Clinical and Molecular Predictors of PD-L1 Expression in Non-Small-Cell Lung Cancer: Systematic Review and Meta-analysis

Consistency Analysis of Programmed Death Ligand 1 Expression in Non-Small Cell Lung Cancer Between Pleural Effusion and Matched Primary Lung Cancer Tissues by Immunohistochemical Double Staining

In clinical practice, programmed death ligand 1 (PD-L1) detection is prone to nonspecific staining due to the complex cellular composition of pleural effusion smears. In this study, diaminobenzidine (DAB) and 3-amino-9-ethylcarbazole (AEC) immunohistochemistry double staining was performed to investigate PD-L1 expression in tumor cells from malignant pleural effusion (MPE). MPE was considered as a metastasis in non-small cell lung cancer patients; thus, the heterogeneity between metastatic and primary lung cancer was revealed as well. Ninety paired specimens of MPE cell blocks and matched primary lung cancer tissues from non-small cell lung cancer patients were subjected to PD-L1 and thyroid transcription factor-1(TTF-1)/p63 immunohistochemistry double staining. Two experienced pathologists independently evaluated PD-L1 expression using 3 cutoffs (1%, 10%, and 50%). PD-L1 expression in MPE was strongly correlated with that in matched primary lung cancer tissues (R = 0.813; P < .001). Using a 4-tier scale (cutoffs: 1%, 10%, and 50%), the concordance was 71.1% (Cohen's κ = .534). Using a 2-tier scale, the concordance was 75.6% (1%, Cohen's κ = 0.53), 78.9% (10%, Cohen's κ = 0.574), and 95.6% (50%, Cohen's κ = 0.754). The rates of PD-L1 positivity in MPE (56.7%) were higher than that in lung tissues (32.2%). All 27 discordant cases had higher scores in MPE. The double-staining method provided superior identification of PD-L1-positive tumor cells on a background with nonspecific staining. In conclusion, PD-L1 expression was moderately concordant between metastatic MPE cell blocks and matched primary lung carcinoma tissues, with variability related to tumor heterogeneity. MPE should be considered to detect PD-L1 when histological specimens are unattainable, especially when PD-L1 expression is >50%. PD-L1 positivity rates were higher in MPE. Double staining can improve PD-L1 detection by reducing false-negative/positive results.

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.

Prediction of Tumor PD-L1 Expression in Resectable Non-Small Cell Lung Cancer by Machine Learning Models Based on Clinical and Radiological Features: Performance Comparison With Preoperative Biopsy

OBJECTIVE

We investigated if PD-L1 expression can be predicted by machine learning using clinical and imaging features.

METHODS

We included 117 patients with c-stage I/II non-small cell lung cancer who underwent radical resection. A total of 3951 radiomic features were extracted by defining the tumor (within tumor contour), rim (contour ±3 mm) and exterior (contour +10 mm) on preoperative contrast computed tomography. After feature selection by Boruta algorithm, prediction models of tumor PD-L1 expression (22C3: ≥1%, <1%) of resected specimens were constructed using Random Forest: radiomics, clinical, and combined models. Their performance was evaluated by 5-fold cross-validation, and AUCs were compared using Delong test. Next, study groups were categorized as patients without biopsy (training set), and those with biopsy (test set). Predictive ability of biopsy was compared to each prediction model.

RESULTS

Of 117 patients (66 ± 10 years old, 48% male), 33 (28.2%) had PD-L1≥1%. Mean AUC of PD-L1≥1% for the validation set in radiomics, clinical, and combined models were 0.80, 0.80, and 0.83 (P = .32 vs. clinical model), respectively. The diagnosis of malignancy was made in 22 of 38 (58%) patients with attempted biopsies, and PD-L1 was measurable in 19 of 38 (50%) patients. Diagnostic accuracies of PD-L1≥1% from 19 determinable biopsies and 38 all attempted biopsies were 0.68 and 0.34, respectively. These were out performed by machine learning: 0.71, 0.71, and 0.74 for radiomics, clinical, and combined models, respectively.

CONCLUSIONS

Our machine learning could be an adjunctive tool in estimating PD-L1 expression prior to neoadjuvant treatment, particularly when PD-L1 is indeterminable with biopsy.

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.

The prognostic biological markers of immunotherapy for non-small cell lung cancer: current landscape and future perspective

The emergence of immunotherapy, particularly programmed cell death 1 (PD-1) and programmed cell death ligand-1 (PD-L1) produced profound transformations for treating non-small cell lung cancer (NSCLC). Nevertheless, not all NSCLC patients can benefit from immunotherapy in clinical practice. In addition to limited response rates, exorbitant treatment costs, and the substantial threats involved with immune-related adverse events, the intricate interplay between long-term survival outcomes and early disease progression, including early immune hyperprogression, remains unclear. Consequently, there is an urgent imperative to identify robust predictive and prognostic biological markers, which not only possess the potential to accurately forecast the therapeutic efficacy of immunotherapy in NSCLC but also facilitate the identification of patient subgroups amenable to personalized treatment approaches. Furthermore, this advancement in patient stratification based on certain biological markers can also provide invaluable support for the management of immunotherapy in NSCLC patients. Hence, in this review, we comprehensively examine the current landscape of individual biological markers, including PD-L1 expression, tumor mutational burden, hematological biological markers, and gene mutations, while also exploring the potential of combined biological markers encompassing radiological and radiomic markers, as well as prediction models that have the potential to better predict responders to immunotherapy in NSCLC with an emphasis on some directions that warrant further investigation which can also deepen the understanding of clinicians and provide a reference for clinical practice.

Efficacy of immunotherapy in oncogene-driven non-small-cell lung cancer

For advanced metastatic non-small-lung cancer, the landscape of actionable driver alterations is rapidly growing, with nine targetable oncogenes and seven approvals within the last 5 years. This accelerated drug development has expanded the reach of targeted therapies, and it may soon be that a majority of patients with lung adenocarcinoma will be eligible for a targeted therapy during their treatment course. With these emerging therapeutic options, it is important to understand the existing data on immune checkpoint inhibitors (ICIs), along with their efficacy and safety for each oncogene-driven lung cancer, to best guide the selection and sequencing of various therapeutic options. This article reviews the clinical data on ICIs for each of the driver oncogene defined lung cancer subtypes, including efficacy, both for ICI as monotherapy or in combination with chemotherapy or radiation; toxicities from ICI/targeted therapy in combination or in sequence; and potential strategies to enhance ICI efficacy in oncogene-driven non-small-cell lung cancers.

KRAS in NSCLC: State of the Art and Future Perspectives

In NSCLC, KRAS mutations occur in up to 30% of all cases, most frequently at codon 12 and 13. KRAS mutations have been linked to adenocarcinoma histology, positive smoking history, and Caucasian ethnicity, although differences have been described across KRAS mutational variants subtypes. KRAS mutations often concur with other molecular alterations, notably TP53, STK11, and KEAP1, which could play an important role in treatment efficacy and patient outcomes. For many years, KRAS mutations have been considered undruggable mainly due to a high toxicity profile and low specificity of compounds. Sotorasib and adagrasib are novel KRAS inhibitors that recently gained FDA approval for pre-treated KRAS mutant NSCLC patients, and other molecules such as GDC-6036 are currently being investigated with promising results. Despite their approval, the efficacy of these drugs is lower than expected and progression among responders has been reported. Mechanisms of acquired resistance to anti-KRAS molecules typically involves either on target secondary mutations (e.g., G12, G13, Q61H, R68S, H95, Y96C, V8L) or off-target alterations. Ongoing trials are currently evaluating strategies for implementing efficacy and overcoming acquired resistance to these compounds. Finally, the efficacy of immune-checkpoint inhibitors still needs to be completely assessed and responses to anti-PD-1/PD-L1 agents may strongly depend on concomitant mutations.

Efficacy of immune checkpoint inhibitors in non-small cell lung cancer: A systematic review and meta-analysis

Background

Immune checkpoint inhibitors (ICIs) have demonstrated remarkable efficacy in non-small cell lung cancer (NSCLC). However, only a minority of NSCLC patients benefit from ICIs, and whether the magnitude of benefit is specific factor-dependent remains unclear. We performed a systematic review to improve our understanding of clinicopathologic and biomolecular features associated with improved survival upon treatment with ICIs for NSCLC.

Methods

We searched PubMed, Web of Science, Embase, and Scopus from database inception to August 31, 2021, for randomized controlled trials (RCTs) comparing overall survival (OS) in NSCLC treated with ICIs vs control therapies. We calculated the pooled OS hazard ratio (HR) and 95% CI in subgroups using a random-effects model, and assessed the heterogeneity between the paired estimates using an interaction test.

Results

A total of 23 RCTs involving 15,829 patients were included. We found that wild-type EGFR, high PD-L1 expression, and high bTMB were associated with a significant OS benefit from ICIs, but not mutant EGFR, low PD-L1 expression, and low bTMB. The differences of OS benefit between wild-type and mutant EGFR (HR=1.53, 95%CI 1.13-2.08), high and low PD-L1 (HR=1.35; 95%CI 1.14-1.61), high and low bTMB (HR=1.71; 95%CI 1.17-2.52) were statistically significant. OS benefit was found in all subgroups regardless of sex, age, ECOG PS, histology, smoking history, baseline brain metastasis, race, and region, and the interaction test demonstrated no significant difference of the OS benefit between these opposed subgroups (e.g. male vs female).

Conclusions

Wild-type EGFR, high PD-L1 expression, and high bTMB are associated with a greater magnitude of efficacy from ICIs vs control therapies in NSCLC. However, the administration of ICIs should not be restricted to other clinicopathological factors (sex, smoking history, race, etc.).

PD-L1 Expression in Non-Small Cell Lung Cancer Specimens: Association with Clinicopathological Factors and Molecular Alterations

Immune checkpoint inhibitors (ICI) targeting programmed cell death-1 or its ligand (PD-L1) have improved outcomes in non-small cell lung cancer (NSCLC). High tumor PD-L1 expression, detected by immunohistochemistry (IHC) typically on formalin-fixed paraffin-embedded (FFPE) histological specimens, is linked to better response. Following our previous investigation on PD-L1 in cytological samples, the aim of this study was to further explore the potential impacts of various clinicopathological and molecular factors on PD-L1 expression. Two retrospective NSCLC cohorts of 1131 and 651 specimens, respectively, were investigated for PD-L1 expression (<1%/1−49%/≥50%), sample type, sample site, histological type, and oncogenic driver status. In both cohorts, PD-L1 was positive (≥1%) in 55% of the cases. Adenocarcinomas exhibited lower PD-L1 expression than squamous cell carcinomas (p < 0.0001), while there was no difference between sample types, tumor locations, or between the two cohorts in multivariate analysis (all p ≥ 0.28). Mutational status correlated significantly with PD-L1 expression (p < 0.0001), with the highest expression for KRAS-mutated cases, the lowest for EGFR-mutated, and the KRAS/EGFR wild-type cases in between. There was no difference in PD-L1 levels between different prevalent KRAS mutations (all p ≥ 0.44), while mucinous KRAS-mutated adenocarcinomas exhibited much lower PD-L1 expression than non-mucinous (p < 0.0001). Our data indicate that cytological and histological specimens are comparable for PD-L1 evaluation. Given the impact of KRAS mutations and the mucinous growth pattern on PD-L1 expression, these factors should be further investigated in studies on ICI response.

High programmed death ligand 1 expression in carcinomatous components predicts a poor prognosis in pulmonary pleomorphic carcinoma

PURPOSE

This study reviewed the clinicopathological characteristics and programmed death ligand 1 (PD-L1) expression of 46 patients with pulmonary pleomorphic carcinoma to better understand its clinical behavior and factors affecting the survival.

METHODS

Data of patients with pulmonary pleomorphic carcinomas resected in our institution were retrospectively reviewed. The tumors were classified as carcinomatous or sarcomatous according to the tissue components. Pathological characteristics were evaluated on hematoxylin and eosin-stained sections. The percentages of tumor cells with membrane staining for PD-L1 in carcinomatous and sarcomatous components were determined.

RESULTS

We reviewed data of 46 patients (41 males, 5 females; median age 70.5 years old, range 36-83 years old). Most patients with pulmonary pleomorphic carcinoma expressed PD-L1 (80.4%), and the proportion of PD-L1 expression in tumor cells was significantly higher in sarcomatous components than in carcinomatous components. In univariable analyses, high p-stage (III), necrosis on pathological findings, and high PD-L1 expression in carcinomatous components (≥ 50%) were poor prognostic factors for the overall survival. In multivariable analyses, high PD-L1 expression in carcinomatous components was significantly associated with a poor prognosis after surgery.

CONCLUSIONS

High PD-L1 expression in carcinomatous components was significantly associated with a poor prognosis after surgery.

Immune-Proteome Profiling in Classical Hodgkin Lymphoma Tumor Diagnostic Tissue

In classical Hodgkin Lymphoma (cHL), immunoediting via protein signaling is key to evading tumor surveillance. We aimed to identify immune-related proteins that distinguish diagnostic cHL tissues (=diagnostic tumor lysates, n = 27) from control tissues (reactive lymph node lysates, n = 30). Further, we correlated our findings with the proteome plasma profile between cHL patients (n = 26) and healthy controls (n = 27). We used the proximity extension assay (PEA) with the OlinkTM multiplex Immuno-Oncology panel, consisting of 92 proteins. Univariate, multivariate-adjusted analysis and Benjamini–Hochberg’s false discovery testing (=Padj) were performed to detect significant discrepancies. Proteins distinguishing cHL cases from controls were more numerous in plasma (30 proteins) than tissue (17 proteins), all Padj < 0.05. Eight of the identified proteins in cHL tissue (PD-L1, IL-6, CCL17, CCL3, IL-13, MMP12, TNFRS4, and LAG3) were elevated in both cHL tissues and cHL plasma compared with control samples. Six proteins distinguishing cHL tissues from controls tissues were significantly correlated to PD-L1 expression in cHL tissue (IL-6, MCP-2, CCL3, CCL4, GZMB, and IFN-gamma, all p ≤0.05). In conclusion, this study introduces a distinguishing proteomic profile in cHL tissue and potential immune-related markers of pathophysiological relevance.

Retrospective analysis of eleven gene mutations, PD-L1 expression and clinicopathological characteristics in non-small cell lung cancer patients

OBJECTIVES

To investigate the associations among expression of programmed cell death ligand 1 (PD-L1), eleven mutated genes, and clinicopathological characteristics in 273 patients with non-small cell lung cancer (NSCLC).

METHODS

We retrospectively examined tumor PD-L1 expression in 247 surgically resected primary and 26 advanced NSCLC patients by immunohistochemistry using SP263 antibody assay. Gene mutations of EGFR, TP53, KRAS, PIK3CA, ERBB2, MET, RET, ALK, BRAF, ROS1, and APC were examined by NGS sequence. Data analysis was carried out using SPSS 22.0. The associations among PD-L1 expression, eleven mutated genes and clinicopathological characteristics were assessed by univariate and multivariate analysis.

RESULTS

Among the total 273 patients, 68 (24.9%) patients were positive for PD-L1 expression. Data showed that mutated rate of EGFR gene was the highest with 63.0% (172/273), followed by TP53 (11.7%, 32/273) and KRAS (5.5%, 15/273). The female, non-smoker, and patients with adenocarcinoma (ADC) were more likely to have EGFR mutations. Multivariate logistic regression showed that PD-L1 expression was significantly associated with Non-ADC, lymphatic invasion, EGFR wild type and TP53 mutation (p = 0.041, <0.001, 0.004 and 0.014, respectively). Moreover, PD-L1 expression in adenocarcinoma was associated with lymphatic invasion, mutation of TP53 and KRAS gene (p = 0.012, <0.025 and 0.041, respectively).

CONCLUSIONS

Mutations of EGFR, KRAS and TP53 should be routinely detected in clinical practice to better guide the immunotherapy for NSCLC patients. Future investigations are warranted to illustrate the potential mechanisms between driver mutations and PD-L1 expression for guiding immunotherapy in patients with NSCLC.

Considerable interlaboratory variation in PD-L1 positivity in a nationwide cohort of non-small cell lung cancer patients

OBJECTIVES

Immunohistochemical expression of programmed death-ligand 1 (PD-L1) is used as a predictive biomarker for prescription of immunotherapy to non-small cell lung cancer (NSCLC) patients. Accurate assessment of PD-L1 expression is therefore crucial. In this study, the extent of interlaboratory variation in PD-L1 positivity in the Netherlands was assessed, using real-world clinical pathology data.

MATERIALS AND METHODS

Data on all NSCLC patients in the Netherlands with a mention of PD-L1 testing in their pathology report from July 2017 to December 2018 were extracted from PALGA, the nationwide network and registry of histo- and cytopathology in the Netherlands. PD-L1 positivity rates were determined for each laboratory that performed PD-L1 testing, with separate analyses for histological and cytological material. Two cutoffs (1% and 50%) were used to determine PD-L1 positivity. Differences between laboratories were assessed using funnel plots with 95% confidence limits around the overall mean.

RESULTS

6,354 patients from 30 laboratories were included in the analysis of histology data. At the 1% cutoff, maximum interlaboratory variation was 39.1% (32.7%-71.8%) and ten laboratories (33.3%) differed significantly from the mean. Using the 50% cutoff, four laboratories (13.3%) differed significantly from the mean and maximum variation was 23.1% (17.2%-40.3%). In the analysis of cytology data, 1,868 patients from 23 laboratories were included. Eight laboratories (34.8%) differed significantly from the mean in the analyses of both cutoffs. Maximum variation was 41.2% (32.2%-73.4%) and 29.2% (14.7%-43.9%) using the 1% and 50% cutoffs, respectively.

CONCLUSION

Considerable interlaboratory variation in PD-L1 positivity was observed. Variation was largest using the 1% cutoff. At the 50% cutoff, analysis of cytology data demonstrated a higher degree of variation than the analysis of histology data.

Efficacy of immunotherapy in KRAS-mutant non-small-cell lung cancer with comutations

KRAS-mutant non-small-cell lung cancer is the most common molecular driver of lung adenocarcinoma in western populations. No KRAS specific therapy has been approved by the US FDA until 2021. Despite significant heterogeneity in comutations, patients typically receive single-agent immunotherapy or chemoimmunotherapy as standard first-line therapy. It is unclear whether KRAS mutations predict outcomes with immunotherapy; however, there is emerging data suggesting improved outcomes in patients with a TP53 comutation and worse outcomes in patients with a STK11/LKB1 or KEAP1 comutation.

Prevalence and Heterogeneity of PD-L1 Expression by 22C3 Assay in Routine Population-Based and Reflexive Clinical Testing in Lung Cancer

INTRODUCTION

Programmed death-ligand 1 (PD-L1) is used as a biomarker for anti-programmed cell death protein-1 (PD-1) or anti-PD-L1 immunotherapies in NSCLC. We report here the results of population-based PD-L1 testing using the 22C3 IHC pharmDx Assay (Agilent Technologies) in a large Canadian regional reference pathology laboratory.

METHODS

Testing was conducted reflexively on biopsies and resections for NSCLC during an 8-month period. Tumor proportion score (TPS) cutoffs for low and high expression were 1% and 50%, respectively.

RESULTS

Altogether, 2031 PD-L1 tests were performed on specimens from 1795 patients, with 107 inconclusive results (5.3%). Excluding cases with inconclusive/missing data, proportions for the remaining 1713 patients were 41.6% for TPS less than 1%, 28.6% for TPS 1% to 49%, and 29.8% for TPS greater than or equal to 50%. Higher PD-L1 expression rates were noted in EGFR wild-type versus mutant tumors (p < 0.001), squamous versus adenocarcinoma (p < 0.001), and metastatic versus primary tumors (p < 0.001). PD-L1 among 103 patients with paired biopsy and resection specimens revealed moderate concordance (κ = 0.67). A total of 52% (25 of 48) of biopsies with TPS less than 1% had TPS greater than 1% in resection, whereas 84.6% (22 of 26) of biopsies with TPS greater than or equal to 50% were concordant in resected tumors. Discordance rates between biopsy and resection were 71.4% for biopsies with less than 8 mm² total area, compared with 33.3% for biopsies with greater than or equal to 8 mm² area (p < 0.026). Concordance among 27 patients with paired primary lung and metastatic tumor biopsies revealed only weak concordance (κ = 0.48).

CONCLUSIONS

Intratumoral heterogeneity of PD-L1 expression may result in misclassification of PD-L1 status in a substantial proportion of PD-L1-negative small biopsy samples. Biopsy of metastatic site may increase proportion of patients with high PD-L1 expression.

Impact of Programmed Death Ligand 1 Expression in Advanced Non-Small-Cell Lung Cancer Patients, Treated by Chemotherapy (GFPC 06-2015 Study)

Background

Few data have been published on the clinical and histopathological characteristics of advanced non-small–cell lung cancer (NSCLC) patients with high PD-L1 expression versus intermediate or none and the prognostic value of PD-L1 expression for patients treated with chemotherapy is unknown. This study was undertaken to prospectively assess the prognostic value of tumor-cell (TC) and immune-cell (IC) PD-L1 expressions for advanced NSCLC patients.

Methods

It was a prospective, multicenter study on advanced NSCLC patients, with performance status 0/1, scheduled, consecutively, to receive first-line platin-based chemotherapy. PD-L1 expression was determined immunochemically (Dako Autostainer and monoclonal antibody 22C3) and its impact on progression-free survival (PFS) and overall survival (OS) assessed.

Results

Among 198 patients screened in 19 centers, 140 were included median age: 66.5 ± 10 years; 76.4% men; 79.3% Caucasians; 10.7% nonsmokers; 63.6% adenocarcinomas; <1%, 1–50% and ≥50% TC PD-L1–expression rates were 47.1%, 25.7% and 27.2% of patients, respectively; respective null, intermediate and high rates on ICs were 35.7%, 38.6% and 25.7%. Second- and third-line chemotherapies were administered to 58.6% and 26.4% of the patients, respectively. None received immunotherapy. First-, second- and third-line median (95% CI) PFS lasted 4.6 (3.6–5.2), 3.7 (2.3–4.7) and 2.2 (1.5–4.3) months, respectively; median OS was 16.9 (11.4–19.9) months. No significant PFS and OS differences were observed according to TC or IC PD-L1 expression.

Conclusion

According to the results of this prospective, multicenter study, neither TC nor IC PD-L1 expression appears to be prognostic for chemotherapy-managed advanced NSCLC patients.

PD-L1 expression with respect to driver mutations in non-small cell lung cancer in an Asian population: a large study of 1370 cases in China

Background

Programmed cell death ligand 1 (PD-L1) expression with respect to genetic alternations has not been well established in non-small cell lung cancer (NSCLC), especially in the Asian population.

Methods

We reviewed 1370 NSCLC patients from a prospectively maintained database. Immunohistochemistry was performed on tumor cells and tumor-infiltrating lymphocytes (TILs) using the VENTANA (SP142) anti-PD-L1 antibody. The tumor proportion score (TPS) cutoff values were set at ⩾1% and ⩾50%, and the immune proportion score (IPS) cutoff values were set at ⩾1% and ⩾10%.

Results

In tumor cells, PD-L1 positivity was observed in 405 (29.6%), 122 (8.9%), and 27 (2.0%) patients with TPS cutoff values at ⩾1% and ⩾50%. Contrastingly, TILs of 1154 (84.2%) and 346 (25.3%) patients stained positive at IPS cutoff values of ⩾1% and ⩾50%, respectively. PD-L1 expression was more common in patients who were mutation-negative irrespective of the TPS cutoff values and tumor size. PD-L1 expression in tumor cells was less frequent in patients harboring EGFR mutations (18.8% TPS ⩾ 1% and 4.6% TPS ⩾ 50%). Conversely, PD-L1 expression was high in the presence of KRAS mutations (47.3% TPS ⩾ 1% and 22.5% TPS ⩾ 50%). Overall, KRAS, BRAF, PICK3A, MET mutations and ROS1 and RET translocations were more frequent, while EGFR and HER2 mutations and ALK translocations were less frequent compared with the overall PD-L1 expression levels. Although the difference between TILs among the PD-L1-positive cases was comparatively small, PD-L1 positivity was less prevalent in EGFR-mutated tumors and more common in those with KRAS mutations, ROS1 translocations, BRAF mutations, or MET mutations.

Conclusion

Our study showed the heterogeneity in PD-L1 expression with respect to nine major oncogenic drivers in China. Future studies are warranted to further clarify the association between PD-L1 expression and driver mutations in NSCLC.

Cytology cell blocks from malignant pleural effusion are good candidates for PD-L1 detection in advanced NSCLC compared with matched histology samples

BACKGROUND

Detection of programmed cell death ligand-1 (PD-L1) by immunohistochemistry (IHC) has been commonly used to predict the efficacy of treatment with PD-1/PD-L1 inhibitors. However, there is limited literature regarding the reliability of PD-L1 testing using malignant pleural effusion (MPE) cell blocks. Here, we assess PD-L1 expression in sections from MPE cell blocks and evaluate the value of IHC double staining in the interpretation of PD-L1 expression.

METHODS

In all, 124 paired formalin-fixed tissues from advanced NSCLC patients, including MPE cell blocks and matched histology samples, were included. PD-L1 expression was assessed using the SP263 assay, and the tumor proportion score (TPS) and the staining intensity were evaluated. PD-L1 staining results were also compared between IHC double and single staining techniques.

RESULTS

PD-L1 expression was concordant in most paired cases (86/101, 85.1%) among three TPS cut-offs (<1%, 1-49% and ≥ 50%), with a kappa value of 0.774. Moreover, a significant difference in PD-L1 expression between MPE cell blocks and biopsy samples was observed (p = 0.005). For the 15 discordant pairs, 13 MPE cell block samples showed increased expression of PD-L1. Compared with the standard IHC single PD-L1 assay, double staining with anti-TTF-1 and anti-PD-L1 revealed a negative effect on PD-L1 expression testing and resulted in weaker staining intensity and a lower TPS (p = 0.000).

CONCLUSIONS

MPE cell block samples are good candidates for PD-L1 expression detection in advanced NSCLC patients. The mechanism and clinical significance of the higher PD-L1 expression rate in MPE cell blocks compared with small biopsy samples remain to be evaluated prospectively.

RAD51Bme Levels as a Potential Predictive Biomarker for PD-1 Blockade Response in Non-Small Cell Lung Cancer

Lung cancer (LC) cells frequently express high levels of programmed death-ligand 1 (PD-L1). Although these levels grossly correlate with the likelihood of response to specific checkpoint inhibitors, the response prediction is rather imperfect, and more accurate predictive biomarkers are mandatory. We examined the methylation profile of RAD51B (RAD51B^me) as a candidate predictive biomarker for anti-PD-1 therapy efficacy in non-small cell lung cancer (NSCLC), correlating with patients’ outcome. PD-L1 immunoexpression and RAD51B^me levels were analysed in NSCLC samples obtained from patients not treated with anti-PD-1 (Untreated Cohort (#1)) and patients treated with PD-1 blockade (Treated Cohort (#2)). Of a total of 127 patients assessed, 58.3% depicted PD-L1 positivity (PD-L1⁺). RAD51B^me levels were significantly associated with PD-L1 immunoexpression. Patients with PD-1 blockade clinical benefit disclosed higher RAD51B^me levels (p = 0.0390) and significantly lower risk of disease progression (HR 0.37; 95% CI: 0.15–0.88; p = 0.025). Combining RAD51B^me+ with PD-L1⁺ improved the sensitivity of the test to predict immunotherapy response. PD-L1⁺ was also associated with lower risk of death (HR 0.35; 95% CI: 0.15–0.81; p = 0.014). Thus, RAD51B^me levels might be combined with validated predictive biomarker PD-L1 immunostaining to select patients who will most likely experience clinical benefit from PD-1 blockade. The predictive value of RAD51B^me should be confirmed in prospective studies.

Is there any correlation between spectral CT imaging parameters and PD-L1 expression of lung adenocarcinoma?

Background

The aim of this study was to explore whether spectral computed tomography (CT) imaging parameters are associated with PD‐L1 expression of lung adenocarcinoma.

Methods

Spectral CT imaging parameters (iodine concentrations [IC] of lesion in arterial phase [ICLa] and venous phase [ICLv], normalized IC [NICa/NICv]‐normalized to the IC in the aorta, slope of the spectral HU curve [λHUa/λHUv] and enhanced monochromatic CT number [CT40keVa/v, CT70keVa/v] on 40 and 70 keV images) were analyzed in 34 prospectively enrolled lung adenocarcinoma patients with common molecular pathological markers including PD‐L1 expression detected with immunohistochemistry. Patients were divided into two groups: positive PD‐L1 expression and negative PD‐L1 expression groups. Two‐sample Mann‐Whitney U test was used to test the difference of spectral CT imaging parameters between the two groups.

Results

The CT40keVa (127.03 ± 37.92 vs. −54.69 ± 262.04), CT40keVv (124.39 ± 34.71 vs. −45.73 ± 238.97), CT70keVa (49.56 ± 11.76 vs. −136.51 ± 237.08) and CT70keVv (46.13 ± 15.81 vs. −133.10 ± 230.72) parameters in the positive PD‐L1 expression group of lung adenocarcinoma were significantly higher than the negative PD‐L1 expression group (all P < 0.05). There was no difference detected in IC, NIC and λHU of the arterial and venous phases between both groups (all P > 0.05).

Conclusion

CT40keVa, CT40keVv, CT70keVa and CT70keVv were increased in positive PD‐L1 expression. These parameters may be used to distinguish the PD‐L1 expression state of lung adenocarcinoma.

Association of PD-L1 expression in oral squamous cell carcinoma with smoking, sex, and p53 expression

OBJECTIVES

The aim of this study was to investigate the association between oral cavity squamous cell carcinoma (OSCC) and PD-L1 expression, and smoking, and p53 expression.

STUDY DESIGN

Histologic review of archival slides of patients with OSCC, obtained from the Sydney Head and Neck Cancer Institute database from 1995 to 2015, was undertaken with tissue microarray construction and immunohistochemistry to identify PD-L1 and p53 expression.

RESULTS

Of the 255 patients identified, PD-L1 expression was observed in 70 (27.5%) and more commonly in females (odds ratio [OR] = 2.19; P = .005). PD-L1 expression of 1% or greater was associated with p53 expression (P = .019) and associated with absence of smoking (P = .06). PD-L1 expression, at 1%, was not significantly associated with overall survival (P = .482), disease-specific survival (P = .864), and disease-free survival (P = .731).

CONCLUSIONS

Our data demonstrate that PD-L1 expression of 1% or greater is more frequent in OSCC in females, nonsmokers, and in patients with p53-positive OSCC. These findings have important implications for immune therapy for OSCC.

Positive PD-L1 expression is predictive for patients with advanced EGFR wild-type non-small cell lung cancer treated with gemcitabine and cisplatin

This retrospective study aimed to investigate the association between programmed death ligand-1 (PD-L1) expression and the clinicopathological characteristics of patients with advanced epidermal growth factor receptor (EGFR) wild-type non-small cell lung cancer (NSCLC). The predictive role and cut-off value of PD-L1 expression was subsequently investigated. A total of 172 patients with advanced EGFR wild-type NSCLC were enrolled. All patients received platinum-based doublet chemotherapy (gemcitabine plus cisplatin). PD-L1 expression in lung tissues was assessed using immunohistochemical methods. The χ² test was used to analyze the association between PD-L1 expression and clinicopathological characteristics. Survival time analysis was performed using the Kaplan-Meier method. The two groups, positive PD-L1 expression and negative PD-L1 expression, were compared using the log-rank test. Multivariate analysis using the Cox proportional hazard regression model was conducted to determine prognostic factors for overall survival (OS) and progression-free survival (PFS) times. Positive PD-L1 expression was observed in 48.3% (84/172), 40.7% (70/172), 21.5% (37/172) and 8.1% (14/172) of patients when using cut-off values of 1, 5, 10 and 50%, respectively. The χ² test revealed that elevated pretreatment C-reactive protein (CRP) level and cancer stage IV were significantly associated with positive PD-L1 expression. The OS and PFS of positive PD-L1 (1, 5, 10 and 50% cut-off) expression group were shorter compared with the negative PD-L1 (1, 5, 10 and 50% cut-off) expression group. Multivariate survival analysis revealed that PD-L1 expression ≥50% was significantly associated with decreased OS and PFS [OS time, P=0.001; hazard ratio (HR), 2.768; 95% confidence interval (CI), 1.551–4.940; PFS time, P=0.002; HR, 2.537; 95% CI, 1.423–4.524]. These results indicated that positive PD-L1 (50% cut-off) expression was an independent predictor of poor prognosis for patients with advanced NSCLC treated with gemcitabine plus cisplatin. PD-L1 expression was associated with CRP level and cancer stage. The results obtained in the present study suggest that positive PD-L1 expression serves a prognostic role in advanced NSCLC and that the optimal cut-off value may be 50%.

Recent Findings in the Regulation of Programmed Death Ligand 1 Expression

With the recent approvals for the application of monoclonal antibodies that target the well-characterized immune checkpoints, immune therapy shows great potential against both solid and hematologic tumors. The use of these therapeutic monoclonal antibodies elicits inspiring clinical results with durable objective responses and improvements in overall survival. Agents targeting programmed cell death protein 1 (PD-1; also known as PDCD1) and its ligand (PD-L1) achieve a great success in immune checkpoints therapy. However, the majority of patients fail to respond to PD-1/PD-L1 axis inhibitors. Expression of PD-L1 on the membrane of tumor and immune cells has been shown to be associated with enhanced objective response rates to PD-1/PD-L1 inhibition. Thus, an improved understanding of how PD-L1 expression is regulated will enable us to better define its role as a predictive marker. In this review, we summarize recent findings in the regulation of PD-L1 expression.

Heterogeneous tumor features and treatment outcome between males and females with lung cancer (LC): Do gender and sex matter?

Lung cancer (LC) is the leading cause of cancer-related death worldwide, despite a decreasing incidence rate in recent years, especially in men. Most risk factors for LC could be linked to an individual's reproductive system and secondary sex characteristics ('sex-related') and/or to some physical, behavioral and personality traits ('gender-related') peculiar to males rather than females or vice versa. An imbalance of these etiologic factors could explain why some LC features may differ between sexes. For this review, an extended literature data collection was performed, using keywords to identify 'sex/gender' and 'LC'. Differences between genders in LC epidemiology, pathological and molecular characteristics, loco-regional and/or systemic treatments outcome and prognosis were systematically analyzed. The possible predictive role of physio-pathological factors in males and females paves the way for a personalized therapeutic approach, emphasizing the need to include gender as a stratification factor in future clinical trials design.

Cerebral Thromboembolism after Lobectomy for Lung Cancer: Pathological Diagnosis and Mechanism of Thrombus Formation

Lung cancer is the leading cause of cancer-related deaths worldwide. Although molecular therapies have emerged as efficacious strategies for the treatment of lung cancer, surgical resection is still recommended as a radical therapeutic option. Currently, lobectomy is regarded as the most reliable radical treatment of primary lung cancer. Among the various complications after lobectomy, cerebral thromboembolism requires attention as a life-threatening complication during the early postoperative period. It occurs in 0.2–1.2% of surgical cases of lung cancer and typically develops following left upper lobectomy with a long pulmonary vein stump (PVS). PVS-associated thrombosis is known to cause cerebral thromboembolism after such procedures; however, distinguishing this specific complication from that caused by postoperative atrial fibrillation is challenging. We summarize herein the diagnostic pathology of thrombus formation in accordance with its thrombogenic mechanism. We focus on the potential utility of the pathological assessment of thrombectomy specimens. The morphological information obtained from these specimens enables the presumption of thrombogenic etiology and provides useful clues to both select an appropriate pharmacotherapy and determine a follow-up treatment for cerebral thromboembolism.

Disparities and Trends in Genetic Testing and Erlotinib Treatment among Metastatic Non-Small Cell Lung Cancer Patients

BACKGROUND

Despite reports of socioeconomic disparities in rates of genetic testing and targeted therapy treatment for metastatic non-small cell lung cancer (NSCLC), little is known about whether such disparities are changing over time.

METHODS

We performed a retrospective analysis to identify disparities and trends in genetic testing and treatment with erlotinib. Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we identified 9,900 patients with stage IV NSCLC diagnosed in 2007 to 2011 at age 65 or older. We performed logistic regression analyses to identify patient factors associated with odds of receiving a genetic test and erlotinib treatment, and to assess trends in these differences with respect to diagnosis year.

RESULTS

Patients were more likely to receive genetic testing if they were under age 75 at diagnosis [odds ratio (OR), 1.55] independent of comorbidity level, and this age-based gap showed a decrease over time (OR, 0.93). For untested patients, erlotinib treatment was associated with race (OR, 0.58, black vs. white; OR, 2.45, Asian vs. white), and was more likely among female patients (OR, 1.45); for tested patients, erlotinib treatment was less likely among low-income patients (OR, 0.32). Most of these associations persisted or increased in magnitude.

CONCLUSIONS

Race and sex are associated with rates of erlotinib treatment for patients who did not receive genetic testing, and low-income status is associated with treatment rates for those who did receive testing. The racial disparity remained stable over time, while the income-based disparity grew larger.

IMPACT

Attention to reducing disparities is needed as precision cancer treatments continue to be developed.

Effect of Gender on the Outcome of Patients Receiving Immune Checkpoint Inhibitors for Advanced Cancer: A Systematic Review and Meta-Analysis of Phase III Randomized Clinical Trials

Evidence has recently emerged on the influence of gender on the immune system. In this systematic review and meta-analysis of phase III randomized clinical trials (RCTs), we explored the impact of gender on survival in patients with advanced cancer treated with immune checkpoint inhibitors (ICIs). We performed a comprehensive search of the literature updated to April 2018, including the Cochrane Central Register of Controlled Trials, PubMed, and EMBASE. We extracted data on study characteristics and risk of bias in duplicate. Of 423 unique citations, 21 RCTs were included, inherently to 12,635 patients. Both males and females showed reduced risk of death associated with ICIs use (HR 0.73, p < 0.001 and HR 0.77, p < 0.001, respectively). Subgroup analyses by specific ICI showed similar OS in both genders for anti-PD-1/PDL-1. Anti-CTLA-4 use was associated with longer OS in men only (HR 0.77, p < 0.012), with the exception of melanoma (in women, HR 0.80, p = 0.006). PFS was longer in men than in women (HR 0.67, p < 0.001 and HR 0.77, p = 0.100, respectively). Conclusively, ICIs use was associated with more favorable outcomes in men, particularly for anti-CTLA-4 agents. In melanoma, not gender-related factors may influence the anti-tumor immune response evoked by ICIs.

Predictive value of oncogenic driver subtype, programmed death-1 ligand (PD-L1) score, and smoking status on the efficacy of PD-1/PD-L1 inhibitors in patients with oncogene-driven non-small cell lung cancer

BACKGROUND

This multicenter, retrospective study explored the value of oncogene driver subtype, programmed death-1 ligand (PD-L1) status, and smoking status for predicting which patients with oncogene-driven non-small cell lung cancer (NSCLC) would benefit from treatment with programmed death-1 (PD-1)/PD-L1 inhibitors.

METHODS

The clinical features, PD-L1 tumor proportion scores, and PD-1/PD-L1 inhibitor (PDi) outcomes (objective response rate and progression-free survival) of patients who had advanced NSCLC with Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) mutations or common, actionable oncogenic drivers were captured.

RESULTS

In total, 189 oncogene-positive patients were analyzed. Of these, 104 received a PDi, and 108 had undergone prior PD-L1 testing. The frequency of PD-L1 positivity (≥1%) was higher in patients who had KRAS mutations (P = .031), smokers (P = .006), and non-Asian patients (P = .002). Multivariable analysis indicated that smoking status (P < .001) was the only factor associated significantly with KRAS mutation. The objective response rate to PDi treatment was 16.9% (11 of 65 patients) among smokers (17.3% in the KRAS-mutant and 15.4% in the non-KRAS-mutant smoker subgroups), which was significantly higher than the 0% rate (0 of 26 patients; P = .019) among never-smokers. In subgroup analyses, progression-free survival was influenced by KRAS mutation status (median, 4.57 vs 1.63 months; P = .004), smoking status (4.07 vs 1.73 months; P = .004), PD-L1 positivity (3.8 vs 1.2 months; P = .040), and non-Asian race (3.0 vs 1.97 months; P = .046). In multivariable analysis, only smoking status (P = .008) remained a significant predictor when a PD-L1 level ≥1% was used. However, both smoking status (P = .001) and PD-L1 status (P = .028) were independent predictors when a PD-L1 level ≥50% was used.

CONCLUSIONS

Among associated clinical features among patients who have NSCLC with oncogenic drivers, smoking status potentially was the most important, easily available predictor of single PDi efficacy.

Sensitive Detection of Exosomal Proteins via a Compact Surface Plasmon Resonance Biosensor for Cancer Diagnosis

Exosomes are small extracellular vesicles released by cells for cell-cell communication. They play important roles in cancer development, metastasis, and drug resistance. Exosomal proteins have been demonstrated by many studies as promising biomarkers for cancer screening, diagnosis, and monitoring. Among many detection techniques, surface plasmon resonance (SPR) is a highly sensitive, label-free, and real-time optical detection method. Commercial prism-based wavelength/angular-modulated SPR sensors afford high sensitivity and resolution, but their large footprint and high cost limit their adaptability for clinical settings. Recently, a nanoplasmonic exosome (nPLEX) assay was developed to detect exosomal proteins for ovarian cancer diagnosis. However, comparing with conventional SPR biosensors, the broad applications of nanoplasmonic biosensors are limited by the difficult and expensive fabrication of nanostructures. We have developed an intensity-modulated, compact SPR biosensor (25 cm × 10 cm × 25 cm) which uses a conventional SPR sensing mechanism and does not require nanostructure fabrication. Calibration from glycerol showed that the compact SPR biosensor offered sensitivity of 9.258 × 10³%/RIU and resolution of 8.311 × 10^-6 RIU. We have demonstrated the feasibility of the compact SPR biosensor in lung cancer diagnosis using exosomal epidermal growth factor receptor (EGFR) and programmed death-ligand 1 (PD-L1) as biomarkers. It detected a higher level of exosomal EGFR from A549 nonsmall cell lung cancer (NSCLC) cells than BEAS-2B normal cells. With human serum samples, the compact SPR biosensor detected similar levels of exosomal EGFR in NSCLC patients and normal controls, and higher expression of exosomal PD-L1 in NSCLC patients than normal controls. The compact SPR biosensor showed higher detection sensitivity than ELISA and similar sensing accuracy as ELISA. It is a simple and user-friendly sensing platform, which may serve as an in vitro diagnostic test for cancer.

Biomarkers for predicting efficacy of PD-1/PD-L1 inhibitors

Programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) is a negative modulatory signaling pathway for activation of T cell. It is acknowledged that PD-1/PD-L1 axis plays a crucial role in the progression of tumor by altering status of immune surveillance. As one of the most promising immune therapy strategies, PD-1/PD-L1 inhibitor is a breakthrough for the therapy of some refractory tumors. However, response rate of PD-1/PD-L1 inhibitors in overall patients is unsatisfactory, which limits the application in clinical practice. Therefore, biomarkers which could effectively predict the efficacy of PD-1/PD-L1 inhibitors are crucial for patient selection. Biomarkers reflecting tumor immune microenvironment and tumor cell intrinsic features, such as PD-L1 expression, density of tumor infiltrating lymphocyte (TIL), tumor mutational burden, and mismatch-repair (MMR) deficiency, have been noticed to associate with treatment effect of anti-PD-1/anti-PD-L1 therapy. Furthermore, gut microbiota, circulating biomarkers, and patient previous history have been found as valuable predictors as well. Therefore establishing a comprehensive assessment framework involving multiple biomarkers would be meaningful to interrogate tumor immune landscape and select sensitive patients.