Biomarkers of response to PD-1/PD-L1 inhibition

Immunotherapy and predictive immunologic profile: the tip of the iceberg

The interplay between cancer and the immune system has been under investigation for more than a century. Immune checkpoint inhibitors have changed the outcome of several tumors; however, there is a significant percentage of patients presenting resistance to immunotherapy. Besides the action mechanism, it is essential to unravel this complex interplay between host immune system and tumorigenesis to determine an immune profile as a predictive factor to immune checkpoint blockade agents. Tumor expression of programmed death-ligand 1 (PD-L1), tumor mutational burden, or mismatch repair deficiency are recognized predictive biomarkers to immunotherapy but are insufficient to explain the response rates and heterogeneity across tumor sites. Therefore, it is crucial to explore the role of the tumor microenvironment in the diversity and clonality of tumor-infiltrating immune cells since different checkpoint molecules play an influential role in cytotoxic T cell activation. Moreover, cytokines, chemokines, and growth factors regulated by epigenetic factors play a complex part. Peripheral immune cells expressing PD-1/PD-L1 and the biologic roles of soluble immune checkpoint molecules are the subject of new lines of investigation. This article addresses some of the new molecules and mechanisms studied as possible predictive biomarkers to immunotherapy, linked with the concept of immune dynamics monitoring.

Targeting the Tumor Microenvironment for Improving Therapeutic Effectiveness in Cancer Immunotherapy: Focusing on Immune Checkpoint Inhibitors and Combination Therapies

Immune checkpoints play critical roles in the regulation of T-cell effector function, and the effectiveness of their inhibitors in cancer therapy has been established. Immune checkpoint inhibitors (ICIs) constitute a paradigm shift in cancer therapy in general and cancer immunotherapy in particular. Immunotherapy has been indicated to reinvigorate antitumor T-cell activity and dynamically modulate anticancer immune responses. However, despite the promising results in the use of immunotherapy in some cancers, numerous patients do not respond to ICIs without the existence of a clear predictive biomarker. Overall, immunotherapy involves a certain degree of uncertainty and complexity. Research on the exploration of cellular and molecular factors within the tumor microenvironment (TME) aims to identify possible mechanisms of immunotherapy resistance, as well as to develop novel combination strategies involving the specific targeting of the TME for cancer immunotherapy. The combination of this approach with other types of treatment, including immune checkpoint blockade therapy involving multiple agents, most of the responses and effects in cancer therapy could be significantly enhanced, but the appropriate combinations have yet to be established. Moreover, the in-depth exploration of complexity within the TME allows for the exploration of pathways of immune dysfunction. It may also aid in the identification of new therapeutic targets. This paper reviews recent advances in the improvement of therapeutic efficacy on the immune context of the TME and highlights its contribution to cancer immunotherapy.

Integration of radiotherapy with anti-PD-1 antibody for the treatment of intrahepatic or hilar cholangiocarcinoma: reflection from four cases

Cholangiocarcinoma (CCA) represents a clinically challenging disease with a dismal prognosis. A therapeutic plateau has been reached with traditional treatments. However, with immunotherapy advances in cancer therapy, integration of stereotactic body radiotherapy (SBRT) with anti-PD-1 antibody shows a synergistic effect and high clinical efficacy in many cancer types. This combination may represent a breakthrough in the treatment of this fatal malignancy. Here, we report four cases of refractory advanced intrahepatic or hilar cholangiocarcinoma that were successfully controlled with anti-PD-1 antibody following or concurrent with SBRT. Furthermore, one case was initially unresectable; however, following this novel combined therapy, it became operable. We discuss the challenges of developing predictive biomarkers for anti-PD-1 antibody responsiveness. We also consider the regulatory effect of SBRT on the tumor microenvironment and the potential advantages of this therapy combination for treatment of intrahepatic or hilar cholangiocarcinoma. These are important considerations and provide direction for future clinical trial designs.

Sequential filtering for clinically relevant variants as a method for clinical interpretation of whole exome sequencing findings in glioma

BACKGROUND

In the clinical setting, workflows for analyzing individual genomics data should be both comprehensive and convenient for clinical interpretation. In an effort for comprehensiveness and practicality, we attempted to create a clinical individual whole exome sequencing (WES) analysis workflow, allowing identification of genomic alterations and presentation of neurooncologically-relevant findings.

METHODS

The analysis workflow detects germline and somatic variants and presents: (1) germline variants, (2) somatic short variants, (3) tumor mutational burden (TMB), (4) microsatellite instability (MSI), (5) somatic copy number alterations (SCNA), (6) SCNA burden, (7) loss of heterozygosity, (8) genes with double-hit, (9) mutational signatures, and (10) pathway enrichment analyses. Using the workflow, 58 WES analyses from matched blood and tumor samples of 52 patients were analyzed: 47 primary and 11 recurrent diffuse gliomas.

RESULTS

The median mean read depths were 199.88 for tumor and 110.955 for normal samples. For germline variants, a median of 22 (14-33) variants per patient was reported. There was a median of 6 (0-590) reported somatic short variants per tumor. A median of 19 (0-94) broad SCNAs and a median of 6 (0-12) gene-level SCNAs were reported per tumor. The gene with the most frequent somatic short variants was TP53 (41.38%). The most frequent chromosome-/arm-level SCNA events were chr7 amplification, chr22q loss, and chr10 loss. TMB in primary gliomas were significantly lower than in recurrent tumors (p = 0.002). MSI incidence was low (6.9%).

CONCLUSIONS

We demonstrate that WES can be practically and efficiently utilized for clinical analysis of individual brain tumors. The results display that NOTATES produces clinically relevant results in a concise but exhaustive manner.

Immune classification of clear cell renal cell carcinoma

Since the outcome of treatments, particularly immunotherapeutic interventions, depends on the tumor immune micro-environment (TIM), several experimental and computational tools such as flow cytometry, immunohistochemistry, and digital cytometry have been developed and utilized to classify TIM variations. In this project, we identify immune pattern of clear cell renal cell carcinomas (ccRCC) by estimating the percentage of each immune cell type in 526 renal tumors using the new powerful technique of digital cytometry. The results, which are in agreement with the results of a large-scale mass cytometry analysis, show that the most frequent immune cell types in ccRCC tumors are CD8+ T-cells, macrophages, and CD4+ T-cells. Saliently, unsupervised clustering of ccRCC primary tumors based on their relative number of immune cells indicates the existence of four distinct groups of ccRCC tumors. Tumors in the first group consist of approximately the same numbers of macrophages and CD8+ T-cells and and a slightly smaller number of CD4+ T cells than CD8+ T cells, while tumors in the second group have a significantly high number of macrophages compared to any other immune cell type (P-value \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$<0.01$$\end{document}<0.01). The third group of ccRCC tumors have a significantly higher number of CD8+ T-cells than any other immune cell type (P-value \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$<0.01$$\end{document}<0.01), while tumors in the group 4 have approximately the same numbers of macrophages and CD4+ T-cells and a significantly smaller number of CD8+ T-cells than CD4+ T-cells (P-value \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$<0.01$$\end{document}<0.01). Moreover, there is a high positive correlation between the expression levels of IFNG and PDCD1 and the percentage of CD8+ T-cells, and higher stage and grade of tumors have a substantially higher percentage of CD8+ T-cells. Furthermore, the primary tumors of patients, who are tumor free at the last time of follow up, have a significantly higher percentage of mast cells (P-value \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$<0.01$$\end{document}<0.01) compared to the patients with tumors for all groups of tumors except group 3.

Immune classification of clear cell renal cell carcinoma

Since the outcome of treatments, particularly immunotherapeutic interventions, depends on the tumor immune micro-environment (TIM), several experimental and computational tools such as flow cytometry, immunohistochemistry, and digital cytometry have been developed and utilized to classify TIM variations. In this project, we identify immune pattern of clear cell renal cell carcinomas (ccRCC) by estimating the percentage of each immune cell type in 526 renal tumors using the new powerful technique of digital cytometry. The results, which are in agreement with the results of a large-scale mass cytometry analysis, show that the most frequent immune cell types in ccRCC tumors are CD8+ T-cells, macrophages, and CD4+ T-cells. Saliently, unsupervised clustering of ccRCC primary tumors based on their relative number of immune cells indicates the existence of four distinct groups of ccRCC tumors. Tumors in the first group consist of approximately the same numbers of macrophages and CD8+ T-cells and and a slightly smaller number of CD4+ T cells than CD8+ T cells, while tumors in the second group have a significantly high number of macrophages compared to any other immune cell type (P-value [Formula: see text]). The third group of ccRCC tumors have a significantly higher number of CD8+ T-cells than any other immune cell type (P-value [Formula: see text]), while tumors in the group 4 have approximately the same numbers of macrophages and CD4+ T-cells and a significantly smaller number of CD8+ T-cells than CD4+ T-cells (P-value [Formula: see text]). Moreover, there is a high positive correlation between the expression levels of IFNG and PDCD1 and the percentage of CD8+ T-cells, and higher stage and grade of tumors have a substantially higher percentage of CD8+ T-cells. Furthermore, the primary tumors of patients, who are tumor free at the last time of follow up, have a significantly higher percentage of mast cells (P-value [Formula: see text]) compared to the patients with tumors for all groups of tumors except group 3.

Tissue MicroRNA Expression as a Predictor of Response to Immunotherapy in NSCLC Patients

Introduction

Expression of PD-L1 protein on tumor cells, which is so far the only validated predictive factor for immunotherapy, is regulated by epigenetic and genetic factors. Among the most important ones that regulate gene expression are microRNAs.

Materials and Methods

The study included 60 patients with NSCLC who underwent first or second line immunotherapy with pembrolizumab or nivolumab. FFPE materials were collected before the start of immunotherapy. We examined relative expression of microRNAs (miR-141, miR-200a, miR-200b, miR-200c, miR-429, miR-508-3p, miR-1184, miR-1255a) and PD-L1 mRNA expression. Copy number variation (CNV) of PD-L1 gene by qPCR and FISH methods were assessed. Two single nucleotide polymorphisms (SNPs) in promoter region of PD-L1 gene (rs822335 and rs822336) were examined. Expression of PD-L1 protein on tumor cells was assessed by immunohistochemistry (IHC). The response rate to immunotherapy and progression free survival (PFS) measured in weeks and overall survival (OS) measured in months from the start of immunotherapy were evaluated.

Results

Response to immunotherapy was observed in nine patients (15%, including one complete response), disease stabilization in 22 patients (36.7%), and progression in 29 patients (48.3%). Significantly higher (p=0.015) expression of miR-200b and significantly lower (p=0.043) expression of miR-429 were observed in responders compared to patients who did not respond to immunotherapy. The median PFS in the whole group of patients was 16 weeks, and the median OS was 10.5 month. In univariate analysis, the median PFS was significantly higher in patients with high miR-200b expression (HR=0.4253, 95%CI: 0.1737–1.0417, p=0.05) and high miR-508 expression (HR=0.4401, 95%CI: 0.1903–1.0178, p=0.05) and with low expression of miR-429 (HR=0.1288, 95%CI: 0.01727–0.9606, p=0.0456) compared to patients with low and high expression of these molecules, respectively. The median OS was higher in patients with low expression of miR-429 (HR=0,6288, 95%CI: 0,3053–1,2949, p=0.06) compared with patients with high expression of this microRNA. In multivariate analysis, we found that patients with PD-L1 expression on ≥1% of tumor cells compared to patients without PD-L1 expression on cancer cells had a significantly lower risk of progression (HR=0.3857, 95%CI: 0.1612–0.9226, p=0.0323) and death (HR=0.377, 95%CI: 0.1636–0.8688, p=0.022).

Conclusion

The miR-200b and miR-429 molecules in tumor cells seem to have greatest impact on the effectiveness of immunotherapy in NSCLC patients.

Identification of a two-gene prognostic model associated with cytolytic activity for colon cancer

Background

Increasing evidence has shown that cytolytic activity (CYT) is a new immunotherapy biomarker that characterises the antitumour immune activity of cytotoxic T cells and macrophages. In this study, we established a prognostic model associated with CYT.

Methods

A prognostic model based on CYT-related genes was developed. Furthermore, aberrant expression of genes of the model in colon cancer (CC) was identified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC) assays. Next, the correlation between the model and T-cell infiltration in the CC microenvironment was analysed. The Tumour Immune Dysfunction and Exclusion (TIDE) algorithm and subclass mapping were used to predict clinical responses to immune checkpoint inhibitors.

Results

In total, 280 of the 1418 genes were differentially expressed based on CYT. A prognostic model (including HOXC8 and MS4A2) was developed based on CYT-related genes. The model was validated using the testing set, the whole set and a Gene Expression Omnibus (GEO) cohort (GSE41258). Gene set enrichment analysis (GSEA) and other analyses showed that the levels of immune infiltration and antitumour immune activation in low-risk-score tumours were greater than those in high-risk-score tumours. CC patients with a low-risk-score showed more promise in the response to anti-immune checkpoint therapy.

Conclusions

Overall, our model may precisely predict the overall survival of CC and reflect the strength of antitumour immune activity in the CC microenvironment. Furthermore, the model may be a predictive factor for the response to immunotherapy.

Lower Airway Dysbiosis Affects Lung Cancer Progression

In lung cancer, enrichment of the lower airway microbiota with oral commensals commonly occurs, and ex vivo models support that some of these bacteria can trigger host transcriptomic signatures associated with carcinogenesis. Here, we show that this lower airway dysbiotic signature was more prevalent in the stage IIIB-IV tumor-node-metastasis lung cancer group and is associated with poor prognosis, as shown by decreased survival among subjects with early-stage disease (I-IIIA) and worse tumor progression as measured by RECIST scores among subjects with stage IIIB-IV disease. In addition, this lower airway microbiota signature was associated with upregulation of the IL17, PI3K, MAPK, and ERK pathways in airway transcriptome, and we identified Veillonella parvula as the most abundant taxon driving this association. In a KP lung cancer model, lower airway dysbiosis with V. parvula led to decreased survival, increased tumor burden, IL17 inflammatory phenotype, and activation of checkpoint inhibitor markers. SIGNIFICANCE: Multiple lines of investigation have shown that the gut microbiota affects host immune response to immunotherapy in cancer. Here, we support that the local airway microbiota modulates the host immune tone in lung cancer, affecting tumor progression and prognosis.See related commentary by Zitvogel and Kroemer, p. 224.This article is highlighted in the In This Issue feature, p. 211.

Predictive Potential of PD-L1, TYMS, and DCC Expressions in Treatment Outcome of Colorectal Carcinoma

Colorectal carcinoma (CRC) is a malignancy of epithelial origin in the large bowel. The elucidation of the biological functions of programmed cell death ligand-1 (PD-L1), thymidylate synthase (TYMS), and deleted in colorectal cancer (DCC) biomarkers including their roles in the pathophysiology of CRC - has led to their applications in diagnostic and chemo-pharmaceutics. We investigated whether PD-L1, TYMS, and DCC protein expression in CRC tumors are predictive biomarkers of treatment outcome for CRC patients. The expressions of PD-L1, TYMS, and DCC were evaluated by immunohistochemistry (IHC) in 91 paraffin-embedded samples from patients who underwent colectomy procedure in Hospital Serdang, Selangor, Malaysia. There was high expression of DCC in most cases: 84.6% (77/91). PD-L1 showed low expression in 93.4% (86/91) of cases and high expression in 6.6% (5/91) of cases. Low and high expressions of TYMS were detected in 53.8% (49/91) and 46.2% (42/91) of the CRC cases, respectively. There was a significant association between the TYMS expression and gender (P < 0.05); the expression of TYMS was observed at a high level in 76.2% of males and in 23.8% of females. The mean overall survival (OS) was 100 months for the CRC patients evaluated. The OS for patients with high expression of PD-L1 was 22 months. Patients with high expression of TYMS and DCC showed OS of 90 and 96 months, respectively. The results from this study suggest that PD-L1, TYMS, and DCC expression could be used as biomarkers to stratify CRC patients who could benefit from adjuvant therapy.

Immune checkpoint expression on peripheral cytotoxic lymphocytes in cervical cancer patients: moving beyond the PD-1/PD-L1 axis

Immune checkpoint therapy to reverse natural killer (NK) and T cell exhaustion has emerged as a promising treatment in various cancers. While anti-programmed cell death 1 (PD-1) pembrolizumab has recently gained Food and Drug Administration (FDA) approval for use in recurrent or metastatic cervical cancer, other checkpoint molecules, such as T cell immunoreceptor with immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibition motif (ITIM) domains (TIGIT) and T cell immunoglobulin and mucin-domain containing-3 (Tim-3), have yet to be fully explored in this disease. We report expression of TIGIT, Tim-3 and PD-1 on subsets of peripheral blood NK (CD56^dim/neg CD16^{bright/dim/neg} and CD56^bright CD16^dim/neg ) and T cells. The percentages of these cells were increased in women with cervical cancer and pre-malignant lesions. PD-1⁺ NK and T cells were likely to co-express TIGIT and/or Tim-3. These cells, with an apparently 'exhausted' phenotype, were augmented in patients. A subset of cells were also natural killer group 2 member D (NKG2D)- and DNAX accessory molecule 1 (DNAM-1)-positive. PD-1^int and PD-1^high T cells were notably increased in cervical cancer. Soluble programmed cell death ligand 1 (PD-L1) was higher in cancer patient blood versus healthy donors and we observed a positive correlation between sPD-L1 and PD-1⁺ T cells in women with low-grade lesions. Within the cancer group, there were no significant correlations between sPD-L1 levels and cervical cancer stage. However, when comparing cancer versus healthy donors, we observed an inverse association between sPD-L1 and total T cells and a correlation between sPD-L1 and CD56^dim NK cells. Our results may show an overview of the immune response towards pre-cancerous lesions and cervical cancer, perhaps giving an early clue as to whom to administer blocking therapies. The increase of multiple checkpoint markers may aid in identifying patients uniquely responsive to combined antibody therapies.

Enhanced T-Cell Maturation and Monocyte Aggregation Are Features of Cellular Inflammation in Human T-Lymphotropic Virus Type 1-Associated Myelopathy

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy (HAM) is an inflammatory condition characterized by severe disability and high levels of infected white blood cells. The circulating cellular inflammatory changes that distinguish this condition from asymptomatic infection are not well understood.

METHODS

To investigate the immune characteristics of individuals with low or high HTLV-1 proviral load (pVL), symptomatic disease, and the impact of immunosuppressive therapy, 38 women living with HTLV-1 infection, at a median age of 59 (52-68) years, were studied. Nineteen were asymptomatic carriers with low or high pVL; 19 were diagnosed with HAM, with 10 receiving anti-inflammatory therapy. Peripheral blood mononuclear cells were stained and analyzed for frequency distribution and activation of innate and adaptive immune cell subsets using multiparameter flow cytometry.

RESULTS

Inflation of the CD4:CD8 ratio (>2) was observed among all groups irrespective of pVL. The frequency of naive CD4+ T cells correlated inversely with HTLV-1 pVL (rs = -0.344, P = .026). Mature T effector memory TEM CD4+ T cells were expanded in patients with untreated HAM compared with asymptomatic carriers (P < .001) but less so in those on therapy. High levels of exhausted (PD-1+) and senescent (CD28null) CD4+ and CD8+ T cells were observed in all individuals, particularly in those with HAM, while monocytes showed increased aggregation and CD14+CD56- monocytes were less frequent.

CONCLUSIONS

CD4:CD8 ratio inflation is a feature of HTLV-1 infection, whereas enhanced CD4+ T cell maturation and monocyte aggregation are features of HAM, reflecting widespread inflammatory change, which may be detectable presymptomatically and be amenable to anti-inflammatory treatment.

MAL2 drives immune evasion in breast cancer by suppressing tumor antigen presentation

Immune evasion is a pivotal event in tumor progression. To eliminate human cancer cells, current immune checkpoint therapy is set to boost CD8+ T cell-mediated cytotoxicity. However, this action is eventually dependent on the efficient recognition of tumor-specific antigens via T cell receptors. One primary mechanism by which tumor cells evade immune surveillance is to downregulate their antigen presentation. Little progress has been made toward harnessing potential therapeutic targets for enhancing antigen presentation on the tumor cell. Here, we identified MAL2 as a key player that determines the turnover of the antigen-loaded MHC-I complex and reduces the antigen presentation on tumor cells. MAL2 promotes the endocytosis of tumor antigens via direct interaction with the MHC-I complex and endosome-associated RAB proteins. In preclinical models, depletion of MAL2 in breast tumor cells profoundly enhanced the cytotoxicity of tumor-infiltrating CD8+ T cells and suppressed breast tumor growth, suggesting that MAL2 is a potential therapeutic target for breast cancer immunotherapy.

Exploring the Potential Use of a PBMC-Based Functional Assay to Identify Predictive Biomarkers for Anti-PD-1 Immunotherapy

The absence of reliable, robust, and non-invasive biomarkers for anti- Programmed cell death protein 1 (PD-1) immunotherapy is an urgent unmet medical need for the treatment of cancer patients. No predictive biomarkers have been established based on the direct assessment of T cell functions, the primary mechanism of action of anti-PD-1 therapy. In this study, we established a model system to test T cell functions modulated by Nivolumab using anti-CD3 monoclonal antibody (mAb)-stimulated peripheral blood mononuclear cells (PBMCs), and characterized T cell functions primarily based on the knowledge gained from retrospective observations of patients treated with anti-PD-1 immunotherapy. During a comprehensive cytokine profile assessment to identify potential biomarkers, we found that Nivolumab increases expression of T helper type 1 (Th1) associated cytokines such as interferon-γ (IFN-γ) and interleukin-2 (IL-2) in a subset of donors. Furthermore, Nivolumab increases production of Th2, Th9, and Th17 associated cytokines, as well as many proinflammatory cytokines such as IL-6 in a subset of donors. Conversely, Nivolumab treatment has no impact on T cell proliferation, expression of CD25, CD69, or Granzyme B, and only modestly increases in the expansion of regulatory T cells. Our results suggest that assessment of cytokine production using a simple PBMC-based T cell functional assay could be used as a potential predictive marker for anti-PD-1 immunotherapy.

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.

Machine learning reveals a PD-L1-independent prediction of response to immunotherapy of non-small cell lung cancer by gene expression context

OBJECTIVE

Current predictive biomarkers for PD-1 (programmed cell death protein 1)/PD-L1 (programmed death-ligand 1)-directed immunotherapy in non-small cell lung cancer (NSCLC) mostly focus on features of tumour cells. However, the tumour microenvironment and immune context are expected to play major roles in governing therapy response. Against this background, we set out to apply context-sensitive feature selection and machine learning approaches on expression profiles of immune-related genes in diagnostic biopsies of patients with stage IV NSCLC.

METHODS

RNA expression levels were determined using the NanoString nCounter platform in formalin-fixed paraffin-embedded tumour biopsies obtained during the diagnostic workup of stage IV NSCLC from two thoracic oncology centres. A 770-gene panel covering immune-related genes and control genes was used. We applied supervised machine learning methods for feature selection and generation of predictive models.

RESULTS

Feature selection and model creation were based on a training cohort of 55 patients with recurrent NSCLC treated with PD-1/PD-L1 antibody therapy. Resulting models identified patients with superior outcomes to immunotherapy, as validated in two subsequently recruited, separate patient cohorts (n = 67, hazard ratio = 0.46, p = 0.035). The predictive information obtained from these models was orthogonal to PD-L1 expression as per immunohistochemistry: Selecting by PD-L1 positivity at immunohistochemistry plus model prediction identified patients with highly favourable outcomes. Independence of PD-L1 positivity and model predictions were confirmed in multivariate analysis. Visualisation of the models revealed the predictive superiority of the entire 7-gene context over any single gene.

CONCLUSION

Using context-sensitive assays and bioinformatics capturing the tumour immune context allows precise prediction of response to PD-1/PD-L1-directed immunotherapy in NSCLC.

Lymph-directed immunotherapy - Harnessing endogenous lymphatic distribution pathways for enhanced therapeutic outcomes in cancer

The advent of immunotherapy has revolutionised the treatment of some cancers. Harnessing the immune system to improve tumour cell killing is now standard clinical practice and immunotherapy is the first line of defence for many cancers that historically, were difficult to treat. A unifying concept in cancer immunotherapy is the activation of the immune system to mount an attack on malignant cells, allowing the body to recognise, and in some cases, eliminate cancer. However, in spite of a significant proportion of patients that respond well to treatment, there remains a subset who are non-responders and a number of cancers that cannot be treated with these therapies. These limitations highlight the need for targeted delivery of immunomodulators to both tumours and the effector cells of the immune system, the latter being highly concentrated in the lymphatic system. In this context, macromolecular therapies may provide a significant advantage. Macromolecules are too large to easily access blood capillaries and instead typically exhibit preferential uptake via the lymphatic system. In contexts where immune cells are the therapeutic target, particularly in cancer therapy, this may be advantageous. In this review, we examine in brief the current immunotherapy approaches in cancer and how macromolecular and nanomedicine strategies may improve the therapeutic profiles of these drugs. We subsequently discuss how therapeutics directed either by parenteral or mucosal administration, can be taken up by the lymphatics thereby accessing a larger proportion of the body's immune cells. Finally, we detail drug delivery strategies that have been successfully employed to target the lymphatics.

The Potential of Immune Checkpoint Blockade in Cervical Cancer: Can Combinatorial Regimens Maximize Response? A Review of the Literature

OPINION STATEMENT

Cervical cancer (CC) is most often caused by the human papillomavirus (HPV). In principle, these ties to the virus should make HPV tumors a relatively easy target for clearance by the immune system. However, these HPV-associated tumors have evolved strategies to escape immune attack. Checkpoint inhibition immunotherapy, which has had remarkable success in cancer treatment, has the potential to overcome the immune escape in CC by harnessing the patient's own immune system and priming it to recognize and kill tumors. Recent work involving PD-1/PD-L1 inhibitors in CC lends credence to this belief, as pembrolizumab has shown evidence of clinical efficacy and consequently been granted accelerated approval by the FDA. That being said, the oncologic outcomes following monotherapy with these biologics have mostly been modest and variable, and this can be attributed to alternative resistance mechanisms to tumor response. The use of therapies that stimulate immune responses via checkpoint-independent activation will therefore augment release of T cell inhibition by checkpoint inhibitors for stronger and more sustained clinical responses. Such a combinatorial approach holds promise for weak- or non-responders to checkpoint therapies as supported by evidence from various, recent pre-clinical, and preliminary clinical studies.

Role of Human Leukocyte Antigen System as A Predictive Biomarker for Checkpoint-Based Immunotherapy in Cancer Patients

Recent advances in cancer immunotherapy have clearly shown that checkpoint-based immunotherapy is effective in a small subgroup of cancer patients. However, no effective predictive biomarker has been identified so far. The major histocompatibility complex, better known in humans as human leukocyte antigen (HLA), is a very polymorphic gene complex consisting of more than 200 genes. It has a crucial role in activating an appropriate host immune response against pathogens and tumor cells by discriminating self and non-self peptides. Several lines of evidence have shown that down-regulation of expression of HLA class I antigen derived peptide complexes by cancer cells is a mechanism of tumor immune escape and is often associated to poor prognosis in cancer patients. In addition, it has also been shown that HLA class I and II antigen expression, as well as defects in the antigen processing machinery complex, may predict tumor responses in cancer immunotherapy. Nevertheless, the role of HLA in predicting tumor responses to checkpoint-based immunotherapy is still debated. In this review, firstly, we will describe the structure and function of the HLA system. Secondly, we will summarize the HLA defects and their clinical significance in cancer patients. Thirdly, we will review the potential role of the HLA as a predictive biomarker for checkpoint-based immunotherapy in cancer patients. Lastly, we will discuss the potential strategies that may restore HLA function to implement novel therapeutic strategies in cancer patients.

All in the Levels-Programmed Death-Ligand 1 Expression as a Biomarker for Immune Checkpoint Inhibitor Response in Patients with Gastrointestinal Cancer

Immune checkpoint inhibitors (ICIs) benefit patients with rare subsets of gastrointestinal (GI) cancer. Significant interest exists to identify predictive biomarkers that may increase the applicability of ICI therapy for these patients. Programmed death ligand 1 (PD-L1) is one such candidate; however, this biomarker has well-chronicled limitations. Combined positive score (CPS) ≥1 is the minimum PD-L1 expression threshold necessary for patients with gastric or gastroesophageal junction (GEJ) cancer to qualify for treatment with pembrolizumab; however, studies suggest that patients with higher CPS scores may derive greater benefit. We present the cases of two patients, both with low tumor mutational burden, microsatellite stable, and CPS ≥70 GI tumors (cholangiocarcinoma and GEJ cancer), who have achieved excellent tumor control with pembrolizumab. We postulate that, by testing for CPS in all patients with GI cancer and identifying a CPS threshold predictive of ICI response, PD-L1 expression could identify the patiets with GI cancer, in tissue agnostic fashion, who could benefit from ICI therapy.

Higher serum PD-L1 level predicts increased overall survival with lapatinib versus trastuzumab in the CCTG MA.31 phase 3 trial

BACKGROUND

The purpose of this retrospective biomarker study of the Canadian Cancer Trials Group (CCTG) MA.31 randomized phase 3 trial (lapatinib vs trastuzumab) of HER2-positive metastatic breast cancer (MBC) was to evaluate the prognostic and predictive biomarker utility of pretreatment serum programmed death ligand 1 (PD-L1) levels.

METHODS

CCTG MA.31 accrued 652 HER2-positive patients; 387 had serum available (185 in the trastuzumab arm and 202 in the lapatinib arm). The Ella immunoassay platform (ProteinSimple, San Jose, California) was used to quantitate serum PD-L1 levels. Stepwise forward Cox multivariable analyses were performed for progression-free survival and overall survival (OS).

RESULTS

In the whole trial population, continuous pretreatment serum PD-L1 levels were not associated with OS. However, within the trastuzumab arm, a higher continuous pretreatment serum PD-L1 level was significant for shorter OS (hazard ratio [HR], 3.85; P = .04), but within the lapatinib arm, pretreatment serum PD-L1 was not associated with OS (P = .37). In the whole trial, in a multivariable analysis for OS, serum PD-L1 (median cut point) remained a significant independent covariate (HR, 2.38; P = .001). There was a significant interaction between treatment arm and continuous serum PD-L1 (bootstrap method; P = .0025): at or above 214.2 pg/mL (the 89th percentile), serum PD-L1 was associated with significantly shorter OS with trastuzumab treatment versus lapatinib treatment.

CONCLUSIONS

In the CCTG MA.31 trial, serum PD-L1 was a significant predictive factor: a higher pretreatment serum PD-L1 level was associated with shorter OS with trastuzumab treatment but with longer OS with lapatinib treatment. Immune evasion may decrease the effectiveness of trastuzumab therapy. Further evaluation of elevated serum PD-L1 in advanced breast cancer is warranted to identify patients with HER2-positive MBC who may benefit from novel immune-targeted therapies in addition to trastuzumab.

Promising predictors of checkpoint inhibitor response in NSCLC

INTRODUCTION

The development of immune-checkpoint inhibitors targeting the programmed death-1 (PD-1) and its ligand (PD-L1) axis has transformed the treatment paradigm in non-small-cell lung cancer, bringing about unprecedented 5-year survival rates. Despite this dramatic improvement, roughly 70% of patients do not derive durable benefit from these treatments, illustrating the need for predictive biomarkers.

AREAS COVERED

In this review, we will discuss what makes a successful biomarker and analyze the role and significance of currently available options, including PD-L1, oncogenic alterations and tumor mutation burden. We then discuss potential biomarkers on the horizon, including the microbiome, tumor infiltrating lymphocytes, neutrophil-to-lymphocyte ratio, gene signatures and the emerging field of multiomics.

EXPERT OPINION

To date, only PD-L1 is clinically validated as a positive predictor of response to immunotherapy, yet the need to refine patient selection has never been stronger, given the indication for checkpoint inhibitors alone or in combination in all non-oncogene driven non-small-cell lung cancer patients receiving front-line therapy. Prospective validation of the above-mentioned potential biomarkers, either alone or in combination, may help to elaborate improved predictive tools.

An Overview of Promising Biomarkers in Cancer Screening and Detection

Applications of biomarkers have been proved in oncology screening, diagnosis, predicting response to treatment as well as monitoring the progress of the disease. Considering the crucial role played by them during different disease stages, it is extremely important to evaluate, validate, and assess them to incorporate them into routine clinical care. In this review, the role of few most promising and successfully used biomarkers in cancer detection, i.e. PD-L1, E-Cadherin, TP53, Exosomes, cfDNA, EGFR, mTOR with regard to their structure, mode of action, and reports signifying their pathological significance, are addressed. Also, an overview of some successfully used biomarkers for cancer medicine has been presented. The study also summarizes biomarker-driven personalized cancer therapy i.e., approved targets and indications, as per the US FDA. The review also highlights the increasingly prominent role of biomarkers in drug development at all stages, with particular reference to clinical trials. The increasing utility of biomarkers in clinical trials is clearly evident from the trend shown, wherein ~55 percent of all oncology clinical trials in 2019 were seen to involve biomarkers, as opposed to ~ 15 percent in 2001, which clearly proves the essence and applicability of biomarkers for synergizing clinical information with tumor progression. Still, there are significant challenges in the implementation of these possibilities with strong evidence in cost-- effective manner.

Association between PD-L1 status and immune checkpoint inhibitor response in advanced malignancies: a systematic review and meta-analysis of overall survival data

BACKGROUND

Targeting the programmed death ligand 1 (PD-L1) pathway has become standard for many advanced malignancies. Whether PD-L1 expression predicts response is unclear. We assessed the association between PD-L1 expression and immunotherapy response using stratified meta-analysis.

METHODS

We performed a systematic review of randomized clinical trials published prior to October 2018 comparing overall survival (OS) in patients with advanced solid organ malignancies treated with immunotherapy or standard treatment. Pooled hazard ratios were calculated among patients with high and low PD-L1 levels independently. Differences between the two estimates were assessed using meta-analysis of study-level differences. Our primary analysis assessed a 1% threshold while secondary analyses utilized 5, 10 and 50%.

RESULTS

14 eligible trials reporting on 8887 patients were included. While there was a significant OS benefit for immunotherapy compared with standard treatment for all patients, the magnitude of benefit was significantly larger among those with high PD-L1 expression (P = 0.006). This finding persisted regardless of threshold used and across subgroup analyses according to PD-L1 assay type, tumor histology, line of therapy, type of inhibitor and study methodology.

CONCLUSIONS

PD-L1 levels have important predictive value in determining the response to immunotherapy. However, patients with low PD-L1 levels also experience improved survival with immunotherapy compared with standard treatment.

Immuno-Oncotherapeutic Approaches in Advanced Hepatocellular Carcinoma

Advanced hepatocellular carcinoma has limited treatment options, but there has been extensive growth recently with cabozantinib, regorafenib, lenvatinib, nivolumab, atezolizumab, and bevacizumab, which are some of the treatments that have received FDA approval just over the last three years. Because HCC tumor microenvironment is potentially immunogenic and typically characterized by inflammation, immunotherapy has been proposed as a potential novel therapeutic approach, which has prompted studies in advanced HCC patients investigating various immune-therapeutic strategies such as CAR-T cell therapy, checkpoint inhibitors, and onco-vaccines. The anti-PD-1 checkpoint inhibitors nivolumab and pembrolizumab have been FDA approved as a second line treatment in patients who progressed or are intolerant to Sorafenib. To build up on the success of PD-1 monotherapy, combinatorial regimens with PD-1/PD-L1 inhibitors plus VEGF targeted agents have shown positive results in various malignancies including HCC. The combination of atezolizumab plus bevacizumab is the new addition to the HCC treatment armamentarium following a pivotal study that demonstrated an improvement in OS over frontline sorafenib. Other novel immune-based approaches and oncolytic viruses are in the early phases of clinical evaluation. These innovative approaches enhance the intensity of cancer-directed immune responses and will potentially impact the outlook of this aggressive disease.

MiR-92 overexpression suppresses immune cell function in ovarian cancer via LATS2/YAP1/PD-L1 pathway

PURPOSE

Increasing evidence suggested that microRNA plays an important role in ovarian cancer. In this study, the role of miR-92 in ovarian cancer was investigated.

METHODS

In this study, miR-92 expression in clinical sample was evaluated, role of miR-92 was investigated in vitro, and underlying mechanism was investigated using Chip, co-IP, and western blot.

RESULTS

In this study, we show that miR-92 is overexpressed in ovarian cancer tissue compared with normal cancer tissue. Transfection of miR-92 increased proliferation of ovarian cancer cell, and increased migration capacity and colony formation were observed after miR-92 transfection; we found that expression of LATS2 was decreased by miR-92, and this was further confirmed by luciferase assay, which proved that miR-92 is targeting 3' of the endogenous LATS2 gene. Downregulation of LATS2 resulted in increased translocation of YAP1 and upregulation of PD-L1, which subsequently suppressed NK cell function and promoted T cell apoptosis. Moreover, co-transfection of YAP1-targeted shRNA could relieve miR-92-induced immune suppression effect. Mechanically, immunoprecipitation (IP) was used to show that LATS2 interacted with YAP1 and subsequently limited nuclear translocation of YAP1; chromatin immunoprecipitation (ChIP) was used to confirm that YAP1 could bind to enhancer region of PD-L1 to enhance transcription activity of PD-L1.

CONCLUSIONS

Our data revealed a novel mechanism which finally resulted in immune suppression in ovarian cancer.

Resistance to chemoimmunotherapy in non-small-cell lung cancer

Recent clinical trials evaluating the combination of chemotherapy with immune checkpoint inhibition for the primary treatment of lung cancer showed increased progression-free and overall survival compared with chemotherapy alone. However, the combination of these two modalities is less than additive and the mechanisms of resistance to this therapeutic intervention are discussed here. So far, the conventional biomarkers for immunotherapy, namely programmed death-ligand 1 expression or tumor mutational burden are poor predictors of the efficacy of immunochemotherapy, and the optimal sequence of chemotherapy and immunotherapy has yet to be defined.

Responses of metastatic primary fallopian tube carcinoma to pembrolizumab and nab-paclitaxel: A case report

RATIONALE

Primary fallopian tube carcinoma (PFTC) is an extremely rare but invasive malignancy with a dismal prognosis. Very few data exist on the salvage treatment for patients with PFTC. Here we report a case showing an impressive response to immunotherapy combined with chemotherapy, which have never been reported before on patients with metastatic PFTC.

PATIENT CONCERNS

A 42-year-old woman, who was diagnosed with PFTC in 2010, had been failed of multiple systemic therapies and antiangiogenic therapy because of the disease recurrence and progression.

DIAGNOSIS

Metastatic primary fallopian tube carcinoma.

INTERVENTIONS

The patient underwent surgery in May 2010 and had multi-line chemotherapies plus an anti-vascular endothelial growth factor (anti-VEGF) monoclonal antibody for about 9 years. Due to treatment failure the patient accepted the immunotherapy with the checkpoint inhibitor, pembrolizumab, combined with nab-paclitaxel from December 2018 to April 2019.

OUTCOMES

The patient showed a complete response after 6 cycles treatment. Thus far, the patient is taking pembrolizumab as maintenance and remains in good health.

LESSONS

Pembrolizumab combined with chemotherapy for treatment of PFTC may provide a positive antitumor effect in multiple metastatic lesions, but more clinical evidence is needed to confirm the efficacy and safety.

Phagocyte-membrane-coated and laser-responsive nanoparticles control primary and metastatic cancer by inducing anti-tumor immunity

To achieve safe and effective antitumor immunity, we constructed the M1-macrophage-membrane-coated nanoparticles [(C/I)BP@B-A(D)&M1m] having laser-responsive, size-changeable, on-demand drug release and prolonged circulation retention properties. (C/I)BP@B-A(D)&M1m delayed clearance by the phagocytic system and homed to tumor efficiently. Upon 650 nm laser irradiation, the hydrophobic core of the PEGylated bilirubin nanoparticles (BP) got disrupted, releasing small-sized deep-penetrating B-A(D) particles, photosensitive chlorin e6 (C), and tolerance-inducing indoleamine 2,3-dioxygenase inhibitor, indoximode (I). Treatment-induced immunogenic cell death and antitumor immunity, suppressing primary tumor growth in both 4T1 and B16F10 models without causing any adverse effects. Most importantly, it inhibited primary tumor recurrence as well as metastasis. Thus, this study provides a promising combinatorial strategy to trigger antitumor immunity in malignancies.

Systemic Therapy in Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma- A Systematic Review and Meta-Analysis

BACKGROUND

The most effective regimen is unclear for patients with recurrent or metastatic head and neck squamous cell carcinomas (R/M HNSCC). We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) investigating only systemic therapy for R/M HNSCC.

METHODS

This systematic review followed PRISMA and the Cochrane Collaboration Handbook for Systematic Reviews of Interventions. Endpoints included overall survival (OS), progression-free survival (PFS) and overall response rates (ORR).

RESULTS

55 RCTs from 1990-November 2019 qualified for review (n=12132). Only PD-1/PDL-1 inhibitors increased OS in R/M HNSCC platinum-resistant disease against their control (HR = 0·79, 95%CI 0·70-0.90, p<0·001), especially for PD-L1 ≥ 1% expressing tumours (HR = 0·72, 95%CI 0·60-0·86, p<0·001). PFS was prolonged for anti-EGFR agents against methotrexate when used in a second line setting (HR = 0·74, 95 %CI 0·62-0·87, p=0·001), and when cetuximab (HR = 0·60, 95%CI 0·49-0·72, p<0·0001) and panitumumab (HR = 0·76, 95%CI 0·65-0·89, p=0·001) were introduced to platinum-based regimens for first-line treatment.

CONCLUSIONS

PD-1/PD-L1 inhibitors may represent the future of R/M HNSCC treatment. However, EGFR inhibitors may still play improve clinical outcomes.

Microenvironment Analysis of Prognosis and Molecular Signature of Immune-Related Genes in Lung Adenocarcinoma

There is growing evidence on the clinical significance of tumor microenvironment (TME) cells in predicting prognosis and therapeutic effects. However, cell interactions in tumor microenvironments have not been thoroughly studied or systematically analyzed so far. In this study, 22 immune cell components in the lung adenocarcinoma (LUAD) TME were analyzed using gene expression profile from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). The TME-based molecular subtypes of LUAD were defined to evaluate further the relationship between molecular subtypes, prognosis, and clinical characteristics. A TME risk score model was constructed by using the differentially expressed genes (DEGs) of molecular subtypes. The relationship between the TME score and clinical characteristics and genomic mutations was compared to identify the genes that have significant associations with the TME. The comprehensive analysis of the TME characteristics may be helpful in revealing the response of LUAD patients to immunotherapy, providing a new strategy for immunotherapy.

Prolonged Response to Pembrolizumab in Spindle Cell Squamous Cell Carcinoma Metastatic to the Central Nervous System

Background. Cutaneous squamous cell carcinoma is a common type of skin cancer, with aggressive metastatic or locally advanced disease representing an uncommon minority of presentations. Emerging data have supported the Food and Drug Administration approval of the anti-PD1 human monoclonal antibody cemiplimab in select patients with advanced disease. However, there is limited data regarding durability of effect and generalizability of anti-PD1 effectiveness across therapies. Additionally, information regarding applicability of these regimens to the rare spindle cell variant and to central nervous system metastases for cutaneous squamous cell carcinoma is unfortunately limited. Case Presentation. A 72-year-old gentleman presented with facial neurological deficits and a dermal nodule and was diagnosed with spindle cell squamous cell carcinoma with perineural invasion. His course was notable for early intracranial metastasis with progressive neurological deficits despite recurrent radiation therapy with intermittent response. When progressive left-sided weakness prompted imaging evaluation that was concerning for disease recurrence after exhaustion of radiation therapy options, the patient was started on systemic therapy with the anti-PD-1 monoclonal antibody treatment prior to the approval of cemiplimab. Pembrolizumab was chosen due to the fact that the patient was ineligible for clinical trials and for its every 21-day dosing. With this treatment, he has achieved a durable clinical response, resulting in near resolution of neurological deficits and more than a year of progression-free survival to date, despite aggressive intracranial disease. Conclusions. This case suggests that anti-PD-1 therapy with pembrolizumab may represent an effective and well-tolerated treatment for patients with metastatic spindle cell squamous cell carcinoma including patients with metastatic disease to the central nervous system.

A metastatic intrahepatic cholangiocarcinoma treated with programmed cell death 1 inhibitor: a case report and literature review

Intrahepatic cholangiocarcinoma is a disease with grave prognosis due to limited therapeutic regimens. Programmed cell death 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitor have shown dramatic clinical effectiveness in multiple solid tumors. Here, we report the case that a patient with metastasis intrahepatic cholangiocarcinoma, being failure of first-line chemotherapy, was enrolled into the Phase I study of a PD-1 inhibitor, sintilimab. The patient achieved complete remission after three cycles of treatment with mild adverse reaction. In addition, the tumor mutational burden and the microsatellite instability status were low in the present case. Hence, PD-1 inhibitor might be a promising therapeutic approach for patients with advanced cholangiocarcinoma.

Inhibition of Vps34 reprograms cold into hot inflamed tumors and improves anti-PD-1/PD-L1 immunotherapy

One of the major challenges limiting the efficacy of anti-PD-1/PD-L1 therapy in nonresponding patients is the failure of T cells to penetrate the tumor microenvironment. We showed that genetic or pharmacological inhibition of Vps34 kinase activity using SB02024 or SAR405 (Vps34i) decreased the tumor growth and improved mice survival in multiple tumor models by inducing an infiltration of NK, CD8⁺, and CD4⁺ T effector cells in melanoma and CRC tumors. Such infiltration resulted in the establishment of a T cell-inflamed tumor microenvironment, characterized by the up-regulation of pro-inflammatory chemokines and cytokines, CCL5, CXCL10, and IFNγ. Vps34i treatment induced STAT1 and IRF7, involved in the up-regulation of CCL5 and CXCL10. Combining Vps34i improved the therapeutic benefit of anti-PD-L1/PD-1 in melanoma and CRC and prolonged mice survival. Our study revealed that targeting Vps34 turns cold into hot inflamed tumors, thus enhancing the efficacy of anti-PD-L1/PD-1 blockade.

Identification of Potential Biomarkers for Anti-PD-1 Therapy in Melanoma by Weighted Correlation Network Analysis

Melanoma is the most malignant form of skin cancer, which seriously threatens human life and health. Anti-PD-1 immunotherapy has shown clinical benefits in improving patients' overall survival, but some melanoma patients failed to respond. Effective therapeutic biomarkers are vital to evaluate and optimize benefits from anti-PD-1 treatment. Although the establishment of immunotherapy biomarkers is well underway, studies that identify predictors by gene network-based approaches are lacking. Here, we retrieved the existing datasets (GSE91061, GSE78220 and GSE93157, 79 samples in total) on anti-PD-1 therapy to explore potential therapeutic biomarkers in melanoma using weighted correlation network analysis (WGCNA), function validation and clinical corroboration. As a result, 13 hub genes as critical nodes were traced from the key module associated with clinical features. After receiver operating characteristic (ROC) curve validation by an independent dataset (GSE78220), six hub genes with diagnostic significance were further recovered. Moreover, these six genes were revealed to be closely associated not only with the immune system regulation, immune infiltration, and validated immunotherapy biomarkers, but also with excellent prognostic value and significant expression level in melanoma. The random forest prediction model constructed using these six genes presented a great diagnostic ability for anti-PD-1 immunotherapy response. Taken together, IRF1, JAK2, CD8A, IRF8, STAT5B, and SELL may serve as predictive therapeutic biomarkers for melanoma and could facilitate future anti-PD-1 therapy.

Cancer Biomarker Discovery for Precision Medicine: New Progress

BACKGROUND

Precision medicine puts forward customized healthcare for cancer patients. An important way to accomplish this task is to stratify patients into those who may respond to a treatment and those who may not. For this purpose, diagnostic and prognostic biomarkers have been pursued.

OBJECTIVE

This review focuses on novel approaches and concepts of exploring biomarker discovery under the circumstances that technologies are developed, and data are accumulated for precision medicine.

RESULTS

The traditional mechanism-driven functional biomarkers have the advantage of actionable insights, while data-driven computational biomarkers can fulfill more needs, especially with tremendous data on the molecules of different layers (e.g. genetic mutation, mRNA, protein etc.) which are accumulated based on a plenty of technologies. Besides, the technology-driven liquid biopsy biomarker is very promising to improve patients' survival. The developments of biomarker discovery on these aspects are promoting the understanding of cancer, helping the stratification of patients and improving patients' survival.

CONCLUSION

Current developments on mechanisms-, data- and technology-driven biomarker discovery are achieving the aim of precision medicine and promoting the clinical application of biomarkers. Meanwhile, the complexity of cancer requires more effective biomarkers, which could be accomplished by a comprehensive integration of multiple types of biomarkers together with a deep understanding of cancer.

Predominance of Central Memory T Cells with High T-Cell Receptor Repertoire Diversity is Associated with Response to PD-1/PD-L1 Inhibition in Merkel Cell Carcinoma

PURPOSE

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer, which can be effectively controlled by immunotherapy with PD-1/PD-L1 checkpoint inhibitors. However, a significant proportion of patients are characterized by primary therapy resistance. Predictive biomarkers for response to immunotherapy are lacking.

EXPERIMENTAL DESIGN

We applied Bayesian inference analyses on 41 patients with MCC testing various clinical and biomolecular characteristics to predict treatment response. Further, we performed a comprehensive analysis of tumor tissue-based immunologic parameters including multiplexed immunofluorescence for T-cell activation and differentiation markers, expression of immune-related genes and T-cell receptor (TCR) repertoire analyses in 18 patients, seven objective responders, and 11 nonresponders.

RESULTS

Bayesian inference analyses demonstrated that among currently discussed biomarkers only unimpaired overall performance status and absence of immunosuppression were associated with response to therapy. However, in responders, a predominance of central memory T cells and expression of genes associated with lymphocyte attraction and activation was evident. In addition, TCR repertoire usage of tumor-infiltrating lymphocytes (TILs) demonstrated low T-cell clonality, but high TCR diversity in responding patients. In nonresponders, terminally differentiated effector T cells with a constrained TCR repertoire prevailed. Sequential analyses of tumor tissue obtained during immunotherapy revealed a more pronounced and diverse clonal expansion of TILs in responders indicating an impaired proliferative capacity among TILs of nonresponders upon checkpoint blockade.

CONCLUSIONS

Our explorative study identified new tumor tissue-based molecular characteristics associated with response to anti-PD-1/PD-L1 therapy in MCC. These observations warrant further investigations in larger patient cohorts to confirm their potential value as predictive markers.

Multicentre study on the consistency of PD-L1 immunohistochemistry as predictive test for immunotherapy in non-small cell lung cancer

AIMS

Investigate the impact of interlaboratory- and interobserver variability of immunohistochemistry on the assessment of programmed death ligand 1 (PD-L1) in non-small cell lung cancer (NSCLC).

METHODS

Two tissue microarrays (TMAs) were constructed from 50 (TMA-A) and 51 (TMA-B) resected NSCLC cases, and distributed among eight centres. Immunostaining for PD-L1 was performed using Agilent's 22C3 pharmDx Assay (pharmDx) and/or a 22C3 laboratory developed test (LDT). The interlaboratory variability of staining- and interobserver variability of scoring for PD-L1 were assessed in selected critical samples (samples at the cut-off of positivity) and non-critical samples. Also, PD-L1 epitope deterioration in time in stored unstained slides was analysed. Krippendorff's alpha values (0=maximal, 1=no variability) were calculated as measure for variability.

RESULTS

For interlaboratory variability of immunostaining, the percentage of PD-L1 positive cases among centres ranged 40%-51% (1% cut-off) and 23%-30% (50% cut-off). Alpha values at 1% cut-off were 0.88 (pharmDx) and 0.87 (LDT) and at 50% cut-off 0.82 (pharmDx) and 0.95 (LDT). Interobserver variability of scoring resulted in PD-L1 positive cases ranging 29%-55% (1% cut-off) and 14%-30% (50% cut-off) among pathologists. Alpha values were at 1% cut-off 0.83 (TMA-A) and 0.66 (TMA-B), and at 50% cut-off 0.77 (TMA-A) and 0.78 (TMA-B). Interlaboratory variability of staining was higher (p<0.001) in critical samples than in non-critical samples at 50% cut-off. Furthermore, PD-L1 epitope deterioration in unstained slides was observed after 12 weeks.

CONCLUSIONS

The results provide insight in factors contributing to variability of immunohistochemical assessment of PD-L1, and contribute to more reliable predictive testing for PD-L1.

MiR-214 prevents the progression of diffuse large B-cell lymphoma by targeting PD-L1

Objective

We explored the role and mechanism of miR-214 involvement in the progression of diffuse large B-cell lymphoma (DLBCL).

Methods

The expression levels of miR-214 and PD-L1 in human DLBCL cell lines and in tissue samples from patients with DLBCL were determined using quantitative RT-PCR. The dual-luciferase reporter assay was employed to determine the correlation between the expressions of miR-214 and PD-L1. Cell viability, invasiveness and apoptosis were respectively examined in cells of the DLBCL line OCI-Ly3 using CCK-8, transwell and flow cytometry assays. The expression level of PD-L1 was determined via immunoblotting. Inflammatory cytokine secretion was determined via enzyme-linked immune sorbent assay (ELISA).

Results

miR-214 was downregulated and PD-L1 was upregulated in DLBCL tissues and cell lines in comparison to normal adjacent tissues or normal B-cell. This indicates a negative correlation in the expression levels. Overexpression of miR-214 inhibited cell viability and invasion and induced apoptosis of OCI-Ly3 cells. Moreover, miR-214 was shown to target PD-L1 mRNA by binding to its 3′-untranslated region (UTR). Knockdown of PD-L1 attenuated the malignant phenotype of OCI-Ly3 cells. Overexpression of miR-214 inhibited tumor growth by targeting PD-L1 in vivo.

Conclusion

By targeting PD-L1, miR-214 regulates the progression of DLBCL in vitro and in vivo.

Delivery strategies of cancer immunotherapy: recent advances and future perspectives

Immunotherapy has become an emerging strategy for the treatment of cancer. Immunotherapeutic drugs have been increasing for clinical treatment. Despite significant advances in immunotherapy, the clinical application of immunotherapy for cancer patients has some challenges associated with safety and efficacy, including autoimmune reactions, cytokine release syndrome, and vascular leak syndrome. Novel strategies, particularly improved delivery strategies, including nanoparticles, scaffolds, and hydrogels, are able to effectively target tumors and/or immune cells of interest, increase the accumulation of immunotherapies within the lesion, and reduce off-target effects. Here, we briefly describe five major types of cancer immunotherapy, including their clinical status, strengths, and weaknesses. Then, we introduce novel delivery strategies, such as nanoparticle-based delivery of immunotherapy, implantable scaffolds, injectable biomaterials for immunotherapy, and matrix-binding molecular conjugates, which can improve the efficacy and safety of immunotherapies. Also, the limitations of novel delivery strategies and challenges of clinical translation are discussed.

Lyophilizable and Multifaceted Toll-like Receptor 7/8 Agonist-Loaded Nanoemulsion for the Reprogramming of Tumor Microenvironments and Enhanced Cancer Immunotherapy

The low therapeutic efficacy of current cancer immunotherapy is related to nonimmunogenic and immunosuppressive tumor microenvironments (TMEs). To overcome these limitations, both the immune priming of antitumoral lymphocytes and the reprogramming of immunosuppressive factors in TMEs are essential. Here, we suggest a nanoemulsion (NE)-based immunotherapeutic platform that can not only modulate tumor-induced suppression but also induce an effective cell-mediated immune response for T cell proliferation. Multifunctional NEs can be fabricated by integrating the efficacy of NEs as delivery systems and the multifaceted immunomodulation characteristics (i.e., immunostimulation and reprogramming of immunosuppression) of small molecule-based Toll-like receptor 7/8 agonists. Local in situ vaccination of melanoma and cervical tumor models with tumor antigens (protein and peptide) adjuvanted with NE loaded with TLR7/8 agonists [NE (TLR7/8a)] induced the recruitment and activation of innate immune cells, infiltration of lymphocytes, and polarization of tumor-associated M2 macrophages, which resulted in inhibition of tumor growth and prolonged survival in both primary and rechallenged tumor models. Antibody-depletion experiments also suggested that macrophages, type I IFN (IFN-α and IFN-β), CD8⁺ T cells, and NK1.1⁺ cells contributed to the antitumor effect of NE (TLR7/8a). The combination of antitumoral lymphocytes and reprogramming of immunosuppressive TMEs induced by NE (TLR7/8a) treatment evoked a synergistic antitumor immune response with immune checkpoint blockade therapy (anti-PD-1 and anti-PD-L1).

Immune checkpoint inhibitors: a promising anticancer therapy

Immune checkpoint inhibitors (ICIs) are revolutionizing the treatment of many cancers and have demonstrated their potential as 'cancer terminators'. However, ICI treatment also has constraints, such as its immune-related adverse events (irAEs) and therapeutic resistance. These drawbacks are gradually being overcome through better knowledge of the immune system, history of disease, duration of treatment, combinational drug regimes, adequate biomarkers, and effective patient response monitoring. In this review, we discuss the present ICI therapy landscape and its therapeutic outcomes for various diseases. We also highlight biomarkers related to the ICI response.

An update: circulating tumor cells in head and neck cancer

Introduction: Local and distant metastatic disease occurs in approximately half of head and neck squamous cell carcinoma (HNSCC) patients, representing an ongoing cause for treatment failure. Circulating tumor cells (CTCs) are transient cancer cells which have the capacity to metastasize to distant sites such as the lungs and liver in HNSCC. When metastatic disease is radiographically evident, the patient prognosis is often poor. Therefore, methodologies to assess micrometastatic disease are needed to (1) identify patients likely to develop metastatic disease and (2) treat and monitor these patients more aggressively. Whilst CTCs are well documented in other tumor streams such as breast, colorectal cancer and prostate cancers, the data and clinical utility in HNSCC remains limited.Areas covered: Here we summarize the recent advances of CTCs and applications in HNSCC.Expert opinion: CTC enumeration can be prognostic in HNSCC; further studies are warranted to investigate the role of CTC clusters in HNSCC; CTC culture (in vivo/ex vivo) may present a possibility to expand these rare cells to a critical mass for functional testing; PD-L1 expression of HNSCC CTCs may present a means by which to determine patients likely to respond to therapy; a HNSCC CTC-specific marker is warranted.

Antigen-Presenting Cell-Intrinsic PD-1 Neutralizes PD-L1 in cis to Attenuate PD-1 Signaling in T Cells

The PD-1 pathway, consisting of the co-inhibitory receptor PD-1 on T cells and its ligand (PD-L1) on antigen-presenting cells (APCs), is a major mechanism of tumor immune evasion. PD-1 and PD-L1 blockade antibodies have produced remarkable clinical activities against a subset of cancers. Binding between T cell-intrinsic PD-1 and APC-intrinsic PD-L1 triggers inhibitory signaling to attenuate the T cell response. Here, we report that PD-1 is co-expressed with PD-L1 on tumor cells and tumor-infiltrating APCs. Using reconstitution and cell culture assays, we demonstrate that the co-expressed PD-1 binds to PD-L1 in cis. Such interaction inhibits the ability of PD-L1 to bind T cell-intrinsic PD-1 in trans and, in turn, represses canonical PD-L1/PD-1 inhibitory signaling. Selective blockade of tumor-intrinsic PD-1 frees up tumor-intrinsic PD-L1 to inhibit T cell signaling and cytotoxicity. Our study uncovers another dimension of PD-1 regulation, with important therapeutic implications.

Listeria-based hepatocellular carcinoma vaccine facilitates anti-PD-1 therapy by regulating macrophage polarization

Recently, patients with advanced cancers have been benefited greatly from immune checkpoint blockade immunotherapy. However, immune checkpoint blockade is still suboptimal in HCC treatment and more immune modifications are needed to achieve an efficient therapeutic goal. Here, we investigated the combined administration of a Listeria-based HCC vaccine, Lmdd-MPFG, and the anti-PD-1 immune checkpoint blockade antibody. We found that Lmdd-MPFG promoted the expression of PD-L1 in HCC cells but resensitized the tumor local T cell to respond to the anti-PD-1 immunotherapy. Mechanistically, the Lmdd-MPFG vaccine activates the NF-κB pathway in the tumor-associated macrophages (TAMs) through the TLR2 and MyD88 pathway, and recruits p62 to activate the autophagy pathway. The overall effect is skewing the TAMs from M2-polarized TAMs into the M1-polarized TAMs. Most importantly, it skewed the cytokine profiles into antitumor one in the tumor microenvironment (TME). This change restores the T-cell reactivity to the anti-PD-1 blockade. Our results suggested that Lmdd-MPFG combined with PD-1 blockade exerted synergistic antitumor effects through modifying TAMs in the TME and removing T-cell inhibitory signals, thereby providing a new potential strategy for HCC treatment.

Immunotherapy in the management of squamous cell carcinoma of the head and neck

Despite many advances in surgery, radiotherapy, and systemic treatments, only modest improvements in survival, function, and quality of life have been achieved after treatment of squamous cell carcinoma (SCC) of the head and neck. With a better understanding of the biology and genetics of tumours, the emergence of a paradigm shift towards the further development of non-surgical treatments may result in less morbidity and better outcomes than are seen currently. SCC of the head and neck is known to be a complex disease that has a sophisticated interaction with the human immune system. At the forefront of emerging treatments is immunotherapy, which has already been established in many other areas of oncology. The rapidly evolving nature of immunotherapeutic agents and, sometimes, their complex mechanisms can make the understanding of these concepts challenging, and could discourage clinicians from engaging in clinical trials. The aim of this paper therefore was to review the current premise for immunotherapeutic approaches, and to provide a contemporary evidence-based rationale for their use.

Pembrolizumab for anaplastic thyroid cancer: a case study

Blockade of the PD-1/PD-L1 pathway with targeted monoclonal antibodies has demonstrated encouraging anti-tumour activity in multiple cancer types. We present the case of a patient with BRAF-negative stage IVC anaplastic thyroid cancer (ATC) treated with the anti-PD-1 monoclonal antibody, pembrolizumab, following radiographic progression on chemoradiation. Blood samples were collected prior to and at four time points during treatment with pembrolizumab. Mass cytometry was used to determine expression of relevant biomarkers by peripheral blood mononuclear cells. Faecal samples were collected at baseline and 4 weeks following treatment initiation; taxonomic profiling using 16S ribosomal RNA (rRNA) gene sequencing was performed. Following treatment, a marked expansion in CD20⁺ B cell, CD16⁺ CD56^lo NK cell and CD45RO⁺ CCR7⁺ central memory CD4⁺ T-cell populations was observed in the peripheral blood. Proportions of cells expressing the co-receptors TIGIT, OX40 and CD86 also increased during treatment. A high abundance of bacteria of the order Bacteroidales, specifically from the Bacteroidaceae and Rikenellaceae families, was identified in the faecal microbiota. Moreover, the patient's microbiome was enriched in Clostridiales order members Ruminococcaceae, Veillonellaceae and Lachnospiraceae. Alpha diversity of the gut microbiome was significantly higher following initiation of checkpoint therapy as assessed by the Shannon and Simpson index. Our results suggest that treatment with pembrolizumab promotes expansion of T-, B- and NK cell populations in the peripheral blood at the time of tumour regression and have the potential to be implemented as predictive biomarkers in the context of checkpoint blockade therapy. Larger studies to confirm these findings are warranted.