Assessment of the PD-L1 status by immunohistochemistry: challenges and perspectives for therapeutic strategies in lung cancer patients

Prognostic and predictive role of YKL-40 in anal squamous cell carcinoma: a serological and tissue-based analysis in a multicentric cohort

Introduction

Anal squamous cell carcinoma (ASC) is a rare gastrointestinal malignancy showing an increased incidence over the past decades. YKL-40 is an immune modulator and pro-angiogenetic factor that showed a promising prognostic and predictive potential in several malignancies, but limited data are available for ASC. This study aims to provide an extensive evaluation of the prognostic and predictive role of YKL-40 in a multicenter cohort of ASC patients.

Methods

We retrospectively retrieved 72 consecutive cases of ASC diagnosed between February 2011 and March 2021. Both serum and tissue protein expression of YKL-40 were assessed, the latter in ASC tumor cells and peritumor immune cells.

Results

Increased YKL-40 serum levels at the time of diagnosis were associated with older age (p = 0.035), presence of cardiovascular/metabolic comorbidities (p = 0.007), and death for any cause (p = 0.011). In addition, high serum levels of YKL-40 were associated with a poor prognosis (HR: 2.82, 95% CI: 1.01-7.84; p = 0.047). Protein expression of YKL-40 in ASC tumor cells was significantly associated with low tumor grade (p = 0.031), while the increased expression in peritumor immune cells was associated with a worse response of patients to chemoradiotherapy (p = 0.007). However, YKL-40 protein expression in ASC tumor cells or peritumor immune cells did not significantly impact patient overall survival.

Discussion

In conclusion, YKL-40 resulted a relevant prognostic (serum level) and predictive (tissue protein expression in peritumor immune cells) biomarker and can considerably improve ASC patient clinical management.

Noninvasively Deciphering the Immunosuppressive Tumor Microenvironment Using Galectin-1 PET to Inform Immunotherapy Responses

Immune checkpoint blockade (ICB) has achieved groundbreaking results in clinical cancer therapy; however, only a subset of patients experience durable benefits. The aim of this study was to explore strategies for predicting tumor responses to optimize the intervention approach using ICB therapy. Methods: We used a bilateral mouse model for proteomics analysis to identify new imaging biomarkers for tumor responses to ICB therapy. A PET radiotracer was synthesized by radiolabeling the identified biomarker-targeting antibody with 124I. The radiotracer was then tested for PET prediction of tumor responses to ICB therapy. Results: We identified galectin-1 (Gal-1), a member of the carbohydrate-binding lectin family, as a potential negative biomarker for ICB efficacy. We established that Gal-1 inhibition promotes a sensitive immune phenotype within the tumor microenvironment (TME) for ICB therapy. To assess the pre-ICB treatment status of the TME, a Gal-1-targeted PET radiotracer, 124I-αGal-1, was developed. PET imaging with 124I-αGal-1 showed the pretreatment immunosuppressive status of the TME before the initiation of therapy, thus enabling the prediction of ICB resistance in advance. Moreover, the use of hydrogel scaffolds loaded with a Gal-1 inhibitor, thiodigalactoside, demonstrated that a single dose of thiodigalactoside-hydrogel significantly potentiated ICB and adoptive cell transfer immunotherapies by remodeling the immunosuppressive TME. Conclusion: Our study underscores the potential of Gal-1-targeted PET imaging as a valuable strategy for early-stage monitoring of tumor responses to ICB therapy. Additionally, Gal-1 inhibition effectively counteracts the immunosuppressive TME, resulting in enhanced immunotherapy efficacy.

Comprehensive molecular analysis of driver mutations in non-small cell lung carcinomas and its correlation with PD-L1 expression, An Indian perspective

BACKGROUND

The understanding of molecular mechanisms involved in non-small cell lung carcinoma (NSCLC) has revolutionized significantly in the recent years. These have helped to develop personalized management strategies by identifying specific molecular alterations such as mutations in EGFR, ROS1, BRAF, ERBB2, MET, ALK, and KRAS genes. These mutations are targetable ensuring a better clinical outcome. Next-generation sequencing (NGS) methodology is the recommended technique for the identification of driver mutations in the five hot-spot genes (EGFR, ALK, ROS1, MET, and BRAF) involved in the NSCLC. NGS has numerous advantages including multiplexing, tissue conservation, identification of rare and novel variants, and reduced cost over the sequential single gene testing. Herein, we sought to demonstrate the mutational profile in NSCLC and their clinicopathologic correlation in a contemporary cohort of Indian NSCLC patients. Additionally, we studied the correlation of oncogenic driver mutations with PD-L1 status in these patients.

MATERIALS AND METHODS

Five fifty-two stage IV NSCLC patients (adenocarcinoma=490; squamous cell carcinoma=51; adenosquamous carcinoma=5; large cell carcinoma=2; sarcomatoid carcinoma=3; spindle cell carcinoma=1) underwent broad molecular profiling by a custom-made, targeted DNA- and RNA-based five hot-spot genes lung cancer panel (EGFR, ALK, ROS1, BRAF, and MET), compatible with the NGS Ion S5 system. The mutations were correlated with the clinicopathologic characteristics. Additionally, PD-L1 expression status, available on 252 tumors, was correlated with the oncogenic drivers.

RESULTS

Validation of the 5 gene panel yielded the following results: a) specificity of 99.74%; b) sensitivity of 100% for single nucleotide variants (SNVs) (>5% variant allele frequency, VAF), indels (>10% VAF) and fusions; c) 100% intra- and inter-run reproducibility; d) 88% inter-laboratory agreement. Validated panel was then used to analyze clinical samples. Sixty percentage tumors harbored either one (54.71%) or multiple (3.26%) mutations. EGFR and BRAF V600E mutations, ALK and ROS1 rearrangements, and MET exon 14 skipping mutation were observed in 38.41% (n = 212) and 2.72% (n = 15) patients, 12.14% (n = 67) and 3.62% (n = 20) patients, and 1.09% (n = 6) patients, respectively. EGFR exon 19 deletion accounted for 52.83% of all mutations, followed by L858R (35.85%), T790M (5.19%), exon 20 insertions (6.6%), and other rare mutations (G719X, L861Q, S768I) (9.91%). Concurrent EGFR with ALK, EGFR with ROS1, EGFR with MET, and EGFR with BRAF were observed in 10, 4, 1, and 3 patients, respectively. PD-L1 was expressed in 134 patients (53.2%). Exon 19 deletion was more prevalent in PD-L1 negative tumors whereas exon 21 substitution (L858R) was seen more in PD-L1 positive tumors.

CONCLUSIONS

This is one of the largest cohorts of NSCLC for comprehensive targeted mutational profiling and correlation with the PD-L1 expression. The mutations are more prevalent in non-smoker females for all genes, except ALK (non-smoker males). MET and BRAF mutations are more common in elderly population whereas EGFR mutations, and ALK and ROS1 genes rearrangements are more prevalent in younger population. The most common histopathologic subtype/feature associated with various mutations was as follows: acinar with EGFR, solid with ALK, macronucleoli with ROS1, signet ring with MET, and micropapillary with BRAF.

Prediction of prognosis of patients with hepatocellular carcinoma based on immune-related score

BACKGROUND

Immune-related scores are currently used for prognostic evaluation and as an immunotherapy reference in various cancers. However, the relationship between immune-related score and hepatocellular carcinoma (HCC) prognosis has not yet been investigated. This study aimed to explore the clinical application value of immune-related score for predicting HCC prognosis-related indicators including disease-free survival (DFS) and overall survival (OS), and to construct a clinical nomogram prediction model related to verification.

METHODS

This study included 284 HCC patients who were selected from the Cancer Genome Atlas (TCGA) database and linked to the immune-related score downloaded from the public platform. A Cox proportional hazards regression model was used to estimate the adjusted risk ratio, and a nomogram was constructed based on multivariate analysis results and clinical significance. The model was internally verified by bootstrap. The performance of the prediction model was evaluated using the C-index and calibration curves.

RESULTS

Patients were divided into three subgroups according to the immune-related score level. Compared with patients in the low immune-related score group, the DFS of patients in the medium and high immune-related score groups was significantly prolonged (HR: 0.53, 95% CI: 0.32-0.87; HR: 0.37, 95% CI: 0.21-0.63, respectively). The OS of patients in the medium and high immune-related score groups was also significantly prolonged (HR: 0.43, 95% CI: 0.20-0.95, p = 0.038; HR: 0.29, 95% CI: 0.14-0.58, p < 0.001, respectively). The C-indexes for predicting DFS and OS were 0.687 (95% CI: 0.665-0.700) and 0.743 (95% CI: 0.709-0.776), respectively. The calibration curves of 3-year and 5-year DFS and OS showed that the results predicted by the nomogram were in good agreement with the actual observations.

CONCLUSIONS

Moderate/high-grade immune-related score was significantly associated with better DFS and OS in HCC patients. In addition, a nomogram for prognosis estimation can help clinicians predict the survival status of patients.

In vivo quantification of programmed death-ligand-1 expression heterogeneity in tumors using fluorescence lifetime imaging

Cancer patient selection for immunotherapy is often based on programmed death-ligand-1 (PD-L1) expression as a biomarker. PD-L1 expression is currently quantified using immunohistochemistry, which can only provide snapshots of PD-L1 expression status in microscopic regions of ex vivo specimens. In vivo imaging using targeted agents can capture dynamic variations of PD-L1 expression in entire tumors within and across multiple subjects. Towards this goal, several PD-L1 targeted molecular imaging probes have been evaluated in murine models and humans. However, clinical translation of these probes has been limited due to a significant non-specific accumulation of the imaging probes and the inability of conventional imaging modalities to provide quantitative readouts that can be compared across multiple subjects. Here we report that in vivo time-domain (TD) fluorescence imaging can provide quantitative estimates of baseline tumor PD-L1 heterogeneity across untreated mice and variations in PD-L1 expression across mice undergoing clinically relevant anti-PD1 treatment. This approach relies on a significantly longer fluorescence lifetime (FLT) of PD-L1 specific anti-PD-L1 antibody tagged to IRDye 800CW (αPDL1-800) compared to nonspecific αPDL1-800. Leveraging this unique FLT contrast, we show that PD-L1 expression can be quantified across mice both in superficial breast tumors using planar FLT imaging, and in deep-seated liver tumors (>5 mm depth) using the asymptotic TD algorithm for fluorescence tomography. Our results suggest that FLT contrast can accelerate the preclinical investigation and clinical translation of novel molecular imaging probes by providing robust quantitative readouts of receptor expression that can be readily compared across subjects.

Quantitative multiplexed imaging technologies for single-cell analysis to assess predictive markers for immunotherapy in thoracic immuno-oncology: promises and challenges

The past decade has witnessed a revolution in cancer treatment by the shift from conventional drugs (chemotherapies) towards targeted molecular therapies and immune-based therapies, in particular the immune-checkpoint inhibitors (ICIs). These immunotherapies selectively release the host immune system against the tumour and have shown unprecedented durable remission for patients with cancers that were thought incurable such as advanced non-small cell lung cancer (aNSCLC). The prediction of therapy response is based since the first anti-PD-1/PD-L1 molecules FDA and EMA approvals on the level of PD-L1 tumour cells expression evaluated by immunohistochemistry, and recently more or less on tumour mutation burden in the USA. However, not all aNSCLC patients benefit from immunotherapy equally, since only around 30% of them received ICIs and among them 30% have an initial response to these treatments. Conversely, a few aNSCLC patients could have an efficacy ICIs response despite low PD-L1 tumour cells expression. In this context, there is an urgent need to look for additional robust predictive markers for ICIs efficacy in thoracic oncology. Understanding of the mechanisms that enable cancer cells to adapt to and eventually overcome therapy and identifying such mechanisms can help circumvent resistance and improve treatment. However, more than a unique universal marker, the evaluation of several molecules in the tumour at the same time, particularly by using multiplex immunostaining is a promising open room to optimise the selection of patients who benefit from ICIs. Therefore, urgent further efforts are needed to optimise to individualise immunotherapy based on both patient-specific and tumour-specific characteristics. This review aims to rethink the role of multiplex immunostaining in immuno-thoracic oncology, with the current advantages and limitations in the near-daily practice use.

Bispecific antibody targeting TGF-β and PD-L1 for synergistic cancer immunotherapy

The PD-1/PD-L1 signaling pathway plays a crucial role in cancer immune evasion, and the use of anti-PD-1/PD-L1 antibodies represents a significant milestone in cancer immunotherapy. However, the low response rate observed in unselected patients and the development of therapeutic resistance remain major obstacles to their clinical application. Accumulating studies showed that overexpressed TGF-β is another immunosuppressive factor apart from traditional immune checkpoints. Actually, the effects of PD-1 and TGF-β pathways are independent and interactive, which work together contributing to the immune evasion of cancer cell. It has been verified that blocking TGF-β and PD-L1 simultaneously could enhance the efficacy of PD-L1 monoclonal antibody and overcome its treatment resistance. Based on the bispecific antibody or fusion protein technology, multiple bispecific and bifunctional antibodies have been developed. In the preclinical and clinical studies, these updated antibodies exhibited potent anti-tumor activity, superior to anti-PD-1/PD-L1 monotherapies. In the review, we summarized the advances of bispecific antibodies targeting TGF-β and PD-L1 in cancer immunotherapy. We believe these next-generation immune checkpoint inhibitors would substantially alter the cancer treatment paradigm, especially in anti-PD-1/PD-L1-resistant patients.

Matched tissue and liquid biopsies for advanced non-small cell lung cancer patients A potentially indispensable complementary approach

The introduction of liquid biopsies (LB) has brought forth a number of therapeutic opportunities into the domain of thoracic oncology. Many of which have been adopted for care of patients presenting with advanced non-squamous non-small cell lung cancer (aNS-NSCLC). For example, one of the most frequent indications to perform a LB in these patients, at least in Europe, is for patients treated with tyrosine kinase inhibitors (TKIs) targeting EGFR and ALK genomic alterations when the tumor progresses. A tissue biopsy (TB) must then be taken, ideally from a site of a tumor that progresses, in particular if the LB does not permit detection of a mechanism of resistance to TKI. A LB from a patient with aNS-NSCLC is recommended before first-line therapy if no tissue and/or cytological material is accessible or if the extracted nucleic acid is insufficient in amount and/or of poor quality. At present a LB and a TB are rarely performed simultaneously before treatment and/or on tumor progression. This complementary/matched testing approach is still controversial but needs to be better evaluated to determine the true benefit to care of patients. This review provides an update on the complementarity of the LB and TB method for care of patients presenting with aNS-NSCLC.

Correlation between immunotherapy biomarker PD-L1 expression and genetic alteration in patients with non-small cell lung cancer

Programmed death-ligand 1 (PD-L1) has been widely used in immunotherapy evaluation of patients with non-small cell lung cancer (NSCLC). However, the effect is not particularly ideal, and the association between PD-L1 and genetic alterations requires more exploration. Here, we performed targeted next-generation sequencing and PD-L1 immunohistochemistry (IHC) testing for PD-L1 expression on both tumor cells (TCs) and tumor-infiltrating immune cells (ICs) in 1549 patients. Our studies showed that surgical method of resection was positively correlated with IC+, and a low tumor mutation burden (TMB) was negatively correlated with TC+. Furthermore, we found that EGFR was mutually exclusive with both ALK and STK11. In addition, the features between PD-L1 expression status and genomic alterations were characterized. These results suggest that clinical characteristics and molecular phenotypes are associated with PD-L1 expression signatures, which may provide novel insights for improving the efficiency of immune checkpoint inhibitors (ICIs) in immunotherapy.

Lack of correlation between MET and PD-L1 expression in non-small cell lung cancer revealed by comparative study of matched biopsies and surgical resection samples

INTRODUCTION

Both MET expression and the PD-L1 tumor proportion score (TPS) are companion diagnostics for treatment of advanced non-small cell lung carcinoma (aNSCLC) patients. We evaluated the rate of correlation between MET expression and the PD-L1 TPS in matched biopsies and surgically resected specimens from NSCLC patients.

PATIENTS AND METHODS

This retrospective analysis assessed the prevalence and correlation between MET expression (SP44 clone) and the PD-L1 TPS (22C3 clone) by immunohistochemistry together with molecular alterations determined by targeted next-generation sequencing in matched lung biopsy and surgically lung resected specimens from 70 patients with NSCLC.

RESULTS

The study found a significant correlation between the MET H-score in surgical samples and matched biopsies (P-value < 0.0001), as well as between the PD-L1 TPS in paired biopsies and surgical samples (P-value < 0.0001). However, there was no significant correlation between the MET H-score or expression subgroups and the PD-L1 TPS in both types of paired samples (P-value = 0.47, and P-value = 0.90). The MET H-score was significantly higher in adenocarcinoma compared to squamous cell carcinoma (P-value < 0.0001). A mutational analysis showed that the MET H-score was significantly higher in NSCLC cases with targetable molecular alterations (P-value = 0.0095), while no significant correlation was found for the PD-L1 TPS.

CONCLUSIONS

Our study found no significant correlation between PD-L1 and MET expression in samples from NSCLC patients, highlighting the importance of personalized treatment strategies based on individual expression profiles. These findings provide valuable insight into the development of effective immunotherapy and targeted therapy for NSCLC patients.

PD-1/PD-L1 inhibitors in treatment-naïve, advanced non-small cell lung cancer patients with < 1% PD-L1 expression: a meta-analysis of randomized controlled trials

BACKGROUND

PD-1/PD-L1 inhibitors prolong survival in treatment-naïve, locally advanced, and metastatic non-small cell lung cancer (NSCLC) with positive PD-L1 expression (> 1%/ > 50%). Recent evidence has suggested that tumors with < 1% PD-L1 expression may also be predictive of PD-1/PD-L1 inhibiting agents.

METHODS

Systematic review and meta-analysis were conducted of randomized controlled trials (RCTs) evaluating PD-1/PD-L1 inhibitors that have assessed tumors with < 1% PD-L1 expression (negative PD-L1 expression). PD-1/PD-L1 inhibitors-chemotherapy combinations (PC) were compared with histology-selected chemotherapy with respect to overall survival (OS) and progression-free survival (PFS).

RESULTS

Twelve RCTs comprising 5410 participants (PD-1/PD-L1 inhibitors-chemotherapy: 3051; chemotherapy: 2359) met the inclusion criteria. Tumors with PD-L1 expression < 1% were evident in 38.9% of the pooled study population. A significant OS [hazard ratio (HR) 0.71 95% confidence interval (CI) 0.63-0.80, p < 0.00001] and PFS [HR 0.65 95% CI 0.58-0.72, p < 0.00001] benefit of PC was evident in tumors with negative PD-L1 expression. PD-1/PD-L1 inhibitors-chemotherapy combinations were more likely to achieve an objective response than chemotherapy [odds ratio, 1.86; 95% CI, 1.46-2.38, p < 0.00001]. Histologic subtypes and diagnostic assays did not modify the OS and PFS treatment effects for PC compared to chemotherapy.

CONCLUSION

Tumors harboring < 1% PD-L1 expression are likely to benefit from PD-1/PD-L1 inhibitor-chemotherapy regimens in advanced NSCLC.

Expression and Prognostic Significance of c-Myc, ALK, ROS1, BRAF, and PD-L1 Among Patients With Non-Small Cell Lung Cancer

Background:

Non-small cell lung cancer (NSCLC) remains a leading cause of cancer death worldwide, for which better knowledge in molecular prognostic factors is needed to improve clinical outcome. This study aimed to investigate the clinical significance of c-Myc, ALK, ROS1, BRAF, and PD-L1 in NSCLC patients.

Methods:

Formalin-fixed paraffin-embedded tissue specimens were obtained from 124 NSCLC patients. Of these, 66 matched specimens of normal respiratory epithelial and tumor tissue from patients with stages I-III, who underwent surgical resection, and 58 NSCLC specimens from stage IV patients were recruited into this analysis. Immunohistochemistry staining along with semiquantitative criteria were used to evaluate the expression of the interested proteins.

Results:

Of the 66 patients with stages I-III, positive expression of c-Myc was detected in 12 specimens (18.2%) of NSCLC tissue, whereas none of the normal respiratory epithelial tissue was found to have c-Myc expression (P < .001). Of the 66 NSCLC patients, 28 (43.8%) had PD-L1-positive staining on 1%-49% tumor cells and 7 (10.9%) patients expressed PD-L1 in ⩾50% tumor cells. One (2.3%) adenocarcinoma patient was found to have ROS1 rearrangement. Patients with no expression of c-Myc and PD-L1 (co-negative expression) tended to have a better prognosis than other subgroups.

Conclusions:

NSCLC tissue significantly expressed more c-Myc and PD-L1, compared with the matched normal respiratory epithelium, emphasizing the important role of these key drivers in tumorigenesis. Therapeutic approach to precisely inhibit the targetable molecular pathways should be considered on an individual patient basis to improve survival outcome.

A novel multifunctional anti-PD-L1-CD16a-IL15 induces potent cancer cell killing in PD-L1-positive tumour cells

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Anti-PD-L1 single-domain antibodies were identified from hPD-L1-immunized camels.

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Three novel multifunctional antibodies, anti-PD-L1-CD16a, anti-PD-L1-IL15, and anti-PD-L1-CD16a-IL15, target PD-L1-positive cancer cells.

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Anti-PD-L1-IL15 and anti-PD-L1-CD16a-IL15, but not anti-PD-L1-CD16a, stimulate immune cell proliferation in vitro.

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The anti-PD-L1 antibodies can bind PD-L1-positive cells.

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Anti-PD-L1-CD16a-IL15 has the strongest antitumour activity, both in vitro and in vivo.

Cancer is the most acute disease and the leading cause of patient death worldwide. Both chemotherapy and molecular-based therapies play an important role in curing cancer. However, the median and overall survival of patients is poor. To date, immune therapies have changed the treatment methods for cancer patients. Programmed death ligand 1 (PD-L1, also known as B-H1, CD274) is a well-studied tumor antigen. PD-L1 is overexpressed in colon cancer, lung cancer, and so on and plays a vital role in cancer development. In this study, anti-PD-L1 single-domain antibodies were identified from recombinant human PD-L1 (rhPD-L1)-immunized llamas. Then, we generated a novel multifunctional anti-PD-L1-CD16a-IL15 antibody targeting PD-L1-positive tumor cells. Anti-PD-L1-CD16a-IL15 was constructed by linking the Interleukin-2 (IL-2) signal peptide, anti-PD-L1 single domain antibody (anti-PD-L1-VHH) and anti-cluster of differentiation 16a single domain antibody (anti-CD16a-VHH), and Interleukin-15/Interleukin-15 receptor alpha (IL15/IL-15Rα). This anti-PD-L1-CD16a-IL15 fusion protein can be expressed and purified from HEK-293F cells. In vitro, our data showed that the anti-PD-L1-CD16a-IL15 fusion protein can recruit T cells and drive natural killer cells (NK) with specific killing of PD-L1-overexpressing tumor cells. Furthermore, in the xenograft model, the anti-PD-L1-CD16a-IL15 fusion protein inhibited tumor growth with human peripheral blood mononuclear cells (PBMCs). These data suggested that the anti-PD-L1-CD16a-IL15 fusion protein has a latent function in antitumour activity, with better guidance for future cancer immunotherapy.

Which role for predictors of response to immune checkpoint inhibitors in hepatocellular carcinoma?

INTRODUCTION

Hepatocellular carcinoma (HCC) remains a frequently diagnosed malignancy worldwide, still representing an important cause of cancer-related death. Recent years have seen the emergence of novel systemic treatments for HCC patients, including immune checkpoint inhibitors (ICIs). Nonetheless, several questions regarding HCC immunotherapy remain unanswered, especially in terms of biochemical predictors of response.

AREAS COVERED

In the current paper, we will discuss available evidence regarding predictive biomarkers of response to HCC immunotherapy. A literature search was conducted in January 2022 of Pubmed/Medline, Cochrane library, and Scopus databases.

EXPERT OPINION

The identification of predictive biomarkers represents an unmet need in HCC patients receiving ICIs. The HCC medical community is called to further efforts aimed to elucidate the effective role of PD-L1 expression, TMB, MSI, gut microbiota, and other emerging biomarkers.

Current methods and emerging approaches for detection of programmed death ligand 1

Various tumor cells overexpress programmed death ligand 1 (PD-L1), a main immune checkpoint protein (ICP) embedded in the tumor cells membrane, to evade immune recognition through the interaction between PD-L1 and its receptor programmed death 1 (PD-1) which is from T-cells for maintaining immune tolerance. So inhibitors targeting the PD-1 or PD-L1 can block the PD-1/PD-L1 signaling pathway to restore the recognition activity of the immune system to tumor cells, which also have been utilized as a novel approach to improve the clinical therapeutic effect for cancer patients. Since not all cancer patients can respond to these inhibitors effectively, previous diagnosis of PD-L1 is significant to target the right treatments for cancer patients. This review pays attention to the PD-L1 detection and recent progress in the measurement of PD-L1 concentration, including various detection methods based on optical sensors as well as electrochemical assays. Apart from above those, we also focus on the prospects of PD-L1 detection in precision medicine.

Accounting for B-cell Behavior and Sampling Bias Predicts Anti-PD-L1 Response in Bladder Cancer

Cancer immunotherapy is predominantly based on T cell-centric approaches. At the same time, the adaptive immune response in the tumor environment also includes clonally produced immunoglobulins and clonal effector/memory B cells that participate in antigen-specific decisions through their interactions with T cells. Here, we investigated the role of infiltrating B cells in bladder cancer via patient dataset analysis of intratumoral immunoglobulin repertoires. We showed that the IgG1/IgA ratio is a prognostic indicator for several subtypes of bladder cancer and for the whole IMVigor210 anti-PD-L1 immunotherapy study cohort. A high IgG1/IgA ratio associated with the prominence of a cytotoxic gene signature, T-cell receptor signaling, and IL21-mediated signaling. Immunoglobulin repertoire analysis indicated that effector B-cell function, rather than clonally produced antibodies, was involved in antitumor responses. From the T-cell side, we normalized a cytotoxic signature against the extent of immune cell infiltration to neutralize the artificial sampling-based variability in immune gene expression. Resulting metrics reflected proportion of cytotoxic cells among tumor-infiltrating immune cells and improved prediction of anti-PD-L1 responses. At the same time, the IgG1/IgA ratio remained an independent prognostic factor. Integration of the B-cell, natural killer cell, and T-cell signatures allowed for the most accurate prediction of anti-PD-L1 therapy responses. On the basis of these findings, we developed a predictor called PRedIctive MolecUlar Signature (PRIMUS), which outperformed PD-L1 expression scores and known gene signatures. Overall, PRIMUS allows for reliable identification of responders among patients with muscle-invasive urothelial carcinoma, including the subcohort with the low-infiltrated "desert" tumor phenotype.

Artificial intelligence-assisted system for precision diagnosis of PD-L1 expression in non-small cell lung cancer

Standardized programmed death-ligand 1 (PD-L1) assessment in non-small cell lung cancer (NSCLC) is challenging, owing to inter-observer variability among pathologists and the use of different antibodies. There is a strong demand for the development of an artificial intelligence (AI) system to obtain high-precision scores of PD-L1 expression in clinical diagnostic scenarios. We developed an AI system using whole slide images (WSIs) of the 22c3 assay to automatically assess the tumor proportion score (TPS) of PD-L1 expression based on a deep learning (DL) model of tumor detection. Tests were performed to show the diagnostic ability of the AI system in the 22c3 assay to assist pathologists and the reliability of the application in the SP263 assay. A robust high-performance DL model for automated tumor detection was devised with an accuracy and specificity of 0.9326 and 0.9641, respectively, and a concrete TPS value was obtained after tumor cell segmentation. The TPS comparison test in the 22c3 assay showed strong consistency between the TPS calculated with the AI system and trained pathologists (R = 0.9429-0.9458). AI-assisted diagnosis test confirmed that the repeatability and efficiency of untrained pathologists could be improved using the AI system. The Ventana PD-L1 (SP263) assay showed high consistency in TPS calculations between the AI system and pathologists (R = 0.9787). In conclusion, a high-precision AI system is proposed for the automated TPS assessment of PD-L1 expression in the 22c3 and SP263 assays in NSCLC. Our study also indicates the benefits of using an AI-assisted system to improve diagnostic repeatability and efficiency for pathologists.

p40/PD-L1 and TTF1/PD-L1 Immunohistochemical Double Staining Contributes to Intraindividual Variability Associated With PD-L1 Staining Interpretation in Lung Cancer Samples

The important developments achieved in recent years with a consequent paradigm shift in the treatment of non-small cell lung cancer (NSCLC), including the latest immune checkpoint inhibitors, have led to an increasing need to optimize the scarce material usually available in the diagnosis of these tumors. In this sense, this study intends to evaluate the performance of double immunohistochemistry (IHC) in comparison to simple IHC for programmed death-ligand 1 (PD-L1) evaluation with 22C3 clone for selection to therapy with pembrolizumab. For that, 38 histologic samples of NSCLC small biopsies sent to our laboratory were selected. Double IHC were performed with the doublets TTF1/PD-L1 and p40/PD-L1, after all the usual diagnostic routine and molecular study was performed. The slides were interpreted by 2 independent pathologists and the results obtained were compared with each other and with the results obtained at diagnosis. A perfect agreement was observed when comparing the immunoexpression of TTF1 and p40 in double IHC in relation to single IHC. Although the agreement was substantial in the analysis of the positive/negative PD-L1 IHC (81.6% to 92.1%; κ=0.610 to 0.829) and in the analysis of the 50% cut-off (86.8% to 89.5%; κ=0.704 to 0.759), it fell short of the expected and desirable agreement for a biomarker such as PD-L1, since this result will have a major role in the institution of a treatment. In conclusion, this small series does not allow us to recommend this methodology for the evaluation of the PD-L1 biomarker in double staining IHC with the 22C3 clone for therapy selection.

Prognostic Value of Programmed Death Ligand-1 Expression in Solid Tumors Irrespective of Immunotherapy Exposure: A Systematic Review and Meta-Analysis

BACKGROUND

The programmed cell death-1/programmed cell death ligand-1 (PD-L1) pathway, which plays a crucial role in cancer immune surveillance, is the target of several approved immunotherapeutic agents and is used as a predictive biomarker in some solid tumors. However, its use as a prognostic marker (i.e., regardless of therapy used) is not established clearly with available data demonstrating inconsistent prognostic impact of PD-L1 expression in solid tumors.

METHODS

We conducted a systematic literature search of electronic databases and identified publications exploring the effect of PD-L1 expression on overall survival and/or disease-free survival. Hazard ratios were pooled in a meta-analysis using generic inverse-variance and random-effects modeling. We used the Deeks method to explore subgroup differences based on disease site, stage of disease, and method of PD-L1 quantification.

RESULTS

One hundred and eighty-six studies met the inclusion criteria. Programmed cell death ligand-1 expression was associated with worse overall survival (hazard ratio 1.33, 95% confidence interval 1.26-1.39; p < 0.001). There was significant heterogeneity between disease sites (subgroup p = 0.002) with pancreatic, hepatocellular, and genitourinary cancers associated with the highest magnitude of adverse outcomes. Programmed cell death ligand-1 was also associated with worse overall disease-free survival (hazard ratio 1.19, 95% confidence interval 1.09-1.30; p < 0.001). Stage of disease did not significantly affect the results (subgroup p = 0.52), nor did the method of quantification via immunohistochemistry or messenger RNA (subgroup p = 0.70).

CONCLUSIONS

High expression of PD-L1 is associated with worse survival in solid tumors albeit with significant heterogeneity among tumor types. The effect is consistent in early-stage and metastatic disease and is not sensitive to method of PD-L1 quantification. These data can provide additional information for the counseling of patients with cancer about prognosis.

Identification of Master Regulators Driving Disease Progression, Relapse, and Drug Resistance in Lung Adenocarcinoma

Backgrounds: Lung cancer is the leading cause of cancer related death worldwide. Current treatment strategies primarily involve surgery, chemotherapy, radiotherapy, targeted therapy, and immunotherapy, determined by TNM stages, histologic types, and genetic profiles. Plenty of studies have been trying to identify robust prognostic gene expression signatures. Even for high performance signatures, they usually have few shared genes. This is not totally unexpected, since a prognostic signature is associated with patient survival and may contain no upstream regulators. Identification of master regulators driving disease progression is a vital step to understand underlying molecular mechanisms and develop new treatments.

Methods: In this study, we have utilized a robust workflow to identify potential master regulators that drive poor prognosis in patients with lung adenocarcinoma. This workflow takes gene expression signatures that are associated with poor survival of early-stage lung adenocarcinoma, EGFR-TKI resistance, and responses to immune checkpoint inhibitors, respectively, and identifies recurrent master regulators from seven public gene expression datasets by a regulatory network-based approach.

Results: We have found that majority of the master regulators driving poor prognosis in early stage LUAD are cell-cycle related according to Gene Ontology annotation. However, they were demonstrated experimentally to promote a spectrum of processes such as tumor cell proliferation, invasion, metastasis, and drug resistance. Master regulators predicted from EGFR-TKI resistance signature and the EMT pathway signature are largely shared, which suggests that EMT pathway functions as a hub and interact with other pathways such as hypoxia, angiogenesis, TNF-α signaling, inflammation, TNF-β signaling, Wnt, and Notch signaling pathways. Master regulators that repress immunotherapy are enriched with MYC targets, E2F targets, oxidative phosphorylation, and mTOR signaling.

Conclusion: Our study uncovered possible mechanisms underlying recurrence, resistance to targeted therapy, and immunotherapy. The predicted master regulators may serve as potential therapeutic targets in patients with lung adenocarcinoma.

Predictive Biomarkers for Checkpoint Inhibitor-Based Immunotherapy in Hepatocellular Carcinoma: Where Do We Stand?

Hepatocellular carcinoma (HCC) remains the sixth most commonly diagnosed malignancy worldwide, still representing an important cause of cancer-related death. Over the next few years, novel systemic treatment options have emerged. Among these, immune checkpoint inhibitors (ICIs) have been widely evaluated and are under assessment, as monotherapy or in combination with other anticancer agents in treatment-naïve and previously treated patients. In particular, the approval of the PD-L1 inhibitor atezolizumab plus the antiangiogenic agent bevacizumab as front-line treatment for advanced HCC has led to the adoption of this combination in this setting, and the IMbrave 150 phase III trial has established a novel standard of care. However, several questions remain unanswered, including the identification of reliable predictors of response to ICIs in HCC patients. In the current paper, we will provide an updated overview of potentially useful predictive biomarkers of response to immunotherapy in advanced HCC. A literature search was conducted in September 2021 of Pubmed/Medline, Cochrane library and Scopus databases.

Evaluation of the programmed death-ligand 1 mRNA expression and immunopositivity and their correlation with survival outcomes in Indian lung cancer patients

The presence of membranous immunopositivity of programmed death-ligand 1 (PD-L1) in tumors serves as a key determinant of response to immune checkpoint inhibitors. However, there are very limited studies on the evaluation of the PD-L1 mRNA expression and immunopositivity and their correlation with therapeutic response and survival outcomes, especially in Indian lung cancer patients. In this prospective study, conducted between 2017 and 2020, we collected biopsies and surgically resected tumors from 173 lung cancer patients. PD-L1 immunopositivity and mRNA expression were determined by immunohistochemistry using SP263 assay and qRT-PCR, respectively. PD-L1 expression was correlated with various clinicopathological variables, response to therapy, and survival outcomes using appropriate statistical methods. The median age was 60 years (range 33-81 years) with the majority of patients being male (86.5%) and smokers (83%). Histologically, the majority of patients were non-small cell lung cancer (89.4%) and of squamous cell carcinoma histology (64.3%). PD-L1 immunopositivity in tumor cells (tumor proportion score (TPS) ≥ 1%) was detected in 37.6%, while high immunopositivity (TPS ≥ 50%) was detected in 16.8% of lung cancer patients. Almost 76% of lung cancer patients with PD-L1 TPS ≥ 50% belonged to PD-L1 mRNA high-expression group. PD-L1 mRNA expression and immunopositivity did not correlate with response to therapy and survival outcomes. We conclude that PD-L1 immunopositivity and mRNA expression do not seem to serve as a prognostic biomarker for lung cancer patients treated with chemotherapy. More prospective studies should be planned to evaluate the predictive and prognostic relevance of PD-L1 expression in Indian lung cancer patients being treated with immune checkpoint inhibitors.

The Adipokine Component in the Molecular Regulation of Cancer Cell Survival, Proliferation and Metastasis

A hormonal imbalance may disrupt the rigorously monitored cellular microenvironment by hampering the natural homeostatic mechanisms. The most common example of such hormonal glitch could be seen in obesity where the uprise in adipokine levels is in virtue of the expanding bulk of adipose tissue. Such aberrant endocrine signaling disrupts the regulation of cellular fate, rendering the cells to live in a tumor supportive microenvironment. Previously, it was believed that the adipokines support cancer proliferation and metastasis with no direct involvement in neoplastic transformations and tumorigenesis. However, the recent studies have reported discrete mechanisms that establish the direct involvement of adipokine signaling in tumorigenesis. Moreover, the individual adipokine profile of the patients has never been considered in the prognosis and staging of the disease. Hence, the present manuscript has focused on the reported extensive mechanisms that culminate the basis of poor prognosis and diminished survival rate in obese cancer patients.

Nuclear imaging-guided PD-L1 blockade therapy increases effectiveness of cancer immunotherapy

Objectives

Strategies to improve the responsiveness of programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) checkpoint blockade therapy remain an essential topic in cancer immunotherapy. In this study, we developed a new radiolabeled nanobody-based imaging probe ^99mTc-MY1523 targeting PD-L1 for the enhanced therapeutic efficacy of PD-L1 blockade immunotherapy by the guidance of ^99mTc-MY1523 SPECT/CT imaging.

Methods

The binding affinity and specificity of nanobody MY1523 were measured in vitro. MY1523 was radiolabeled with ^99mTc by a site-specific transpeptidation of Sortase-A, and the biodistribution and single photon emission CT (SPECT)/CT were performed in mice bearing different tumors. We used interferon-γ (IFN-γ) as an intervention means to establish animal models with different levels of PD-L1 expression, then investigated the ability of ^99mTc-MY1523 SPECT/CT for the in vivo non-invasive measurement of PD-L1 expression in tumors. Finally, the PD-L1 blockade immunotherapies guided by ^99mTc-MY1523 SPECT/CT were carried out in MC-38, A20, and 4T1 tumor-bearing mouse models, followed by the testing of tumor infiltration T cells.

Results

MY1523 exhibited a high binding affinity and specificity to PD-L1 and had no competitive binding with the therapeutic antibody. ^99mTc-MY1523 was prepared with high specific activity and radiochemical purity. It was found that tumor PD-L1 expression was dynamically upregulated by IFN-γ intervention in MC-38, A20, and 4T1 tumor-bearing mouse models, as indicated by ^99mTc-MY1523 SPECT/CT. The PD-L1 blockade therapy initiated during the therapeutic time window determined by ^99mTc-MY1523 SPECT/CT imaging significantly enhanced the therapeutic efficacy in all animal models, while the tumor growth was effectively suppressed, and the survival time of mice was evidently prolonged. A correlation between dynamically upregulated PD-L1 expression and improved PD-L1 blockade therapy effectiveness was revealed, and the markedly increased infiltration of effector T cells into tumors was verified after the imaging-guided therapy.

Conclusion

Our results demonstrated that ^99mTc-MY1523 SPECT/CT allowed a real-time, quantitative and dynamic mapping of PD-L1 expression in vivo, and the imaging-guided PD-L1 blockade immunotherapy significantly enhanced the therapeutic efficacy. This strategy merits translation into clinical practice for the better management of combination therapies with radiotherapy or chemotherapy.

PD-L1, TMB, and other potential predictors of response to immunotherapy for hepatocellular carcinoma: how can they assist drug clinical trials?

INTRODUCTION

Hepatocellular carcinoma (HCC) represents the sixth most commonly diagnosed malignancy worldwide, accounting for millions of deaths annually. Despite immune checkpoint inhibitors (ICIs) reported important results, only a minority of HCC patients benefit from these treatments, and the identification of predictive biomarkers of response still remains a highly unmet need.

AREAS COVERED

Herein, we provide a timely overview of available evidence on biochemical predictors of response to immunotherapy in advanced HCC patients; we speculate on how PD-L1, TMB, and other emerging biomarkers could assist drug clinical trials in the near future. A literature search was conducted in June 2021 using Pubmed/Medline, Cochrane library, and Scopus databases.

EXPERT OPINION

Reliable predictors of response to ICIs are of pivotal importance to allow a proper stratification and selection of HCC patients that could derive more benefit from immunotherapy. Well-designed, multicenter clinical trials specifically focused on predictive biomarkers are warranted in this setting, where most of evidence currently derives from retrospective, single-center studies with small sample size.

A Pilot Study of Whether the Cold-Heat Syndrome Type is Associated with Treatment Response and Immune Status in Patients with Non-Small Cell Lung Cancer

The cold-heat syndrome type (ZHENG) is one of the essential elements of syndrome differentiation in East Asian Medicine. This pilot study aimed to explore the characteristics of non-small cell lung cancer (NSCLC) patients treated with immune checkpoint inhibitors (ICIs) based on the cold-heat syndrome type. Twenty NSCLC patients treated with ICI monotherapy were included in the study and completed the cold-heat syndrome differentiation questionnaire. Demographic and clinical characteristics of the included patients were obtained through electronic medical records. Additionally, blood samples of 10 patients were analyzed with cytokine level and immune profiling. Patients were divided into two groups of cold type (n = 9) and non-cold type (n = 11), according to the cold symptoms questionnaire's cutoff point. No significant difference between the two groups was observed in clinical response to ICIs (p=0.668). Progression-free survival (PFS) seemed to be longer in patients with non-cold type than cold type (p=0.332). In patients with adenocarcinoma, the non-cold type showed longer PFS than the cold type (p=0.036). Also, there were more patients with PD-L1 negative in the cold type compared to the non-cold type (p=0.050). In immune profiling, the proportion of effector memory CD8 T-cells was higher in patients with cold type than with non-cold type (p=0.015), and the proportion of terminal effector CD8 T-cells was lower in patients with cold type than with non-cold type (p=0.005). This pilot study has shown the potential for differences in prognosis and immune status between patients with cold and non-cold types. Hopefully, it provides essential information and insight into NSCLC patients' characteristics from the perspective of syndrome differentiation. Further large-scale observational studies and intervention studies are required.

CTLA-4 Expression and Its Clinical Significance in Breast Cancer

Breast cancer is the leading cause of women's death among all cancers. The main reason associated with this is the development of metastasis and therapy-resistant breast carcinoma (BC), which pose the main challenge of oncology nowadays. Evidence suggest that these tumors seem to have inhibitory mechanisms that may favor their progression and surveillance. Cancer cells can evade antitumor T cell responses by expressing some immune inhibitory molecules such as the cytotoxic T-lymphocyte antigen-4 (CTLA-4), whose clinical meaning has emerged in the last few years and is poorly understood in the BC context. This systematic literature review aims at identifying studies on CTLA-4 expression in BC, and address what is known about its clinical meaning. A literature search was performed in PubMed and LILACS databases, using the MESH terms "breast cancer"; "CTLA-4 Antigen/antagonists and inhibitors"; and "Lymphocytes, Tumor-Infiltrating/immunology", published in the last 10 years. In total, 12 studies were included in this review. Systematic review used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Despite the small number of eligible studies, the literature reports some associations between CTLA-4 expression in the tumor microenvironment and worse BC outcomes, regardless of its molecular subtype. CTLA-4 expression in BC is a putative marker of clinical significance and a rationale therapeutic target in the emerging field of immunotherapy.

Challenges and Opportunities in the Statistical Analysis of Multiplex Immunofluorescence Data

Simple Summary

Immune modulation is considered a hallmark of cancer initiation and progression, and has offered promising opportunities for therapeutic manipulation. Multiplex immunofluorescence (mIF) technology has enabled the tumor immune microenvironment (TIME) to be studied at an increased scale, in terms of both the number of markers and the number of samples. Another benefit of mIF technology is the ability to measure not only the abundance but also the spatial location of multiple cells types within a tissue sample simultaneously, allowing for assessment of the co-localization of different types of immune markers. Thus, the use of mIF technologies have enable researchers to characterize patient, clinical, and tumor characteristics in the hope of identifying patients whom might benefit from immunotherapy treatments. In this review we outline some of the challenges and opportunities in the statistical analyses of mIF data to study the TIME.

Abstract

Immune modulation is considered a hallmark of cancer initiation and progression. The recent development of immunotherapies has ushered in a new era of cancer treatment. These therapeutics have led to revolutionary breakthroughs; however, the efficacy of immunotherapy has been modest and is often restricted to a subset of patients. Hence, identification of which cancer patients will benefit from immunotherapy is essential. Multiplex immunofluorescence (mIF) microscopy allows for the assessment and visualization of the tumor immune microenvironment (TIME). The data output following image and machine learning analyses for cell segmenting and phenotyping consists of the following information for each tumor sample: the number of positive cells for each marker and phenotype(s) of interest, number of total cells, percent of positive cells for each marker, and spatial locations for all measured cells. There are many challenges in the analysis of mIF data, including many tissue samples with zero positive cells or “zero-inflated” data, repeated measurements from multiple TMA cores or tissue slides per subject, and spatial analyses to determine the level of clustering and co-localization between the cell types in the TIME. In this review paper, we will discuss the challenges in the statistical analysis of mIF data and opportunities for further research.

PD-L1 expression and its clinicopathologic and genomic correlation in the non-small cell lung carcinoma patients: An Indian perspective

BACKGROUND

Immunotherapy with checkpoint inhibitor programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) antibodies targeting the cellular immune checkpoints is the present area of interest showing promising results in patients with advanced non-small cell lung cancer (NSCLC). As there is paucity of PD-L1 expression data from the Indian perspective, we studied the correlation of clinicopathologic profile and oncogenic driver mutations in these patients.

MATERIALS AND METHODS

Samples from 252 advanced NSCLCs patients were studied for PD-L1 expression through immunohistochemistry using rabbit anti-human PD-L1 monoclonal antibody (clone SP263) on Ventana BenchMark ULTRA autostainer. Simultaneously, genetic mutations were studied by next generation sequencing (for EGFR, ALK, ROS, MET, and BRAF). PD-L1 expression was analyzed for association with clinicopathologic features and various mutations.

RESULTS

PD-L1 positivity was seen in 134 patients (53.2 %). It was twice more prevalent in males than females. No significant correlation was observed between PD-L1 expression with age, gender, site of testing (primary vs. metastatic tumors), smoking status, tumor laterality, stage, or histologic type; however, there was significant difference among solid and acinar types of adenocarcinoma combined together vs. other adenocarcinoma subtypes (p = 0.013), and well and moderately differentiated vs. poorly differentiated tumors (p = 0.022). When types/extent of PD-L1 positivity (≥25 %) were compared with demographics, clinical, and pathologic variables, significant differences were observed across the tumor grades (high-grade vs. low-grade) (p = 0.009) and stages (p = 0.039). The PD-L1 expression failed to demonstrate any statistical significance with oncogenic drivers. High PD-L1 expression (TPS ≥ 50) was observed in 27.6 % patients, and it was more prevalent in female patients (32.4 %), aged ≥60 years (33.8 %), smokers (27.3 %), poorly differentiated (36.8 %) and stage IV tumors (28.2 %). Exon 19 deletion was more prevalent in PD-L1 negative tumors whereas exon 21 substitution (L858R) was seen more in PD-L1 positive tumors.

CONCLUSIONS

This is the largest Indian study demonstrating PD-L1 expression in NSCLC patients comparing with clinicopathologic and genomic parameters. PD-L1 expression was significantly associated with high-grade, solid, and acinar types of adenocarcinoma and advanced tumors. High PD-L1 expression was more prevalent in female patients, aged ≥60 years, smokers, and poorly differentiated and stage IV tumors (28.2 %). Exon 19 deletion was more in PD-L1 negative tumors whereas exon 21 substitution (L858R) was more in PD-L1 positive tumors. PD-L1 is a potential predictive marker stratifying patients who benefit from PD-1 pathway-targeted therapy.

PD-L1 in Cytological Samples: A Review and a Practical Approach

With a growing number of predictive biomarkers needed to manage patients with non-small cell lung cancer (NSCLC), there has been a paradigm shift in care and handling of diagnostic samples. Among the various testing methods, immunohistochemistry (IHC) is the most cost- effective and widely available. Furthermore, over the past decade immunotherapy has emerged as one of the most promising cancer treatments. In this scenario IHC is the most used testing method available for PDL-1/PD1 immunotherapy. Several monoclonal antibodies targeting programmed death 1 (PD-1)/programmed death ligand-1 (PD-L1) pathways have been integrated into standard-of-care treatments of a wide range of cancer types, once provided evidence of PD-L1 expression in tumor cells by immunohistochemistry (IHC). Since currently available PD-L1 assays have been developed on formalin-fixed paraffin embedded (FFPE) histological specimens, a growing body of research is being dedicated to confirm the feasibility of applying PDL-1 assays also to cytological samples. Albeit promising results have been reported, several important issues still need to be addressed. Among these are the type of cytological samples, pre-analytical issues, cyto-histological correlation, and inter-observer agreement. This review briefly summarizes the knowledge of the role of cytopathology in the analysis of PD-L1 by immunocytochemistry (ICC) and future directions of cytopathology in the immunotherapy setting.

Next-Generation Sequencing with Liquid Biopsies from Treatment-Naïve Non-Small Cell Lung Carcinoma Patients

Recently, the liquid biopsy (LB), a non-invasive and easy to repeat approach, has started to compete with the tissue biopsy (TB) for detection of targets for administration of therapeutic strategies for patients with advanced stages of lung cancer at tumor progression. A LB at diagnosis of late stage non-small cell lung carcinoma (NSCLC) is also being performed. It may be asked if a LB can be complementary (according to the clinical presentation or systematics) or even an alternative to a TB for treatment-naïve advanced NSCLC patients. Nucleic acid analysis with a TB by next-generation sequencing (NGS) is gradually replacing targeted sequencing methods for assessment of genomic alterations in lung cancer patients with tumor progression, but also at baseline. However, LB is still not often used in daily practice for NGS. This review addresses different aspects relating to the use of LB for NGS at diagnosis in advanced NSCLC, including its advantages and limitations.

Applications of single-cell and bulk RNA sequencing in onco-immunology

The rising interest for precise characterization of the tumour immune contexture has recently brought forward the high potential of RNA sequencing (RNA-seq) in identifying molecular mechanisms engaged in the response to immunotherapy. In this review, we provide an overview of the major principles of single-cell and conventional (bulk) RNA-seq applied to onco-immunology. We describe standard preprocessing and statistical analyses of data obtained from such techniques and highlight some computational challenges relative to the sequencing of individual cells. We notably provide examples of gene expression analyses such as differential expression analysis, dimensionality reduction, clustering and enrichment analysis. Additionally, we used public data sets to exemplify how deconvolution algorithms can identify and quantify multiple immune subpopulations from either bulk or single-cell RNA-seq. We give examples of machine and deep learning models used to predict patient outcomes and treatment effect from high-dimensional data. Finally, we balance the strengths and weaknesses of single-cell and bulk RNA-seq regarding their applications in the clinic.

Clinical sequencing to assess tumor mutational burden as a useful biomarker to immunotherapy in various solid tumors

Background:

Immune checkpoint inhibitors (ICIs) have become established as a new therapeutic paradigm in various solid cancers. Predictive biomarkers to ICIs have not yet been fully established. Tumor mutational burden (TMB) has been considered as a useful marker to indicate patients who benefit from ICIs.

Methods:

We performed next-generation sequencing, including TMB analysis, as a routine clinical practice in 501 patients with advanced gastrointestinal (GI), genitourinary (GU), or rare cancers. The TruSight^™ Oncology 500 assay from Illumina was used as a cancer panel.

Results:

In total, 11.6% (58/501) were identified with tumors with high TMB and MSI-high status was confirmed in seven out of 501 cases (1.4%). High TMB was observed in 11.6% of patients with various solid tumors, including: GU cancers (36.0%, 9/25), colorectal cancer (15.2%, 23/151), biliary tract cancer (14.6%, 7/48), melanoma (14.3%, 3/21), gastric cancer (11.2%, 13/116), hepatocellular carcinoma (8.3%, 1/12), other GI tract cancers (4.5%, 1/22), and sarcoma (1.7%, 1/60). The objective response rate (ORR) to ICIs was 75% (nine out of 12) in solid tumor patients with high TMB and 25% (30 out of 40) in those with non-high TMB. Patients with high TMB had better ORR to ICIs than those with non-high TMB (p = 0.004). Univariate analysis revealed that the status of PD-L1 expression and of TMB (high versus non-high) had significant association in response to ICIs. However, in multivariate analysis, the status of TMB (high versus non-high) was only significantly related to the response to ICIs (p = 0.036).

Conclusion:

In the present study, we analyzed the TMB using a cancer panel for various solid tumor patients in routine clinical practice and also demonstrated the usefulness of TMB to predict the efficacy for ICIs.

Anticipating metastasis through electrochemical immunosensing of tumor hypoxia biomarkers

Metastasis is responsible for about 90% of cancer-associated deaths. In the context of solid tumors, the low oxygen concentration in the tumor microenvironment (hypoxia) is one of the key factors contributing to metastasis. Tumor cells adapt to these conditions by overexpressing certain proteins such as programmed death ligand 1 (PD-L1) and hypoxia-inducible factor 1 alpha (HIF-1α). However, the determination of these tumor hypoxia markers that can be used to follow-up tumor progression and improve the efficiency of therapies has been scarcely addressed using electrochemical biosensors. In this work, we report the first electrochemical bioplatform for the determination of PD-L1 as well as the first one allowing its simultaneous determination with HIF-1α. The target proteins were captured and enzymatically labeled on magnetic microbeads and amperometric detection was undertaken on the surface of screen-printed dual carbon electrodes using the hydrogen peroxide/peroxidase/hydroquinone system. Sandwich immunoassays were implemented for both the HIF-1α and PD-L1 sensors and the analytical characteristics were evaluated providing LOD values of 86 and 279 pg mL^-1 for the amperometric determination of PD-L1 and HIF-1α standards, respectively. The developed electrochemical immunoplatforms are competitive versus the only electrochemical immunosensor reported for the determination of HIF-1α and the "gold standard" ELISA methodology for the single determination of both proteins in terms of assay time, compatibility with the simultaneous determination of both proteins making their use suitable for untrained users at the point of attention. The dual amperometric immunosensor was applied to the simultaneous determination of HIF-1α and PD-L1 in cancer cell lysates. The analyses lasted only 2 h and just 0.5 μg of the sample was required.

Biochemical predictors of response to immune checkpoint inhibitors in unresectable hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents the most commonly diagnosed liver cancer worldwide, and the overall survival of patients with unresectable disease is poor. In the last five years, immune checkpoint inhibitors (ICIs) have revolutionized the treatment scenario of several hematological and solid tumors, and these agents have been actively explored in unresectable HCC. Firstly, promising findings of phase I and II clinical studies reporting durable responses and a tolerable safety profile have led to the assessment of ICIs as single agents in phase III clinical studies; however, the latter have provided controversial results, and the activity of ICI monotherapy seems limited to a small subgroup of patients. Conversely, the IMbrave150 trial recently showed that, among patients with previously untreated unresectable HCC, treatment with atezolizumab plus bevacizumab resulted in significantly longer overall survival and progression-free survival compared to sorafenib monotherapy. In addition, the activity of several other ICIs is under investigation, as combination immunotherapy as well as combinations of immunotherapy with antiangiogenic agents. Nonetheless, there are currently no validated predictive biomarkers able to guide treatment choice in this setting, where the identification of specific predictors of response to ICIs represents a major challenge. In this review, we aim to provide a critical overview of recent evidence on biochemical predictors of response to ICIs in patients with unresectable HCC, especially focusing on PD-L1, TMB, MSI, and other emerging biomarkers.

The Importance of STK11/LKB1 Assessment in Non-Small Cell Lung Carcinomas

Despite the recent implementation of immunotherapy as a single treatment or in combination with chemotherapy for first-line treatment of advanced non-small cell lung cancer (NSCLC), many patients do not benefit from this regimen due to primary treatment resistance or toxicity. Consequently, there is an urgent need to develop efficient biomarkers that can select patients who will benefit from immunotherapy thereby providing the appropriate treatment and avoiding toxicity. One of the biomarkers recently described for the stratification of NSCLC patients undergoing immunotherapy are mutations in STK11/LKB1, which are often associated with a lack of response to immunotherapy in some patients. Therefore, the purpose of this review is to describe the different cellular mechanisms associated with STK11/LKB1 mutations, which may explain the lack of response to immunotherapy. Moreover the review addresses the co-occurrence of additional mutations that may influence the response to immunotherapy and the current clinical studies that have further explored STK11/LKB1 as a predictive biomarker. Additionally this work includes the opportunities and limitations to look for the STK11/LKB1 status in the therapeutic strategy for NSCLC patients.

Prospective evaluation of EBUS-TBNA specimens for programmed death-ligand 1 expression in non-small cell lung cancer patients: a pilot study

OBJECTIVE

EBUS-TBNA cytological sampling is routinely performed for pathological diagnosis, mediastinal staging, and molecular testing in lung cancer patients. EBUS-TBNA samples are not formally accepted for testing programmed death-ligand 1 (PD-L1) expression. The objective of the study was to compare the feasibility, reproducibility, and accuracy of PD-L1 expression assessment in cytological specimens and histological samples.

METHODS

We prospectively collected histological (transbronchial forceps biopsy) and cytological (EBUS-TBNA) samples from peribronchial neoplastic lesions during an endoscopic procedure at the same target lesion for the pathological diagnosis and molecular assessment of stage IV non-small cell lung cancer (NSCLC).

RESULTS

Fifteen patients underwent the procedure. Adequate cytological samples (at least 100 neoplastic cells) were obtained in 12 cases (92.3%). Assessment of PD-L1 expression was similar between histological and cytological samples (agreement rate = 92%). Sensitivity and diagnostic accuracy of EBUS-TBNA cytological specimens were 88.9% and 100%, respectively.

CONCLUSIONS

The evaluation of PD-L1 expression in EBUS-TBNA cytological specimens is feasible and presents good reproducibility when compared with routine histological samples. EBUS-TBNA cytological samples could be used for the assessment of PD-L1 expression in patients with NSCLC as a minimally invasive approach in stage IV NSCLC cancer patients.

PD-L1 Expression in 65 Conjunctival Melanomas and Its Association with Clinical Outcome

Conjunctival melanoma (CM) iss a rare and aggressive tumour that is increasing in frequency. The prognostic value of PD-L1 expression, alone or in combination with CD8 and PD-1 expression and the BRAF and NRAS status, has not been determined in CM to date. We evaluated the expression of PD-L1, CD8, PD-1 in CM and investigated whether there was an association between the expression of these markers and the BRAF and NRAS molecular profile as well as some clinico-pathological criteria. A total of sixty-five CM were assessed for PD-L1, PD-1, and CD8 expression by immunohistochemistry (IHC) and for BRAF and NRAS genomic alterations using molecular biology techniques and anti-BRAF and anti-NRAS antibodies. PD-L1 expression in tumour cells (TC) was very low or absent but detected in tumour-infiltrating immune cells (IC). A correlation was observed between the expression of PD-L1, CD8, and PD-1 in IC. No correlation between PD-L1 expression (in tumour and/or immune cells) and BRAF or NRAS mutations was observed. PD-L1 expression in IC correlated with a higher pTNM stage and PD-L1 expression in TC with worse disease-specific survival. PD-L1 expression is a potential prognostic biomarker that correlates with poor prognosis in CM patients.

The immune contexture and Immunoscore in cancer prognosis and therapeutic efficacy

The international American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) tumour-node-metastasis (TNM) staging system provides the current guidelines for the classification of cancer. However, among patients within the same stage, the clinical outcome can be very different. More recently, a novel definition of cancer has emerged, implicating at all stages a complex and dynamic interaction between tumour cells and the immune system. This has enabled the definition of the immune contexture, representing the pre-existing immune parameters associated with patient survival. Even so, the role of distinct immune cell types in modulating cancer progression is increasingly emerging. An immune-based assay named the 'Immunoscore' was defined to quantify the in situ T cell infiltrate and was demonstrated to be superior to the AJCC/UICC TNM classification for patients with colorectal cancer. This Review provides a broad overview of the main immune parameters positively or negatively shaping cancer development, including the Immunoscore, and their prognostic and predictive value. The importance of the immune system in cancer control is demonstrated by the requirement for a pre-existing intratumour adaptive immune response for effective immunotherapies, such as checkpoint inhibitors. Finally, we discuss how the combination of multiple immune parameters, rather than individual ones, might increase prognostic and/or predictive power.

Novel PD-L1 mAb HC16 reveals upregulation of PD-L1 in BAC subtype

Programmed death-ligand 1 (PD-L1) is an inhibitory transmembrane protein that can prevent autoimmune response. Upregulated PD-L1 serves as a predictive biomarker for patients who may respond well to immune checkpoint therapies. However, variable associations of PD-L1 level with prognoses have been reported. In this study, a short peptide sequence corresponding to PD-L1 amino acids 172-187 (from the extracellular Ig-like C-type domain, and with high predicted antigenicity and hydrophilicity) was used to generate a monoclonal antibody (mAb). The resultant PD-L1 mAb, clone HC16, was examined for binding specificity and reactivity in cancer cell-lines, as assessed by immunocytochemical, immunoblotting, and co-immunoprecipitation. The potential diagnostic and clinical applicability of clone HC16 was further tested using malignant tissue arrays derived from various cancer types analyzed with an automated immunohistochemical (IHC) staining platform. Additionally, tumor samples from patients diagnosed with non-small cell lung cancer (NSCLC) were analyzed by western blotting. Clone HC16 showed obvious staining activity in lung and breast cancer tissues. Interestingly, we observed that PD-L1 level was negatively associated with clinical stage in NSCLC. Strong PD-L1 expression tended to be found in patients diagnosed with bronchioloalveolar carcinoma (BAC). These results demonstrate that clone HC16 harbors good target specificity and is suitable for further development in diagnostic tools to assess PD-L1 expression in human tissues. In addition, our findings also suggest a role for PD-L1 in a non-invasive subtype of lung cancer.

A Novel Bispecific Antibody with PD-L1-assisted OX40 Activation for Cancer Treatment

Immunotherapy using OX40 agonist antibodies shows great preclinical efficacy in mouse tumor models. But in a clinical setting, OX40 agonist antibody alone or in combination with checkpoint blockade exhibits only modest efficacy due to lack of sufficient activation. We hypothesized that the limited antitumor activity in patients may due to insufficient clustering of OX40 antibody in the tumor. To test this hypothesis, we generated a tetravalent programmed death ligand-1 (PD-L1)/OX40 BsAb by fusing two PD-L1 VHH fragments to the C-terminus of a nonblocking agonistic anti-OX40 antibody. The resulting BsAb had intact function of each parental antibody, including efficiently blocking PD1/PD-L1 interaction and inducing OX40 activation. In addition, this BsAb showed significantly enhanced potency in activation of OX40-expressing T cells when PD-L1-expressing tumor cells or dendrite cells were present, through PD-L1-mediated cross-linking of OX40. Moreover, the BsAb exhibited superior antitumor activities over the parental monospecific antibodies alone or in combination in multiple in vivo tumor models. These results demonstrated a great potential for further clinical development of the potent immunostimulatory PD-L1/OX40 bispecific antibody.

Tissue Immune Profile: A Tool to Predict Response to Neoadjuvant Therapy in Triple Negative Breast Cancer

Pathological complete response (pCR) after neoadjuvant chemotherapy (NACT) can predict better survival outcomes in patients with early triple negative breast cancer (TNBC). Tumor infiltrating lymphocytes (TILs), Programmed Death-Ligand 1 (PD-L1), and Cluster of Differentiation 73 (CD73) are immune-related biomarkers that can be evaluated in the tumor microenvironment. We investigated if the contemporary expression of these biomarkers combined in a tissue immune profile (TIP) can predict pCR better than single biomarkers in TNBC. Tumor infiltrating lymphocytes (TILs), CD73 expression by cancer cells (CC), and PD-L1 expression by immune cells (IC) were evaluated on pre-NACT biopsies. We defined TIP positive (TIP+) as the simultaneous presence of TILS ≥ 50%, PD-L1 ≥ 1%, and CD73 ≤ 40%. To consider the effects of all significant variables on the pCR, multivariate analysis was performed. Akaike information criterion (AIC) and Bayesian information criterion (BIC) were used for model selection. We retrospectively analyzed 60 biopsies from patients with TNBC who received standard NACT. Pathological complete response was achieved in 23 patients (38.0%). Twelve (20.0%) cases resulted to be TIP+. The pCR rate was significantly different between TIP+ (91.7%) and TIP- (25.0%) (p < 0.0001). Using a multivariate analysis, TIP was confirmed as an independent predictive factor of pCR (OR 49.7 (6.30-392.4), p < 0.0001). Finally, we compared the efficacy of TIP versus each single biomarker in predicting pCR by AIC and BIC. The combined immune profile is more accurate in predicting pCR (AIC 68.3; BIC 74.5) as compared to single biomarkers. The association between TIP+ and pCR can be proposed as a novel link between immune background and response to chemotherapy in TNBC, highlighting the need to consider an immunological patients' profile rather than single biomarkers.

Elevated Neutrophil-to-Lymphocyte Ratio Is Associated With Poor Outcomes for Melanoma Patients Treated With PD-1 Inhibitor or Chemotherapy in a Chinese Population

Background: Previous studies have suggested that an elevated pre-treatment neutrophil-to-lymphocyte ratio (NLR) is associated with worse outcomes in patients with a variety of cancers. The purpose of this retrospective analysis is to investigate the prognostic value of the NLR in a Chinese melanoma population.

Methods: Melanoma patients were divided into two groups based on pre-treatment NLR values (≥3 vs. <3). Cox proportional hazard regression analysis and the Kaplan-Meier method were employed to study the prognostic role of the NLR for overall survival (OS) and progression-free survival (PFS).

Results: A total of 159 melanoma patients were included in this study, including 40 patients treated with PD-1 inhibitor and 119 patients treated with chemotherapy. In the PD-1 inhibitor group, the median OS was 18.0 months in the low NLR subgroup and 5.6 months in the high NLR subgroup; the median PFS was 7.0 and 2.2 months, respectively. In chemotherapy group, the median OS was 23.0 months in the low NLR group and 8.0 months in the high NLR group, and the median PFS was 9.0 and 4.0 months, respectively. Multivariate analysis showed that the NLR was significantly associated with OS and PFS in melanoma patients treated with either PD-1 inhibitor immunotherapy or chemotherapy.

Conclusion: In the Chinese population, an elevated NLR was closely related to worse survival in patients with melanoma treated with either PD-1 inhibitor monotherapy or chemotherapy.

Evaluation of PD-L1, PD-L2, PD-1 and cytotoxic immune response in oral lichen planus

OBJECTIVE

To investigate the expression of programmed death-ligands 1 and 2 (PD-L1, PD-L2), programmed death-1 (PD-1), CD8 and granzyme B (GrB), as well as its correlation with the severity of oral lichen planus (OLP).

MATERIALS AND METHODS

In a collaborative study, 33 cases of OLP were evaluated according to the latest criteria proposed by the American Academy of Oral and Maxillofacial Pathology (AAOMP/2016) and were submitted to immunohistochemistry. Positivity was measured semiquantitatively (PD-L1, PD-L2) and quantitatively (PD-1, CD8, GrB). The severity of OLP was assessed according to clinical subtype, symptomatology and response to corticosteroid therapy.

RESULTS

Most OLPs were considered to be negative for PD-L1 (66.6%), but high expression of PD-L2 (96.9%) by keratinocytes and immunoinflammatory cells was observed. PD-1⁺ cell density/mm² was reduced compared to CD8⁺ cells. A low cytotoxic immune response (CD8:GrB ratio) was also demonstrated. Interestingly, there were fewer GrB⁺ cells in the intraepithelial region in reticular OLP compared to erosive/bullous OLP.

CONCLUSIONS

PD-L1/PD-1 pathways appear to be compromised in OLP due to low PD-L1 expression in most samples. In contrast, PD-L2 overexpression associated with a possible regulation of the cytotoxic immune response suggests an immune tolerance that may contribute to the chronic profile of OLP.

PD-L1 as a prognostic biomarker in surgically resectable non-small cell lung cancer: a meta-analysis

Background

PD-L1 tumor expression has been associated with poor prognosis in a variety of solid tumors, including lung cancer, and represents a validated target for immune checkpoint inhibition in advanced malignances. It remains unknown, however, if PD-L1 can be used to predict survival in early stage, surgically treated cancers. This meta-analysis compares PD-L1 tumor expression and long term survival after surgical resection in early non-small cell lung cancer (NSCLC).

Methods

PubMed was searched to identify eligible studies that compared survival of surgically resected stage I–III NSCLC patients according to PD-L1 tumor expression. Included studies were grouped according to measurement criteria of PD-L1 expression: 1%, 5%, 50% cutoffs or H-score. Meta-analysis was performed using a linear mixed-effects model to determine overall survival (OS). I² was used as a measure of heterogeneity.

Results

There were 40 eligible studies, including 10,380 patients. Regardless of cut-off used, higher PD-L1 tumor expression was associated with worse OS [hazard ratio (HR)_1%: 1.59, 95% confidence interval (CI), 1.17–2.17; HR_5%: 1.44, 95% CI, 1.03–2.00; HR_50%: 1.52, 95% CI, 1.02–2.25, HR_H-score: 1.34, 95% CI, 1.04–1.73]. Study heterogeneity was low and not statistically significant under all PD-L1 cutoffs.

Conclusions

PD-L1 expression is consistently associated with worse survival, regardless of how it is quantified. In addition to acting as a prognostic biomarker, PD-L1 may also be used in future as a predictive biomarker for patients most likely to benefit from adjuvant immunotherapy.

Prognostic Value of Immune Environment Analysis in Small Bowel Adenocarcinomas with Verified Mutational Landscape and Predisposing Conditions

Background: Small bowel adenocarcinoma (SBA) is a rare yet insidious cancer with poor survival. The abundance of tumour-infiltrating lymphocytes is associated with improved survival, but the role of the programmed death-1/programmed death ligand-1 (PD-1/PD-L1) pathway in tumour escape is controversial. We evaluated immune cell infiltration, PD1/PD-L1 expression and their prognostic value in a series of SBAs with previously verified predisposing conditions and exome-wide somatic mutation characterization. Methods: Formalin-fixed paraffin-embedded tissue sections stained for CD3, CD8, PD-L1 and PD-1 were analysed from 94 SBAs. An immune cell score (ICS) was formed from the amount of the CD3 and CD8 positive lymphocytes from the tumour centre and invasive margin. The PD-L1 and PD-1 positive immune cells (ICs) and ICS were combined into a variable called Immunoprofile. Results: High ICS, PD-L1^IC and PD-1, individually and combined as Immunoprofile, were prognostic for better patient outcome. Sixty-five (69%) SBAs expressed ≥1% positive PD-L1^IC. A high tumour mutation burden was common (19%) and associated with immune markers. Immunoprofile, adjusted for TNM stage, mismatch repair status, tumour location, sex and age were independent prognostic markers for disease-specific and overall survival. Conclusions: Analysing tumoral immune contexture provides prognostic information in SBA. Combining ICS, PD-1 and PD-L1^IC as Immunoprofile enhanced the prognostic performance.

mRNA Display Discovery of a Novel Programmed Death Ligand 1 (PD-L1) Binding Peptide (a Peptide Ligand for PD-L1)

Programmed death ligand 1 (PD-L1) is a critical immune checkpoint ligand whose overexpression on tumor cells provides a mechanism of escape from immune surveillance. The interaction between PD-L1 and PD-1 on T cell lymphocytes suppresses both T cell activation and effector function and is engaged by cancers to dampen antitumor immunity. Here, we used mRNA display to engineer an 18-residue linear peptide that binds to human PD-L1. This peptide, which we term SPAM (signal peptide-based affinity maturated ligand), is nonhomologous to known PD-L1 binding peptides and mAbs, with dissociation constants (K_D) of 119 and 67 nM for unglycosylated and glycosylated human PD-L1, respectively. The SPAM peptide is highly selective for human PD-L1 and shows no significant binding to either mouse PD-L1 or human PD-L2. Competition binding assays indicate that the SPAM peptide binding site overlaps with the binding site of PD-1 as well as therapeutic anti-PD-L1 antibodies. Taken together, these results suggest that the SPAM peptide specifically binds to human PD-L1 and could potentially serve as a PD-L1 affinity agent and PD-L1/PD-1 pathway modulator.