numerous studies have shown that curcumin delays the initiation and progression of NSCLC by affecting a wide range of molecular targets and cell signalling pathways including NF-kB, Akt, MAPKS, BCL-2, ROS and microRNAs (miRNAs). However, the poor oral bioavailability and low chemical stability of curcumin remain as major challenges in the utilisation of this compound as a therapeutic agent. Different analogs of curcumin and new delivery systems (e.g., micelles, nanoparticles and liposomes) provided promising solutions to overcome these obstacles and improve curcumin pharmacokinetic profile. The present review focuses on current reported studies about anti-NSCLC effects of curcumin. NSCLC involved miRNAs whose expression is regulated by curcumin has also been discussed. Furthermore, recent researches on the use of curcumin analogs and delivery systems to enhance the curcumin benefits in NSCLC are also described.

Prognostic Factors and Biomarkers of Responses to Immune Checkpoint Inhibitors in Lung Cancer

Manipulation of the immune response is a game changer in lung cancer treatment, revolutionizing management. PD1 and CTLA4 are dynamically expressed on different T cell subsets that can either disrupt or sustain tumor growth. Monoclonal antibodies (MoAbs) against PD1/PDL1 and CTLA4 have shown that inhibitory signals can be impaired, blocking T cell activation and function. MoAbs, used as both single-agents or in combination with standard therapy for the treatment of advanced non-small cell lung cancer (NSCLC), have exhibited advantages in terms of overall survival and response rate; nivolumab, pembrolizumab, atezolizumab and more recently, durvalumab, have already been approved for lung cancer treatment and more compounds are in the pipeline. A better understanding of signaling elicited by these antibodies on T cell subsets, as well as identification of biological determinants of sensitivity, resistance and correlates of efficacy, will help to define the mechanisms of antitumor responses. In addition, the relevance of T regulatory cells (Treg) involved in immune responses in cancer is attracting increasing interest. A major challenge for future research is to understand why a durable response to immune checkpoint inhibitors (ICIs) occurs only in subsets of patients and the mechanisms of resistance after an initial response. This review will explore current understanding and future direction of research on ICI treatment in lung cancer and the impact of tumor immune microenvironment n influencing clinical responses.

Epidermal Growth Factor Receptor (EGFR) Pathway, Yes-Associated Protein (YAP) and the Regulation of Programmed Death-Ligand 1 (PD-L1) in Non-Small Cell Lung Cancer (NSCLC)

The epidermal growth factor receptor (EGFR) pathway is a well-studied oncogenic pathway in human non-small cell lung cancer (NSCLC). A subset of advanced NSCLC patients (15–55%) have EGFR-driven mutations and benefit from treatment with EGFR-tyrosine kinase inhibitors (TKIs). Immune checkpoint inhibitors (ICIs) targeting the PD-1/PDL-1 axis are a new anti-cancer therapy for metastatic NSCLC. The anti-PD-1/PDL-1 ICIs showed promising efficacy (~30% response rate) and improved the survival of patients with metastatic NSCLC, but the role of anti-PD-1/PDL-1 ICIs for EGFR mutant NSCLC is not clear. YAP (yes-associated protein) is the main mediator of the Hippo pathway and has been identified as promoting cancer progression, drug resistance, and metastasis in NSCLC. Here, we review recent studies that examined the correlation between the EGFR, YAP pathways, and PD-L1 and demonstrate the mechanism by which EGFR and YAP regulate PD-L1 expression in human NSCLC. About 50% of EGFR mutant NSCLC patients acquire resistance to EGFR-TKIs without known targetable secondary mutations. Targeting YAP therapy is suggested as a potential treatment for NSCLC with acquired resistance to EGFR-TKIs. Future work should focus on the efficacy of YAP inhibitors in combination with immune checkpoint PD-L1/PD-1 blockade in EGFR mutant NSCLC without targetable resistant mutations.