Breakthrough of the year 2013. Cancer immunotherapy

Lipid Nanoparticles for mRNA Delivery to Enhance Cancer Immunotherapy

Messenger RNA (mRNA) is being developed by researchers as a novel drug for the treatment or prevention of many diseases. However, to enable mRNA to fully exploit its effects in vivo, researchers need to develop safer and more effective mRNA delivery systems that improve mRNA stability and enhance the ability of cells to take up and release mRNA. To date, lipid nanoparticles are promising nanodrug carriers for tumor therapy, which can significantly improve the immunotherapeutic effects of conventional drugs by modulating mRNA delivery, and have attracted widespread interest in the biomedical field. This review focuses on the delivery of mRNA by lipid nanoparticles for cancer treatment. We summarize some common tumor immunotherapy and mRNA delivery strategies, describe the clinical advantages of lipid nanoparticles for mRNA delivery, and provide an outlook on the current challenges and future developments of this technology.

Pancancer analysis of a potential gene mutation model in the prediction of immunotherapy outcomes

Background: Immune checkpoint blockade (ICB) represents a promising treatment for cancer, but predictive biomarkers are needed. We aimed to develop a cost-effective signature to predict immunotherapy benefits across cancers.

Methods: We proposed a study framework to construct the signature. Specifically, we built a multivariate Cox proportional hazards regression model with LASSO using 80% of an ICB-treated cohort (n = 1661) from MSKCC. The desired signature named SIGP was the risk score of the model and was validated in the remaining 20% of patients and an external ICB-treated cohort (n = 249) from DFCI.

Results: SIGP was based on 18 candidate genes (NOTCH3, CREBBP, RNF43, PTPRD, FAM46C, SETD2, PTPRT, TERT, TET1, ROS1, NTRK3, PAK7, BRAF, LATS1, IL7R, VHL, TP53, and STK11), and we classified patients into SIGP high (SIGP-H), SIGP low (SIGP-L) and SIGP wild type (SIGP-WT) groups according to the SIGP score. A multicohort validation demonstrated that patients in SIGP-L had significantly longer overall survival (OS) in the context of ICB therapy than those in SIGP-WT and SIGP-H (44.00 months versus 13.00 months and 14.00 months, p < 0.001 in the test set). The survival of patients grouped by SIGP in non-ICB-treated cohorts was different, and SIGP-WT performed better than the other groups. In addition, SIGP-L + TMB-L (approximately 15% of patients) had similar survivals to TMB-H, and patients with both SIGP-L and TMB-H had better survival. Further analysis on tumor-infiltrating lymphocytes demonstrated that the SIGP-L group had significantly increased abundances of CD8+ T cells.

Conclusion: Our proposed model of the SIGP signature based on 18-gene mutations has good predictive value for the clinical benefit of ICB in pancancer patients. Additional patients without TMB-H were identified by SIGP as potential candidates for ICB, and the combination of both signatures showed better performance than the single signature.

Correlation between the Immune Checkpoint Inhibitors Prognostic Index and Outcomes in Nonsmall Cell Lung Cancer: A Multicentre Analysis

OBJECTIVE

To evaluate the prognostic value of the immune checkpoint inhibitor prognostic index (ICPI), based on the albumin (ALB) and derived neutrophil-to-lymphocyte ratio (dNLR), for nonsmall cell lung cancer (NSCLC) patients receiving immune checkpoint inhibitors (ICIs).

METHODS

We conducted a multicentre retrospective study with an ICIs cohort (n = 143) and a chemotherapy control cohort (n = 84). A Cox proportional hazards regression and logistic regression model were used to find the independent risk factor for progression-free survival (PFS) and overall survival (OS) and disease control rate (DCR) in NSCLC patients. The Kaplan-Meier was used to evaluating the PFS and OS.

RESULTS

The ALB <35 g/L and dNLR >3 were correlated with worse PFS and OS for NSCLC patients receiving ICIs, respectively. The moderately high-risk ICPI had a significantly increased risk of progression (hazard ratio (HR) 1.83, 95% confidence interval (CI) 1.14-2.91; P=0.012) and of death (HR 2.33, 95% CI 1.12-4.87; P=0.024) and of nondisease control (odds ratio (OR) 3.05, 95% CI 1.19-7.83; P=0.021) and was correlated with worse PFS and 1-year survival rates (4.0 months vs. 7.2 months; P=0.001; 44.3% vs. 76.1%; P=0.001) compared with low-risk ICPI when it was characterized two groups. When ICPI was further divided into three groups, the results showed that the high-risk ICPI was correlated with worse PFS and 1-year survival rates. However, there was no difference in the chemotherapy cohort.

CONCLUSION

The ICPI was correlated with worse outcomes for NSCLC patients receiving ICIs but not for patients with chemotherapy.

In Situ Dendritic Cell Recruitment and T Cell Activation for Cancer Immunotherapy

Cancer immunotherapy has shifted the paradigm for cancer treatment in the past decade, but new immunotherapies enabling the effective treatment of solid tumors are still greatly demanded. Here we report a pore-forming hydrogel-based immunotherapy that enables simultaneous recruitment of dendritic cells and in situ activation of T cells, for reshaping the immunosuppressive tumor microenvironment and amplifying cytotoxic T lymphocyte response. The injectable pore-forming hydrogel composed of porogen-dispersed alginate network can form a macroporous structure upon injection into mice, and enables controlled release of granulocyte-macrophage colony-stimulating factor (GM-CSF), a chemoattractant for recruiting dendritic cells, and epacadostat, an inhibitor of indoleamine 2, 3-dioxygenase for activating T cells. We show that gels loaded with GM-CSF and epacadostat, after peritumoral injection, can recruit massive dendritic cells in situ and activate effector T cells in the tumor tissues, resulting in enhanced frequency and activation status of dendritic cells, reduced numbers of regulatory T (Treg) cells, and increased CD8⁺/Treg ratios in the tumor microenvironment. This hydrogel-based immunotherapy holds great promise for treating poorly-immunogenic solid tumors.

In situ release of IL-2/IL-12 from SiO2-engineered dendritic cells for synergistic immunotherapy

Herein, a synergistic therapy strategy of cytokine and dendritic cell (DC) vaccine was developed via the chemical conjugation of cytokine-loaded SiO₂ directly on the plasma membrane of DCs. Firstly, IL-2/IL-12-loaded SiO₂ was prepared and modified with MAL-PEG-NHS, and then coupled on the membrane of mature DCs through the coupling of -MAL and -SH groups. The large surface area and bimodal pores of SiO₂ endowed it with high cytokine loading capacity and entrapment efficiency (EE%), with EE_IL-2% of 95.8% and EE_IL-12% of 86.4%. SiO₂ was stably attached to the surface of DCs, and thus not internalized by mature DCs, and the SiO₂ conjugation blocked only 4.37% of the total available cell surface thiol groups. After SiO₂ attachment, the cell viability, membrane integrity and intracellular reactive oxygen species (ROS) of DCs were not affected. Furthermore, this strategy avoids the systemic toxicity of cytokines and improves the ability of DCs to target lymph nodes. IL-2 and IL-12 were only released locally around DCs, enabling the pseudo-autocrine stimulation of the transferred DCs in vivo. Moreover, the long-term anti-tumor protection in a B16 tumor model was demonstrated. This strategy is a facile and generalizable dendritic cell-based cancer immunotherapy strategy to augment bioavailability, while minimizing the side effects of cytokines.

Cancer Immunotherapy and Delivery System: An Update

With an understanding of immunity in the tumor microenvironment, immunotherapy turns out to be a powerful tool in the clinic to treat many cancers. The strategies applied in cancer immunotherapy mainly include blockade of immune checkpoints, adoptive transfer of engineered cells, such as T cells, natural killer cells, and macrophages, cytokine therapy, cancer vaccines, and oncolytic virotherapy. Many factors, such as product price, off-target side effects, immunosuppressive tumor microenvironment, and cancer cell heterogeneity, affect the treatment efficacy of immunotherapies against cancers. In addition, some treatments, such as chimeric antigen receptor (CAR) T cell therapy, are more effective in treating patients with lymphoma, leukemia, and multiple myeloma rather than solid tumors. To improve the efficacy of targeted immunotherapy and reduce off-target effects, delivery systems for immunotherapies have been developed in past decades using tools such as nanoparticles, hydrogel matrix, and implantable scaffolds. This review first summarizes the currently common immunotherapies and their limitations. It then synopsizes the relative delivery systems that can be applied to improve treatment efficacy and minimize side effects. The challenges, frontiers, and prospects for applying these delivery systems in cancer immunotherapy are also discussed. Finally, the application of these approaches in clinical trials is reviewed.

Recent advances in erythrocyte membrane-camouflaged nanoparticles for the delivery of anti-cancer therapeutics

INTRODUCTION

Red blood cell (or erythrocyte) membrane-camouflaged nanoparticles (RBC-NPs) not only have a superior circulation life and do not induce accelerated blood clearance, but also possess special functions, which offers great potential in cancer therapy.

AREAS COVERED

This review focuses on the recent advances of RBC-NPs for delivering various agents to treat cancers in light of their vital role in improving drug delivery. Meanwhile, the construction and in vivo behavior of RBC-NPs are discussed to provide an in-depth understanding of the basis of RBC-NPs for improved cancer drug delivery.

EXPERT OPINION

Although RBC-NPs are quite prospective in delivering anti-cancer therapeutics, they are still in their infancy stage and many challenges need to be overcome for successful translation into the clinic. The preparation and modification of RBC membranes, the optimization of coating methods, the scale-up production and the quality control of RBC-NPs, and the drug loading and release should be carefully considered in the clinical translation of RBC-NPs for cancer therapy.

Pancreatic tumor eradication via selective Pin1 inhibition in cancer-associated fibroblasts and T lymphocytes engagement

Cancer associated fibroblasts (CAFs) support tumors via multiple mechanisms, including maintaining the immunosuppressive tumor microenvironment and limiting infiltration of immune cells. The prolyl isomerase Pin1, whose overexpression in CAFs has not been fully profiled yet, plays critical roles in tumor initiation and progression. To decipher effects of selective Pin1 inhibition in CAFs on pancreatic cancer, here we formulate a DNA-barcoded micellular system (DMS) encapsulating the Pin1 inhibitor AG17724. DMS functionalized with CAF-targeting anti-FAP-α antibodies (antiCAFs-DMS) can selectively inhibit Pin1 in CAFs, leading to efficacious but transient tumor growth inhibition. We further integrate DNA aptamers (AptT), which can engage CD8+ T lymphocytes, to obtain a bispecific antiCAFs-DMS-AptT system. AntiCAFs-DMS-AptT inhibits tumor growth in subcutaneous and orthotopic pancreatic cancer models.

Pharmacological inhibition of the prolyl isomerase PIN1, highly expressed in cancer cells and cancer associated fibroblasts (CAF), has been proposed for cancer therapy. Here the authors report the design of a DNA-barcoded micellular system functionalized with antibodies targeting CAFs and a T cell recruiting aptamer to deliver the PIN1 inhibitor AG17724, showing antitumor response in preclinical models of pancreatic cancer.

Prognostic model of immune-related genes for patients with hepatocellular carcinoma

Background

Immune-related genes (IRGs) are closely connected to the occurrence and development of tumors. Their influence on the prognosis of patients with HCC, however, remains unclear.

Methods

From the TCGA database, we integrated 365 liver cancer tissues and 50 normal tissues to identify differential immune genes related to prognosis. Multivariate COX analysis was used to establish a new prognostic index on account of IRGs, whereby risk score = (Expression level of HSPA4*0.022) + (Expression level of PSMD14*0.042) + (Expression level of RBP2*0.019) + (Expression level of MAPT*0.197) + (Expression level of TRAF3*0.146) + (Expression level of NDRG1*(0.006) + (Expression level of NRAS*0.027) + (Expression level of IL17D*0.075).

Results

The risk score was clearly correlated with an unfavorable survival rate and with clinical characteristics. By integrating the immune-related risk score model with clinical features, a nomogram was constructed to predict the survival rate of HCC patients (1-, 3- and 5-year AUC of 0.721, 0.747 and 0.781, respectively).

Conclusion

We have established a valuable prognostic risk score for HCC patients that may be a better predictor of survival than the present method. With the risk score's strong predictive value for immune cells and functions, it may provide clinical guidance for the diagnosis and prognosis of different immunophenotypes, and provide multiple therapeutic targets for the treatment of HCC patients based on subtype-specific immune molecules.

Targeting myeloid cells with bispecific antibodies as novel immunotherapies of cancer

INTRODUCTION

Most bispecific antibody (BsAb) therapies focus on stimulating the adaptive immune system, in particular T cells, to promote tumor cell killing. Another method to promote tumor eradication is through the engagement of myeloid cells, including macrophages and neutrophils, which are abundantly present and possess intrinsic cytotoxic mechanisms for tumor cell killing, making them interesting effector cells to recruit for BsAb therapy.

AREAS COVERED

In this review, we describe the evolving knowledge of the role of macrophages and neutrophils in cancer in scientific literature. Moreover, we address the BsAbs that have been developed over the years to recruit these cell types as effector cells in immunotherapy of cancer. This includes the discussion of BsAbs that target Fc receptors (i.e. FcγR and FcαRI) to induce antibody-dependent cellular phagocytosis (ADCP) by macrophages or trogoptosis via neutrophils, as well as BsAbs that interfere with checkpoint inhibition, including the SIRPα-CD47 pathway.

EXPERT OPINION

Elucidating the complexity of macrophage and neutrophil heterogeneity in cancer may help to specifically enlist the cytotoxic ability of these cells through targeting Fc receptors and checkpoint pathways, which may further enhance anti-cancer immunity.

Genetics and Therapeutic Responses to Tumor-Infiltrating Lymphocyte Therapy of Pancreatic Cancer Patient-Derived Xenograft Models

Background and Aims

Pancreatic cancer is the seventh leading cause of cancer-related deaths worldwide. Checkpoint immunotherapy has not yet shown encouraging results in pancreatic cancer possibly because of a poor immunogenicity and/or an immune suppressive microenvironment. The aim of this study was to develop patient-derived xenograft (PDX) models, compare their genetics to the original biopsies, and assess if autologous tumor-infiltrating lymphocytes (TILs) would have antitumoral activity in pancreatic cancer.

Methods

We subcutaneously transplanted tumors from 29 patients into NOG mice to generate PDX models. We established TIL cultures and injected them into PDX mice. We analyzed histology and genetics of biopsies and PDX tumors.

Results

Tumor growths were confirmed in 11 of 29 transplantations. The PDX tumors histologically resembled their original biopsies, but because stromal cells in the PDX model tumors were from mouse, their gene expression differed from the original biopsies. Immune checkpoint ligands other than programmed death ligand-1 (PD-L1) were expressed in pancreatic cancers, but PD-L1 was rarely expressed. When it was expressed, it correlated with tumor take in PDX models. One of the 3 tumors that expressed PD-L1 was an adenosquamous cancer, and another had a mismatch repair deficiency. TILs were expanded from 6 tumors and were injected into NOG or human interleukin-2 transgenic-NOG mice carrying PDX tumors. Regression of tumors could be verified in human interleukin-2 transgenic-NOG mice in 3 of the 6 PDX models treated with autologous TILs, including the adenosquamous PDX model.

Conclusion

PDX models of pancreatic cancer can be used to learn more about tumor characteristics and biomarkers and to evaluate responses to adoptive cell therapy and combination therapies. The major benefit of the model is that modifications of T cells can be tested in an autologous humanized mouse model to gain preclinical data to support the initiation of a clinical trial.

Thermo- and Light-Responsive Polymer-Coated Magnetic Nanoparticles as Potential Drug Carriers

A series of thermo- and light-responsive copolymers of poly (N-isopropylacrylamide) (PNIPAM) and 6-[4-(4-methoxy phenyl azo)-phenoxyl-hexyl methacrylate) (AzoMA) (PNIPAM-b-PAzoMA) were synthesized via reversible addition–fragmentation chain transfer (RAFT) radical polymerization. The resulting copolymers had a narrow molecular weight distribution range of 1.06–1.24, in which Mn changed regularly with the monomer concentration. Subsequently, the diblock copolymers were successfully modified on the surface of iron oxide nanoparticles through the interaction between the chemical bonds to prepare Fe3O4@(PNIPAM-b-PAzoMA) nanoparticles. The size of fabricated nanoparticles with excellent thermo-sensitivity and photo-sensitivity was controlled at about 40–50 nm. Cell viability assays suggested that the nanoparticles showed no significant cytotoxicity and potential drug delivery in the tumor microenvironment.

Targeting the CD47-SIRPα Innate Immune Checkpoint to Potentiate Antibody Therapy in Cancer by Neutrophils

Simple Summary

Immunotherapy aims to engage various immune cells in the elimination of cancer cells. Neutrophils are the most abundant leukocytes in the circulation and have unique mechanisms by which they can kill cancer cells opsonized by antibodies. However, neutrophil effector functions are limited by the inhibitory receptor SIRPα, when it interacts with CD47. The CD47 protein is expressed on all cells in the body and acts as a ‘don’t eat me’ signal to prevent tissue damage. Cancer cells can express high levels of CD47 to circumvent tumor elimination. Thus, blocking the interaction between CD47 and SIRPα may enhance anti-tumor effects by neutrophils in the presence of tumor-targeting monoclonal antibodies. In this review, we discuss CD47-SIRPα as an innate immune checkpoint on neutrophils and explore the preliminary results of clinical trials using CD47-SIRPα blocking agents.

Abstract

In the past 25 years, a considerable number of therapeutic monoclonal antibodies (mAb) against a variety of tumor-associated antigens (TAA) have become available for the targeted treatment of hematologic and solid cancers. Such antibodies opsonize cancer cells and can trigger cytotoxic responses mediated by Fc-receptor expressing immune cells in the tumor microenvironment (TME). Although frequently ignored, neutrophils, which are abundantly present in the circulation and many cancers, have demonstrated to constitute bona fide effector cells for antibody-mediated tumor elimination in vivo. It has now also been established that neutrophils exert a unique mechanism of cytotoxicity towards antibody-opsonized tumor cells, known as trogoptosis, which involves Fc-receptor (FcR)-mediated trogocytosis of cancer cell plasma membrane leading to a lytic/necrotic type of cell death. However, neutrophils prominently express the myeloid inhibitory receptor SIRPα, which upon interaction with the ‘don’t eat me’ signal CD47 on cancer cells, limits cytotoxicity, forming a mechanism of resistance towards anti-cancer antibody therapeutics. In fact, tumor cells often overexpress CD47, thereby even more strongly restricting neutrophil-mediated tumor killing. Blocking the CD47-SIRPα interaction may therefore potentiate neutrophil-mediated antibody-dependent cellular cytotoxicity (ADCC) towards cancer cells, and various inhibitors of the CD47-SIRPα axis are now in clinical studies. Here, we review the role of neutrophils in antibody therapy in cancer and their regulation by the CD47-SIRPα innate immune checkpoint. Moreover, initial results of CD47-SIRPα blockade in clinical trials are discussed.

3D Models as a Tool to Assess the Anti-Tumor Efficacy of Therapeutic Antibodies: Advantages and Limitations

Therapeutic monoclonal antibodies (mAbs) are an emerging and very active frontier in clinical oncology, with hundred molecules currently in use or being tested. These treatments have already revolutionized clinical outcomes in both solid and hematological malignancies. However, identifying patients who are most likely to benefit from mAbs treatment is currently challenging and limiting the impact of such therapies. To overcome this issue, and to fulfill the expectations of mAbs therapies, it is urgently required to develop proper culture models capable of faithfully reproducing the interactions between tumor and its surrounding native microenvironment (TME). Three-dimensional (3D) models which allow the assessment of the impact of drugs on tumors within its TME in a patient-specific context are promising avenues to progressively fill the gap between conventional 2D cultures and animal models, substantially contributing to the achievement of personalized medicine. This review aims to give a brief overview of the currently available 3D models, together with their specific exploitation for therapeutic mAbs testing, underlying advantages and current limitations to a broader use in preclinical oncology.

PD-L1 regulates cell proliferation and apoptosis in acute myeloid leukemia by activating PI3K-AKT signaling pathway

As immune checkpoint inhibitors (ICIs) continue to advance, more evidence has emerged that anti-PD-1/PD-L1 immunotherapy is an effective treatment against cancers. Known as the programmed death ligand-1 (PD-L1), this co-inhibitory ligand contributes to T cell exhaustion by interacting with programmed death-1 (PD-1) receptor. However, cancer-intrinsic signaling pathways of the PD-L1 molecule are not well elucidated. Therefore, the present study aimed to evaluate the regulatory network of PD-L1 and lay the basis of successful use of anti-PD-L1 immunotherapy in acute myeloid leukemia (AML). Data for AML patients were extracted from TCGA and GTEx databases. The downstream signaling pathways of PD-L1 were identified via Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. The key PD-L1 related genes were selected by weighted gene co-expression network analysis (WGCNA), MCC algorithm and Molecular Complex Detection (MCODE). The CCK-8 assay was used to assess cell proliferation. Flow cytometry was used to determine cell apoptosis and cell cycle. Western blotting was used to identify the expression of the PI3K-AKT signaling pathway. PD-L1 was shown to be elevated in AML patients when compared with the control group, and high PD-L1 expression was associated with poor overall survival rate. The ECM-receptor interaction, as well as the PI3K-AKT signaling pathway, were important PD-L1 downstream pathways. All three analyses found eight genes (ITGA2B, ITGB3, COL6A5, COL6A6, PF4, NMU, AGTR1, F2RL3) to be significantly associated with PD-L1. Knockdown of PD-L1 inhibited AML cell proliferation, induced cell apoptosis and G2/M cell cycle arrest. Importantly, PD-L1 knockdown reduced the expression of PI3K and p-AKT, but PD-L1 overexpression increased their expression. The current study elucidates the main regulatory network and downstream targets of PD-L1 in AML, assisting in the understanding of the underlying mechanism of anti-PD-1/PD-L1 immunotherapy and paving the way for clinical application of ICIs in AML.

Targeting CD47 as a Novel Immunotherapy for Breast Cancer

Nowadays, breast cancer has become the most common cancer worldwide with a high mortality rate. Immune checkpoint blockade holds great promise in tumor‐targeted therapy, and CD47 blockade as one immune therapy is undergoing various preclinical studies and clinical trials to demonstrate its safety and efficacy in breast cancer. In this review, we summarized different therapeutic mechanisms targeting CD47 and its prognostic role and therapeutic value in breast cancer.

A Novel Prognostic Signature Revealed the Interaction of Immune Cells in Tumor Microenvironment Based on Single-Cell RNA Sequencing for Lung Adenocarcinoma

Background

The tumor immune microenvironment (TIME) played an important role in immunotherapy prognosis and treatment response. Immune cells constitute a large part of the tumor microenvironment and regulate tumor progression. Our research is dedicated to studying the infiltrating immune cell in lung adenocarcinoma (LUAD) and seeking potential targets.

Methods

The scRNA-seq data were collected from our FDZSH and two public datasets. The code for cell-type mapping algorithms was downloaded from the CIBERSORTx portal. The bioinformatics data of LUAD patients could be approached from The Cancer Genome Atlas (TCGA) portal. Weighted gene coexpression network analysis (WGCNA) and least absolute shrinkage and selection operator (LASSO) analyses were performed to construct a risk model. TIMER2 and TIDE helped with the immune infiltration estimation, while PROGENy helped the cancer-related pathways' enrichment analysis. GSE31210 dataset and IMVigor ICB therapy cohort validated our findings as the external validation datasets.

Results

We clustered the scRNA-seq dataset (integrating our FDZSH datasets and other public datasets) into 23 subpopulations. After curated cell annotation, we implemented Cibersort and WGCNA analysis to anchor the brown module and natural killer cell cluster1 due to the most relationship with tumor trait. The overlap of the brown module gene, natural killer cell signature, and DEGs of tumor and adjacent normal samples was screened by LASSO Cox regression. The obtained 5-gene risk model showed an excellent prognostic performance in the validation dataset. Furthermore, there was a correlation between risk score and tumor-infiltrating immune cells and tumor genomics abnormity. Patients with higher risk scores had a significantly lower immunotherapy response rate.

Conclusion

Our observations implied that immune cells played a pivotal role in TIME and established a 5-gene signature (including IDH2, ADRB2, SFTPC, CCDC69, and CCND2) on the basement of nature killer markers targeted by WGCNA analysis. The significance of clinical outcome and immunotherapy response prediction was validated robustly.

Validation of the Optimum Timing of Assessment of Tumor Infiltrating Lymphocytes During Preoperative Chemotherapy for Breast Cancer

BACKGROUND/AIM

Tumor microenvironment (TME) assessment is considered to play an important role in the prediction of prognosis and therapeutic response following breast cancer treatment. No consensus has been reached regarding evaluation methods despite reports on the utilization of tumor-infiltrating lymphocytes (TILs) for immune TME (iTME) monitoring. Optimum timing of iTME assessment has not yet been established.

PATIENTS AND METHODS

Two hundred thirty-nine patients were treated with neoadjuvant chemotherapy (NAC). During the period from diagnostic needle biopsy to NAC initiation for breast cancer, the optimal evaluation timing was examined using a receiver operating characteristic (ROC) curve analysis.

RESULTS

A significant correlation between TILs and pathological complete response (pCR) was only observed in the short-term group (≤35 days) (p=0.033). Prognostic analysis revealed that in the short-term group, patients with high TIL levels had a significantly better survival prognosis relative to those with low TIL levels (>35 days) [disease-free survival (DFS): p=0.001, overall survival (OS): p=0.021]. TILs were identified as an independent factor affecting DFS in a multivariate analysis (p=0.008, hazard ratio=0.130).

CONCLUSION

TIL assessment during NAC for breast cancer is a prognostic predictor only when performed at ≤35 days before NAC initiation.

Cancer pharmacomicrobiomics: targeting microbiota to optimise cancer therapy outcomes

Despite the promising advances in novel cancer therapy such as immune checkpoint inhibitors (ICIs), limitations including therapeutic resistance and toxicity remain. In recent years, the relationship between gut microbiota and cancer has been extensively studied. Accumulating evidence reveals the role of microbiota in defining cancer therapeutic efficacy and toxicity. Unlike host genetics, microbiota can be easily modified via multiple strategies, including faecal microbiota transplantation (FMT), probiotics and antibiotics. Preclinical studies have identified the mechanisms on how microbes influence cancer treatment outcomes. Clinical trials have also demonstrated the potential of microbiota modulation in cancer treatments. Herein, we review the mechanistic insights of gut microbial interactions with chemotherapy and ICIs, particularly focusing on the interplay between gut bacteria and the pharmacokinetics (eg, metabolism, enzymatic degradation) or pharmacodynamics (eg, immunomodulation) of cancer treatment. The translational potential of basic findings in clinical settings is then explored, including using microbes as predictive biomarkers and microbial modulation by antibiotics, probiotics, prebiotics, dietary modulations and FMT. We further discuss the current limitations of gut microbiota modulation in patients with cancer and suggest essential directions for future study. In the era of personalised medicine, it is crucial to understand the microbiota and its interactions with cancer. Manipulating the gut microbiota to augment cancer therapeutic responses can provide new insights into cancer treatment.

Immunogenic Cell Death and Role of Nanomaterials Serving as Therapeutic Vaccine for Personalized Cancer Immunotherapy

Immunogenic cell death (ICD) is a rapidly growing research area representing one of the emerging therapeutic strategies of cancer immunotherapy. ICD is an umbrella term covering several cell death modalities including apoptosis, necroptosis, ferroptosis and pyroptosis, and is the product of a balanced combination of adjuvanticity (damage-associated molecular patterns and chemokines/cytokines) and antigenicity (tumor associated antigens). Only a limited number of anti-cancer therapies are available to induce ICD in experimental cancer therapies and even much less is available for clinical use. To overcome this limitation, nanomaterials can be used to increase the immunogenicity of cancer cells killed by anti-cancer therapy, which in themselves are not necessarily immunogenic. In this review, we outline the current state of knowledge of ICD modalities and discuss achievements in using nanomaterials to increase the immunogenicity of dying cancer cells. The emerging trends in modulating the immunogenicity of dying cancer cells in experimental and translational cancer therapies and the challenges facing them are described. In conclusion, nanomaterials are expected to drive further progress in their use to increase efficacy of anti-cancer therapy based on ICD induction and in the future, it is necessary to validate these strategies in clinical settings, which will be a challenging research area.

Identification of Alternative Splicing-Related Genes CYB561 and FOLH1 in the Tumor-Immune Microenvironment for Endometrial Cancer Based on TCGA Data Analysis

Background: Advanced and recurrent endometrial cancer EC remains controversial. Immunotherapy will play a landmark role in cancer treatment, and alternative splicing (AS) of messenger RNA (mRNA) may offer the potential of a broadened target space.

Methods: We downloaded the clinical information and mRNA expression profiles from The Cancer Genome Atlas (TCGA) database. Hub genes were extracted from 11 AS-related genes to analyze the correlation between clinical parameters and the tumor-immune microenvironment. We also analyzed the correlations between the copy numbers, gene expressions of hub genes, and immune cells. The correlation between the risk score and the six most important checkpoint genes was also investigated. The ESTIMATE algorithm was finally performed on each EC sample based on the high- and low-risk groups.

Results: The risk score was a reliable and stable independent risk predictor in the Uterine Corpus Endometrial Carcinoma (UCEC) cohort. CYB561|42921|AP and FOLH1|15817|ES were extracted. The expression of CYB561 and FOLH1 decreased gradually with the increased grade and International Federation of Gynecology and Obstetrics (FIGO) stage (p &lt; 0.05). Gene copy number changes in CYB561 and FOLH1 led to the deletion number of myeloid DC cells and T cell CD8+. Low expression of both CYB561 and FOLH1 was associated with poor prognosis (p &lt; 0.001). The checkpoint genes, CTLA-4 and PDCD1, exhibited a negative correlation with the risk score of AS in UCEC.

Conclusion: AS-related gene signatures were related to the immune-tumor microenvironment and prognosis. These outcomes were significant for studying EC’s immune-related mechanisms and exploring novel prognostic predictors and precise therapy methods.

Research Trends in Immune Checkpoint Blockade for Melanoma: Visualization and Bibliometric Analysis

BACKGROUND

Melanoma is one of the most life-threatening skin cancers; immune checkpoint blockade is widely used in the treatment of melanoma because of its remarkable efficacy.

OBJECTIVE

This study aimed to conduct a comprehensive bibliometric analysis of research conducted in recent decades on immune checkpoint blockade for melanoma, while exploring research trends and public interest in this topic.

METHODS

We summarized the articles in the Web of Science Core Collection on immune checkpoint blockade for melanoma in each year from 1999 to 2020. The R package bibliometrix was used for data extraction and visualization of the distribution of publication year and the top 10 core authors. Keyword citation burst analysis and cocitation networks were calculated with CiteSpace. A Gunn online world map was used to evaluate distribution by country and region. Ranking was performed using the Standard Competition Ranking method. Coauthorship analysis and co-occurrence were analyzed and visualized with VOSviewer.

RESULTS

After removing duplicates, a total of 9169 publications were included. The distribution of publications by year showed that the number of publications rose sharply from 2015 onwards and either reached a peak in 2020 or has yet to reach a peak. The geographical distribution indicated that there was a large gap between the number of publications in the United States and other countries. The coauthorship analysis showed that the 149 top institutions were grouped into 8 clusters, each covering approximately a single country, suggesting that international cooperation among institutions should be strengthened. The core author extraction revealed changes in the most prolific authors. The keyword analysis revealed clustering and top citation bursts. The cocitation analysis of references from 2010 to 2020 revealed the number of citations and the centrality of the top articles.

CONCLUSIONS

This study revealed trends in research and public interest in immune checkpoint blockade for melanoma. Our findings suggest that the field is growing rapidly, has several core authors, and that the United States is taking the lead position. Moreover, cooperation between countries should be strengthened, and future research hot spots might focus on deeper exploration of drug mechanisms, prediction of treatment efficacy, prediction of adverse events, and new modes of administration, such as combination therapy, which may pave the way for further research.

Advanced Therapy Medicinal Products and the Changing Role of Academia

Academic institutions coin the ATMP landscape but do not possess an industry-like capacity to vigorously pursue the full developmental pathway to marketing authorization. At the same time, industry has fostered clinical trials with ATMPs, brought the first products to marketing authorization, and defined novel modes of interaction with academia. A regulatory niche for local manufacturing of ATMPs within an academic institution had been foreseen in Regulation (EU) 1394/2007 under the term "Hospital Exemption" but remained ill-defined. Manufacture in close proximity to the patient is difficult to accomplish, as "point of care" systems for the manufacture of ATMPs have encountered regulatory challenges hovering between process and product. The efforts and costs for the development of ATMPs continue to be dramatically underestimated, and few academic centers were persistent enough to invest in the GMP infrastructure needed and to recruit personnel trained in ATMP development. As a consequence, the contribution by hospitals to ATMP development has shifted from the finished ATMP toward the procurement of starting materials, selected manufacturing steps, storage of the product, clinical application, and participation in clinical trials. As the development and use of cell-based therapies and ATMPs continue to attract and challenge clinicians and scientists, this review aims to discuss logistical, financial, and regulatory issues that might contribute to the changing role of Academia in ATMP development, with an outlook into possible developments in the future and proposals for ways to reshape the academic environment under the auspices of what might truly have been meant by the hospital exemption clause.

Charting roadmaps towards novel and safe synergistic immunotherapy combinations

Checkpoint inhibitor-based cancer immunotherapy is often combined in the clinic with other immunotherapy strategies, targeted therapies, chemotherapy or standard-of-care treatments to achieve superior therapeutic efficacy. The large number of immunotherapy combinations that are currently undergoing clinical testing necessitate the establishment of faithful criteria to prioritize optimal combinations with evidence of synergy, to determine their safety and optimal sequence of administration and to identify biomarkers of therapy resistance and response. In this review, we focus on recent developments in immunotherapy combinations and reflect on how combinations should be optimized to maximize the impact of immunotherapy in clinical oncology.

Local scaffold-assisted delivery of immunotherapeutic agents for improved cancer immunotherapy

Cancer immunotherapy, which reprograms a patient's own immune system to eradicate cancer cells, has been demonstrated as a promising therapeutic strategy clinically. Immune checkpoint blockade (ICB) therapies, cytokine therapies, cancer vaccines, and chimeric antigen receptor (CAR) T cell therapies utilize immunotherapy techniques to relieve tumor immune suppression and/or activate cellular immune responses to suppress tumor growth, metastasis and recurrence. However, systemic administration is often hampered by limited drug efficacy and adverse side effects due to nonspecific tissue distribution of immunotherapeutic agents. Advancements in local scaffold-based delivery systems facilitate a controlled release of therapeutic agents into specific tissue sites through creating a local drug reservoir, providing a potent strategy to overcome previous immunotherapy limitations by improving site-specific efficacy and minimizing systemic toxicity. In this review, we summarized recent advances in local scaffold-assisted delivery of immunotherapeutic agents to reeducate the immune system, aiming to amplify anticancer efficacy and minimize immune-related adverse events. Additionally, the challenges and future perspectives of local scaffold-assisted cancer immunotherapy for clinical translation and applications are discussed.

Nanoplatform Self-Assembly from Small Molecules of Porphyrin Derivatives for NIR-II Fluorescence Imaging Guided Photothermal-Immunotherapy

Combinatorial photothermal and immunotherapy have demonstrated great potential to remove primary tumors, suppress metastases, and prevent tumor recurrence. However, this strategy still confronts patients with many limitations, such as complex components, sophisticated construction, and inadequate therapeutic efficacy. In this work, small molecules of porphyrin derivatives (PPor) which can self-assemble into monodispersed nanoparticles without supplement of any other ingredients or surfactants are developed. The formed PPor nanoparticles (PPor NPs) exhibit highly photothermal conversion efficiency of 70% and NIR-II luminous abilities originate from the strong intramolecular charge transfer (ICT) effect of D-A structure under 808 nm laser irradiation, thus achieving NIR-II fluorescence imaging guided photothermal therapy (PTT) against primary tumors with a high cure rate. More importantly, tumor-associated antigens (TAAs), together with damage-associated molecular patterns (DAMPs) released from PTT-treated cancer cells, are proved to elicit immune responses to some degree. After combination with programmed cell death-1 (PD-1) antibodies, a robust systematic antitumor immunity is generated to restrain both primary and abscopal tumors growth, prolong survival, and prevent pulmonary metastasis on an aggressive 4T1 murine breast tumor model. Thus, this study provides a promising therapeutic paradigm with porphyrin derivatives nano-assembly as phototheranostic agents for the treatment of aggressive tumors with high efficiency.

Insight of pancreatic cancer: recommendations for improving its therapeutic efficacy in the next decade

Pancreatic cancer is one of the most malignant digestive system tumors. The effectiveness of pancreatic cancer treatment is still dismal, and the 5-year survival rate is only about 10%. Further improving the diagnosis and treatment of pancreatic cancer is the top priority of oncology research and clinical practice. Based on the existing clinical and scientific research experience, the review provides insight into the hotspots and future directions for pancreatic cancer, which focuses on early detection, early diagnosis, molecular typing and precise treatment, new drug development and regimen combination, immunotherapy, database development, model establishment, surgical technology and strategy change, as well as innovation of traditional Chinese medicine and breakthrough of treatment concept.

A Bayesian phase I/II biomarker-based design for identifying subgroup-specific optimal dose for immunotherapy

Immunotherapy is an innovative treatment that enlists the patient's immune system to battle tumors. The optimal dose for treating patients with an immunotherapeutic agent may differ according to their biomarker status. In this article, we propose a biomarker-based phase I/II dose-finding design for identifying subgroup-specific optimal dose for immunotherapy (BSOI) that jointly models the immune response, toxicity, and efficacy outcomes. We propose parsimonious yet flexible models to borrow information across different types of outcomes and subgroups. We quantify the desirability of the dose using a utility function and adopt a two-stage dose-finding algorithm to find the optimal dose for each subgroup. Simulation studies show that the BSOI design has desirable operating characteristics in selecting the subgroup-specific optimal doses and allocating patients to those optimal doses, and outperforms conventional designs.

From Tumor Cells to Endothelium and Gut Microbiome: A Complex Interaction Favoring the Metastasis Cascade

Metastasis is a complicated process through which tumor cells disseminate to distant organs and adapt to novel tumor microenvironments. This multi-step cascade relies on the accumulation of genetic and epigenetic alterations within the tumor cells as well as the surrounding non-tumor stromal cells. Endothelial cells constitute a major player in promoting metastasis formation either by inducing the growth of tumor cells or by directing them towards dissemination in the blood or lymph. In fact, the direct and indirect interactions between tumor and endothelial cells were shown to activate several mechanisms allowing cancer cells’ invasion and extravasation. On the other side, gastrointestinal cancer development was shown to be associated with the disruption of the gut microbiome. While several proposed mechanisms have been investigated in this regard, gut and tumor-associated microbiota were shown to impact the gut endothelial barrier, increasing the dissemination of bacteria through the systemic circulation. This bacterial dislocation allows the formation of an inflammatory premetastatic niche in the distant organs promoting the metastatic cascade of primary tumors. In this review, we discuss the role of the endothelial cells in the metastatic cascade of tumors. We will focus on the role of the gut vascular barrier in the regulation metastasis. We will also discuss the interaction between this vascular barrier and the gut microbiota enhancing the process of metastasis. In addition, we will try to elucidate the different mechanisms through which this bacterial dislocation prepares the favorable metastatic niche at distant organs allowing the dissemination and successful deposition of tumor cells in the new microenvironments. Finally, and given the promising results of the studies combining immune checkpoint inhibitors with either microbiota alterations or anti-angiogenic therapy in many types of cancer, we will elaborate in this review the complex interaction between these 3 factors and their possible therapeutic combination to optimize response to treatment.

What will (and should) be improved in CAR immunotherapy?

Chimeric antigen receptor (CAR) is probably one of the most successful proposals for cancer treatment, especially hematological diseases for which several Advanced Therapies Medicinal Products (ATMP) have been approved worldwide by drug agencies. But, despite this unprecedented success in the oncology and cell/gene therapy fields, there are a lot of aspects that could (and should) be improved in the multiple aspects that involve this complex therapy: from the design of the chimeric molecule to the clinical protocols of use of the engineered T-cells, including even the regulatory rules that they are currently restricting the development of these hopeful therapies. In this chapter, we will try to summarize the main aspects that can (and probably should) be improved for the expansion of immunotherapy with CAR proposals beyond onco-hematology.

Single-Cell RNA-Seq and Bulk RNA-Seq Reveal Intratumoral Heterogeneity and Tumor Microenvironment Characteristics in Diffuse Large B-Cell Lymphoma

Background: Diffuse large B-cell lymphoma (DLBCL) is the most common histologic subtype of non-Hodgkin’s lymphoma (NHL) with highly heterogeneous genetic and phenotypic features. Therefore, a comprehensive understanding of cellular diversity and intratumoral heterogeneity is essential to elucidate the mechanisms driving DLBCL progression and to develop new therapeutic approaches.

Methods: We analyzed single-cell transcriptomic data from 2 reactive lymph node tissue samples and 2 DLBCL lymph node biopsy tissue samples to explore the transcriptomic landscape of DLBCL. In addition, we constructed a prognostic model based on the genes obtained from differential analysis.

Results: Based on gene expression profiles at the single cell level, we identified and characterized different subpopulations of malignant and immune cells. Malignant cells exhibited a high degree of inter-tumor heterogeneity. Tumor-infiltrating regulatory CD4⁺ T cells showed highly immunosuppressive properties and exhausted cytotoxic CD8⁺ T cells were highly expressed with markers of exhaustion. Cell communication analysis identified complex interactions between malignant cells and other cell subpopulations. In addition, the prognostic model we constructed allows for monitoring the prognosis of DLBCL patients.

Conclusion: This study provides an in-depth dissection of the transcriptional features of malignant B cells and tumor microenvironment (TME) in DLBCL and provides new insights into the tumor heterogeneity of DLBCL.

CD123 and More: How to Target the Cell Surface of Blastic Plasmacytoid Dendritic Cell Neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive leukemia derived from plasmacytoid dendritic cells (pDCs). It is associated with a remarkably poor prognosis and unmet need for better therapies. Recently, the first-in-class CD123-targeting therapy, tagraxofusp, was approved for treatment of BPDCN. Other CD123-targeting strategies are in development, including bispecific antibodies and combination approaches with tagraxofusp and other novel agents. In other blood cancers, adoptive T-cell therapy using chimeric antigen receptor (CAR)-modified T cells represents a promising new avenue in immunotherapy, showing durable remissions in some relapsed hematologic malignancies. Here, we report on novel and innovative therapies in development to target surface molecules in BPDCN currently in clinical trials or in preclinical stages. We also discuss new cell surface targets that may have implications for future BPDCN treatment.

An in silico Model of T Cell Infiltration Dynamics Based on an Advanced in vitro System to Enhance Preclinical Decision Making in Cancer Immunotherapy

Cancer immunotherapy often involves the use of engineered molecules to selectively bind and activate T cells located within tumour tissue. Fundamental to the success of such treatments is the presence or recruitment of T cells localised within the tumour microenvironment. Advanced organ-on-a-chip systems provide an in vitro setting in which to investigate how novel molecules influence the spatiotemporal dynamics of T cell infiltration into tissue, both in the context of anti-tumour efficacy and off-tumour toxicity. While highly promising, the complexity of these systems is such that mathematical modelling plays a crucial role in the quantitative evaluation of experimental results and maximising the mechanistic insight derived. We develop a mechanistic, mathematical model of a novel microphysiological in vitro platform that recapitulates T cell infiltration into epithelial tissue, which may be normal or transformed. The mathematical model describes the spatiotemporal dynamics of infiltrating T cells in response to chemotactic cytokine signalling. We integrate the model with dynamic imaging data to optimise key model parameters. The mathematical model demonstrates a good fit to the observed experimental data and accurately describes the distribution of infiltrating T cells. This model is designed to complement the in vitro system; with the potential to elucidate complex biological mechanisms, including the mode of action of novel therapies and the drivers of safety events, and, ultimately, improve the efficacy-safety profile of T cell-targeted cancer immunotherapies.

The interplay between anticancer challenges and the microbial communities from the gut

Cancer being an increasing burden on human health, the use of anticancer drugs has risen over the last decades. The physiological effects of these drugs are not only perceived by the host's cells but also by the microbial cells it harbors as commensals, notably the gut microbiota. Since the early '50 s, the cytotoxicity of anticancer chemotherapy was evaluated on bacteria revealing some antimicrobial activities that result in an established perturbation of the gut microbiota. This perturbation can affect the host's health through dysbiosis, which can lead to multiple complications, but has also been shown to have a direct effect on the treatment efficiency.We, therefore, conducted a review of literature focusing on this triangular relationship involving the microbial communities from the gut, the host's disease, and the anticancer treatment. We focused specifically on the antimicrobial effects of anticancer chemotherapy, their impact on mutagenesis in bacteria, and the perspectives of using bacteria-based tools to help in the diagnostic and treatment of cancer.

A nanovaccine for antigen self-presentation and immunosuppression reversal as a personalized cancer immunotherapy strategy

The strategy of combining a vaccine with immune checkpoint inhibitors has been widely investigated in cancer management, but the complete response rate for this strategy is still unresolved. We describe a genetically engineered cell membrane nanovesicle that integrates antigen self-presentation and immunosuppression reversal (ASPIRE) for cancer immunotherapy. The ASPIRE nanovaccine is derived from recombinant adenovirus-infected dendritic cells in which specific peptide-major histocompatibility complex class I (pMHC-I), anti-PD1 antibody and B7 co-stimulatory molecules are simultaneously anchored by a programmed process. ASPIRE can markedly improve antigen delivery to lymphoid organs and generate broad-spectrum T-cell responses that eliminate established tumours. This work presents a powerful vaccine formula that can directly activate both native T cells and exhausted T cells, and suggests a general strategy for personalized cancer immunotherapy.

Potent suppression of neuroendocrine tumors and gastrointestinal cancers by CDH17CAR T cells without toxicity to normal tissues

Gastrointestinal cancers (GICs) and neuroendocrine tumors (NETs) are often refractory to therapy after metastasis. Adoptive cell therapy using chimeric antigen receptor (CAR) T cells, though remarkably efficacious for treating leukemia, is yet to be developed for solid tumors such as GICs and NETs. Here we isolated a llama-derived nanobody, VHH1, and found that it bound cell surface adhesion protein CDH17 upregulated in GICs and NETs. VHH1-CAR T cells (CDH17CARTs) killed both human and mouse tumor cells in a CDH17-dependent manner. CDH17CARTs eradicated CDH17-expressing NETs and gastric, pancreatic and colorectal cancers in either tumor xenograft or autochthonous mouse models. Notably, CDH17CARTs do not attack normal intestinal epithelial cells, which also express CDH17, to cause toxicity, likely because CDH17 is localized only at the tight junction between normal intestinal epithelial cells. Thus, CDH17 represents a class of previously unappreciated tumor-associated antigens that is 'masked' in healthy tissues from attack by CAR T cells for developing safer cancer immunotherapy.

Genetic Engineering and Enrichment of Human NK Cells for CAR-Enhanced Immunotherapy of Hematological Malignancies

The great clinical success of chimeric antigen receptor (CAR) T cells has unlocked new levels of immunotherapy for hematological malignancies. Genetically modifying natural killer (NK) cells as alternative CAR immune effector cells is also highly promising, as NK cells can be transplanted across HLA barriers without causing graft-versus-host disease. Therefore, off-the-shelf usage of CAR NK cell products might allow to widely expand the clinical indications and to limit the costs of treatment per patient. However, in contrast to T cells, manufacturing suitable CAR NK cell products is challenging, as standard techniques for genetically engineering NK cells are still being defined. In this study, we have established optimal lentiviral transduction of primary human NK cells by systematically testing different internal promoters for lentiviral CAR vectors and comparing lentiviral pseudotypes and viral entry enhancers. We have additionally modified CAR constructs recognizing standard target antigens for acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) therapy—CD19, CD33, and CD123—to harbor a CD34-derived hinge region that allows efficient detection of transduced NK cells in vitro and in vivo and also facilitates CD34 microbead-assisted selection of CAR NK cell products to >95% purity for potential clinical usage. Importantly, as most leukemic blasts are a priori immunogenic for activated primary human NK cells, we developed an in vitro system that blocks the activating receptors NKG2D, DNAM-1, NKp30, NKp44, NKp46, and NKp80 on these cells and therefore allows systematic testing of the specific killing of CAR NK cells against ALL and AML cell lines and primary AML blasts. Finally, we evaluated in an ALL xenotransplantation model in NOD/SCID-gamma (NSG) mice whether human CD19 CAR NK cells directed against the CD19+ blasts are relying on soluble or membrane-bound IL15 production for NK cell persistence and also in vivo leukemia control. Hence, our study provides important insights into the generation of pure and highly active allogeneic CAR NK cells, thereby advancing adoptive cellular immunotherapy with CAR NK cells for human malignancies further.

T-Cell Heterogeneity in Baseline Tumor Samples: Implications for Early Clinical Trial Design and Analysis

Background

In early stage clinical trials, changes to levels of tumor infiltrating lymphocytes (TILs) in the tumor microenvironment (TME) are critical biomarkers of the mechanism of action of novel immunotherapies. However, baseline heterogeneity of tumor samples, both between and within patients, and the resultant impact on the validity of clinical trial data is not well defined. Here we identify and quantify the impact of baseline variables on the heterogeneity of FoxP3+ and proliferating CD8+ T-cells levels (MKi67+CD8A+) in the TME both between and within patients for the purpose of informing clinical trial design and analysis.

Methods

We compared levels of FoxP3+ and MKi67+CD8+ cell densities (counts/mm2) from >1000 baseline tumor samples from clinical trials and commercially available sources. Using multivariate hierarchical regression techniques, we investigated whether inter-person heterogeneity of activated or regulatory T-cells could be attributed to baseline characteristics including demographics, indication, lesion type, tissue of excision, biopsy method, prior cancer treatment, and tissue type i.e., "fresh" or "archival" status. We also sought to characterize within-patient heterogeneity by lesion type and tissue type.

Results

Prior cancer treatment with hormone therapy or chemotherapy that induces immunogenic cell death may alter the TME. Archival tissue is an unreliable substitute for fresh tissue for determining baseline TIL levels. Baseline and on treatment biopsies should be matched by lesion type to avoid bias.