Comparison of Biomarker Modalities for Predicting Response to PD-1/PD-L1 Checkpoint Blockade: A Systematic Review and Meta-analysis

Mass Spectrometry-Based Multivariate Proteomic Tests for Prediction of Outcomes on Immune Checkpoint Blockade Therapy: The Modern Analytical Approach

The remarkable success of immune checkpoint inhibitors (ICIs) has given hope of cure for some patients with advanced cancer; however, the fraction of responding patients is 15-35%, depending on tumor type, and the proportion of durable responses is even smaller. Identification of biomarkers with strong predictive potential remains a priority. Until now most of the efforts were focused on biomarkers associated with the assumed mechanism of action of ICIs, such as levels of expression of programmed death-ligand 1 (PD-L1) and mutation load in tumor tissue, as a proxy of immunogenicity; however, their performance is unsatisfactory. Several assays designed to capture the complexity of the disease by measuring the immune response in tumor microenvironment show promise but still need validation in independent studies. The circulating proteome contains an additional layer of information characterizing tumor-host interactions that can be integrated into multivariate tests using modern machine learning techniques. Here we describe several validated serum-based proteomic tests and their utility in the context of ICIs. We discuss test performances, demonstrate their independence from currently used biomarkers, and discuss various aspects of associated biological mechanisms. We propose that serum-based multivariate proteomic tests add a missing piece to the puzzle of predicting benefit from ICIs.

Genome-Wide Profiling of Human Papillomavirus DNA Integration into Human Genome and Its Influence on PD-L1 Expression in Chinese Uygur Cervical Cancer Women

Background

The Uygur is the fifth most populous ethnic group in China. Compared to other Chinese population, cervical cancer in them had high incidence, and HPV infection also was particular. Their HPV integration situation has never been reported. We aimed to investigate the integration situation of 20 subtypes of HPV gene into host cell genome in Chinese Uygur cervical cancer patients; meanwhile, we explored the influence of gene integration on PD-L1 expression.

Methods

40 frozen Chinese Uygur cervical cancer specimens with positive HPV infection were obtained from the cancer prevention and treatment institute of Tumor Hospital Affiliated to Xinjiang Medical University. The integration situation of HPV gene into host cell genome was detected by Agilent SureSelect™ Target Enrichment Chip and Next-Generation Sequencing. The related genes were analyzed by GO functional annotation and KEGG pathway enrichment. The expression levels of PD-L1 in cancer cells were tested by immunohistochemical assay (IHC). Meanwhile, the relationship between PD-L1 levels in cancer cells and gene integration were analyzed.

Results

The HPV multiple infection rate by HIVID was as high as 92.5%, much higher than 35.0% by the commercial kit (P < 0.05). There were 13423 integration events in 40 specimens, involving 6867 human genes. These integration events were distributed on all human chromosomes, and chromosome 19 had the excessive concentration phenomenon of integration events. There were some integration hotspots in human genome such as PPP1R37, HECW2, EMBP1, ANKRD50, SPTBN4, LINC00895, LYRM4-AS1, LINC00374, RBFOX1, CSMD1, CDH13, and KLHL4. Insertion breakpoints can be found in all gene regions of the HPV genome. The actual observation of the integration times of E1 and E6 was much higher than the expected value, while the actual observation times of E5 were much lower than the expected value. The result of GO functional analysis showed that binding molecular function and cellular process biological process were the main ways to influence the cell biological behavior of HPV gene integration. The enrichment pathway analysis of KEGG showed that pathways in cancer were the most important enrichment pathways involved in the genomic integration of HPV. The positive PD-L1 rate was 62.5%. Logistic regression analysis showed that 9p24.1 existing integration sites and the number of all gene integration were risk factors for PD-L1 expression (odds ratio 17.313 and 1.012; 95% confidence interval 1.691-177.213 and 1.001-1.023). Conclusions and Relevance. Most high-frequency sites of HPV integration in Chinese Uygur cervical cancer are related to cancer progression, and the gene integration hotspots may be potential HPV carcinogenic targets. The problem of multiple HPV infection in Chinese Uygur cervical cancer patients should be paid attention. L1 and E6 genes are inapposite as the target gene of commercial HPV type detection kit, because of high-frequency breakpoints in these genes. The gene integration especially the integration existing on 9p24.1 could affect the expression level of PD-L1.

Multiplex immunohistochemistry/immunofluorescence (mIHC/IF) for PD-L1 testing in triple-negative breast cancer: a translational assay compared with conventional IHC

BACKGROUND

Programmed death-ligand 1 (PD-L1) monoclonal antibody therapy has recently gained approval for treating metastatic triple-negative breast cancer (TNBC) -, in particular in the PD-L1⁺ patient subgroup of the recent IMpassion130 trial. The SP142 PD-L1 antibody clone was used as a predictive assay in this trial, but this clone was found to be an outlier in previous harmonisation studies in lung cancer.

AIMS

To address the comparability of PD-L1 clones in TNBC, we evaluated the concordance between conventional immunohistochemistry (IHC) and multiplex immunohistochemistry/immunofluorescence (mIHC/IF) that allowed simultaneous quantification of three different PD-L1 antibodies (22C3, SP142 and SP263).

METHODS

Our cohort comprised 25 TNBC cases, 12 non-small-cell lung carcinomas and 8 other cancers. EpCAM labelling was used to distinguish tumour cells from immune cells.

RESULTS

Moderate-to-strong correlations in PD-L1 positivity were found between results obtained through mIHC/IF and IHC. Individual concordance rates in the study ranged from 67% to 100%, with Spearman's rank correlation coefficient values up to 0.88.

CONCLUSIONS

mIHC/IF represents a promising tool in the era of cancer immunotherapy, as it can simultaneously detect and quantify PD-L1 labelling with multiple antibody clones, and allow accurate evaluation of tumour and immune cells. Clinicians and pathologists require this information to predict patient response to anti-PD-1/PD-L1 therapy. The adoption of this assay may represent a significant advance in the management of therapeutically challenging cancers. Further analysis and assay harmonisation are essential for translation to a routine diagnostic setting.

Digital image analysis of multiplex fluorescence IHC in colorectal cancer recognizes the prognostic value of CDX2 and its negative correlation with SOX2

Flourescence-based multiplex immunohistochemistry (mIHC) combined with multispectral imaging and digital image analysis (DIA) is a quantitative high-resolution method for determination of protein expression in tissue. We applied this method for five biomarkers (CDX2, SOX2, SOX9, E-cadherin, and β-catenin) using tissue microarrays of a Norwegian unselected series of primary colorectal cancer. The data were compared with previously obtained chromogenic IHC data of the same tissue cores, visually assessed by the Allred method. We found comparable results between the methods, although confirmed that DIA offered improved resolution to differentiate cases with high and low protein expression. However, we experienced inherent challenges with digital image analysis of membrane staining, which was better assessed visually. DIA and mIHC enabled quantitative analysis of biomarker coexpression on the same tissue section at the single-cell level, revealing a strong negative correlation between the differentiation markers CDX2 and SOX2. Both methods confirmed known prognostic associations for CDX2, but DIA improved data visualization and detection of clinicopathological and biological associations. In summary, mIHC combined with DIA is an efficient and reliable method to evaluate protein expression in tissue, here shown to recapitulate and improve detection of known clinicopathological and survival associations for the emerging biomarker CDX2, and is therefore a candidate approach to standardize CDX2 detection in pathology laboratories.

Nivolumab plus Carboplatin and Paclitaxel as the First-line Therapy for Advanced Squamous Cell Carcinoma of the Lung with Strong Programmed Death-ligand 1 Expression: A Case Report

An 80-year-old male patient was diagnosed to have squamous cell carcinoma of the lung which had a high level of programmed death-ligand 1 (PD-L1) expression. He was prescribed with intravenously administered nivolumab combined with carboplatin and paclitaxel as the first-line therapy. A rapid remission was achieved with nearly total necrosis and cavitation of the original tumor. However, the successful treatment result was accompanied with pneumonitis most likely as an adverse effect of nivolumab. After discontinuation of nivolumab and starting prednisolone treatment, the pneumonitis was soon brought under control. During the treatment course, temporary exacerbation of the disease status led to an interesting differential diagnosis between hyperprogression and pseudoprogression. Tremendous efficacy of combination immunochemotherapy as the first-line treatment for squamous non-small cell lung cancer (NSCLC) with highly expressed PD-L1 has been well demonstrated in this case.

Immune Checkpoints as Promising Targets for the Treatment of Idiopathic Pulmonary Fibrosis?

Idiopathic pulmonary fibrosis is a rare, progressive and fatal lung disease which affects approximately 5 million persons worldwide. Although pirfenidone and/or nintedanib treatment improves patients’ wellbeing, the prognosis of IPF remains poor with 5-year mortality rates still ranging from 70 to 80%. The promise of the anti-cancer agent nintedanib in IPF, in combination with the recent notion that IPF shares several pathogenic pathways with cancer, raised hope that immune checkpoint inhibitors, the novel revolutionary anticancer agents, could also be the eagerly awaited ground-breaking and unconventional novel treatment modality limiting IPF-related morbidity/mortality. In the current review, we analyse the available literature on immune checkpoint proteins in IPF to explore whether immune checkpoint inhibition may be as promising in IPF as it is in cancer. We conclude that despite several promising papers showing that inhibiting specific immune checkpoint proteins limits pulmonary fibrosis, overall the data seem to argue against a general role of immune checkpoint inhibition in IPF and suggest that only PD-1/PD-L1 inhibition may be beneficial.

Plasma Biomarkers and Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer: New Tools for Better Patient Selection?

Immune checkpoint inhibitors (ICIs) have transformed the treatment landscape for patients with non-small cell lung cancer (NSCLC). Although some patients can experience important response rates and improved survival, many others do not benefit from ICIs developing hyper-progressive disease or immune-related adverse events. This underlines the need to select biomarkers for ICIs use in order to better select patients. There is currently no universally validated robust biomarker for daily use of ICIs. Programmed death-ligand 1 (PD-L1) or tumor mutational burden (TMB) are sometimes used but still have several limitations. Plasma biomarkers are a promising approach in ICI treatment. This review will describe the development of novel plasma biomarkers such as soluble proteins, circulating tumor DNA (ctDNA), blood TMB, and blood microbiome in NSCLC patients treated with ICIs and their potential use in predicting response and toxicity.

Immunopathologic Stratification of Colorectal Cancer for Checkpoint Blockade Immunotherapy

Mismatch-repair deficiency in solid tumors predicts their response to PD-1 blockade. Based on this principle, pembrolizumab is approved as standard of care for patients with unresectable or metastatic microsatellite instability-high (MSI-H) cancer. Despite this success, a large majority of metastatic colorectal cancer patients are not MSI-H and do not benefit from checkpoint blockade treatment. Predictive biomarkers to develop personalized medicines and guide clinical trials are needed for these patients. We, therefore, asked whether immunohistologic stratification of metastatic colorectal cancer based on primary tumor PD-L1 expression associated with the presence or absence of extracellular mucin defines a subset of metastatic colorectal cancer patients who exhibit a preexisting antitumor immune response and who could potentially benefit from the checkpoint blockade. To address this, we studied 26 advanced metastatic colorectal cancer patients treated with pembrolizumab (NCT01876511). To stratify patients, incorporation of histopathologic characteristics (percentage of extracellular mucin) and PD-L1 expression at the invasive front were used to generate a composite score, the CPM (composite PD-L1 and mucin) score, which discriminated patients who exhibited clinical benefit (complete, partial, or stable disease) from those patients with progressive disease. When validated in larger cohorts, the CPM score in combination with MSI testing may guide immunotherapy interventions for colorectal cancer patient treatment.