Proteogenomic Analysis of Human Colon Cancer Reveals New Therapeutic Opportunities.

We performed the first proteogenomic study on a prospectively collected colon cancer cohort. Comparative proteomic and phosphoproteomic analysis of paired tumor and normal adjacent tissues produced a catalog of colon cancer-associated proteins and phosphosites, including known and putative new biomarkers, drug targets, and cancer/testis antigens. Proteogenomic integration not only prioritized genomically inferred targets, such as copy-number drivers and mutation-derived neoantigens, but also yielded novel findings. Phosphoproteomics data associated Rb phosphorylation with increased proliferation and decreased apoptosis in colon cancer, which explains why this classical tumor suppressor is amplified in colon tumors and suggests a rationale for targeting Rb phosphorylation in colon cancer. Proteomics identified an association between decreased CD8 T cell infiltration and increased glycolysis in microsatellite instability-high (MSI-H) tumors, suggesting glycolysis as a potential target to overcome the resistance of MSI-H tumors to immune checkpoint blockade. Proteogenomics presents new avenues for biological discoveries and therapeutic development.

Identification of CD160-TM as a tumor target on triple negative breast cancers: possible therapeutic applications.

BACKGROUND: Despite major therapeutic advances, triple-negative breast cancer (TNBC) still presents a worth prognosis than hormone receptors-positive breast cancers. One major issue relies in the molecular and mutational heterogeneity of TNBC subtypes that is reinforced by the absence of reliable tumor-antigen that could serve as a specific target to further promote efficient tumor cell recognition and depletion. CD160 is a receptor mainly expressed by NK lymphocytes and presenting two isoforms, namely the GPI-anchored form (CD160-GPI) and the transmembrane isoform (CD160-TM). While CD160-GPI is constitutively expressed on resting cells and involved in the generation of NK cells' cytotoxic activity, CD160-TM is neo-synthesized upon activation and promotes the amplification of NK cells' killing ability. METHODS: CD160 expression was assessed by immunohistochemistry (IHC) and flow cytometry on TNBC patient biopsies or cell lines, respectively. Antibody (Ab)-mediated tumor depletion was tested in vitro by performing antibody-dependent cell cytotoxicity (ADCC) and phagocytosis (ADCP) assays, and in vivo on a TNBC mouse model. RESULTS: Preliminary data obtained by IHC on TNBC patients' tumor biopsies revealed an unconventional expression of CD160 by TNBC tumor cells. By using a specific but conformation-dependent anti-CD160-TM Ab, we established that CD160-TM, but not CD160-GPI, was expressed by TNBC tumor cells. A conformation-independent anti-CD160-TM mAb (22B12; muIgG2a isotype) was generated and selected according to pre-defined specificity and functional criterions. In vitro functional assays demonstrated that ADCC and ADCP could be induced in the presence of 22B12, resulting in TNBC cell line apoptosis. The ability of 22B12 to exert an in vivo anti-tumor activity was also demonstrated on a TNBC murine model. CONCLUSIONS: Our data identify CD160-TM as a tumor marker for TNBC and provide a rational for the use of anti-CD160-TM antibodies as therapeutic tools in this tumor context.

Arginine-linked HPV-associated E7 displaying bacteria-derived outer membrane vesicles as a potent antigen-specific cancer vaccine.

BACKGROUND: Bacteria-based cancer therapy have demonstrated innovative strategies to combat tumors. Recent studies have focused on gram-negative bacterial outer membrane vesicles (OMVs) as a novel cancer immunotherapy strategy due to its intrinsic properties as a versatile carrier. METHOD: Here, we developed an Human Papillomavirus (HPV)-associated E7 antigen displaying Salmonella-derived OMV vaccine, utilizing a Poly(L-arginine) cell penetrating peptide (CPP) to enhance HPV16 E7 (aa49-67) H-2 Db and OMV affinity, termed SOMV-9RE7. RESULTS: Due to OMV's intrinsic immunogenic properties, SOMV-9RE7 effectively activates adaptive immunity through antigen-presenting cell uptake and antigen cross-presentation. Vaccination of engineered OMVs shows immediate tumor suppression and recruitment of infiltrating tumor-reactive immune cells. CONCLUSION: The simplicity of the arginine coating strategy boasts the versatility of immuno-stimulating OMVs that can be broadly implemented to personalized bacterial immunotherapeutic applications.

The recent advancement of TCR-T cell therapies for cancer treatment.

Adoptive cell therapies involve infusing engineered immune cells into cancer patients to recognize and eliminate tumor cells. Adoptive cell therapy, as a form of living drug, has undergone explosive growth over the past decade. The recognition of tumor antigens by the T-cell receptor (TCR) is one of the natural mechanisms that the immune system used to eliminate tumor cells. TCR-T cell therapy, which involves introducing exogenous TCRs into patients' T cells, is a novel cell therapy strategy. TCR-T cell therapy can target the entire proteome of cancer cells. Engineering T cells with exogenous TCRs to help patients combat cancer has achieved success in clinical trials, particularly in treating solid tumors. In this review, we examine the progress of TCR-T cell therapy over the past five years. This includes the discovery of new tumor antigens, protein engineering techniques for TCR, reprogramming strategies for TCR-T cell therapy, clinical studies on TCR-T cell therapy, and the advancement of TCR-T cell therapy in China. We also propose several potential directions for the future development of TCR-T cell therapy.

CAR T cells: engineered immune cells to treat brain cancers and beyond.

Malignant brain tumors rank among the most challenging type of malignancies to manage. The current treatment protocol commonly entails surgery followed by radiotherapy and/or chemotherapy, however, the median patient survival rate is poor. Recent developments in immunotherapy for a variety of tumor types spark optimism that immunological strategies may help patients with brain cancer. Chimeric antigen receptor (CAR) T cells exploit the tumor-targeting specificity of antibodies or receptor ligands to direct the cytolytic capacity of T cells. Several molecules have been discovered as potential targets for immunotherapy-based targeting, including but not limited to EGFRvIII, IL13Rα2, and HER2. The outstanding clinical responses to CAR T cell-based treatments in patients with hematological malignancies have generated interest in using this approach to treat solid tumors. Research results to date support the astounding clinical response rates of CD19-targeted CAR T cells, early clinical experiences in brain tumors demonstrating safety and evidence for disease-modifying activity, and the promise for further advances to ultimately assist patients clinically. However, several variable factors seem to slow down the progress rate regarding treating brain cancers utilizing CAR T cells. The current study offers a thorough analysis of CAR T cells' promise in treating brain cancer, including design and delivery considerations, current strides in clinical and preclinical research, issues encountered, and potential solutions.

How does TCR-T cell therapy exhibit a superior anti-tumor efficacy.

TCR-engineered T cells have achieved great progress in solid tumor therapy, some of which have been applicated in clinical trials. Deep knowledge about the current progress of TCR-T in tumor therapy would be beneficial to understand the direction. Here, we classify tumor antigens into tumor-associated antigens, tumor-specific antigens, tumor antigens expressed by oncogenic viruses, and tumor antigens caused by abnormal protein modification; Then we detail the TCR-T cell therapy effects targeting those tumor antigens in clinical or preclinical trials, and propose that neoantigen specific TCR-T cell therapy is expected to be a promising approach for solid tumors; Furthermore, we summarize the optimization strategies, such as tumor microenvironment, TCR pairing and affinity, to improve the therapeutic effect of TCR-T. Overall, this review provides inspiration for the antigen selection and therapy strategies of TCR-T in the future.

Preclinical development of a vaccine-based immunotherapy regimen (VBIR) that induces potent and durable T cell responses to tumor-associated self-antigens.

The development of therapeutic cancer vaccines remains an active area, although previous approaches have yielded disappointing results. We have built on lessons from previous cancer vaccine approaches and immune checkpoint inhibitor research to develop VBIR, a vaccine-based immunotherapy regimen. Assessment of various technologies led to selection of a heterologous vaccine using chimpanzee adenovirus (AdC68) for priming followed by boosts with electroporation of DNA plasmid to deliver T cell antigens to the immune system. We found that priming with AdC68 rapidly activates and expands antigen-specific T cells and does not encounter pre-existing immunity as occurs with the use of a human adenovirus vaccine. The AdC68 vector does, however, induce new anti-virus immune responses, limiting its use for boosting. To circumvent this, boosting with DNA encoding the same antigens can be done repetitively to augment and maintain vaccine responses. Using mouse and monkey models, we found that the activation of both CD4 and CD8 T cells was amplified by combination with anti-CTLA-4 and anti-PD-1 antibodies. These antibodies were administered subcutaneously to target their distribution to vaccination sites and to reduce systemic exposure which may improve their safety. VBIR can break tolerance and activate T cells recognizing tumor-associated self-antigens. This activation lasts more than a year after completing treatment in monkeys, and inhibits tumor growth to a greater degree than is observed using the individual components in mouse cancer models. These results have encouraged the testing of this combination regimen in cancer patients with the aim of increasing responses beyond current therapies.

Oncolytic attenuated measles virus encoding NY-ESO-1 induces HLA I and II presentation of this tumor antigen by melanoma and dendritic cells.

Antitumor virotherapy stimulates the antitumor immune response during tumor cell lysis induced by oncolytic viruses (OVs). OV can be modified to express additional transgenes that enhance their therapeutic potential. In this study, we armed the spontaneously oncolytic Schwarz strain of measles viruses (MVs) with the gene encoding the cancer/testis antigen NY-ESO-1 to obtain MVny. We compared MV and MVny oncolytic activity and ability to induce NY-ESO-1 expression in six human melanoma cell lines. After MVny infection, we measured the capacity of melanoma cells to present NY-ESO-1 peptides to CD4 + and CD8 + T cell clones specific for this antigen. We assessed the ability of MVny to induce NY-ESO-1 expression and presentation in monocyte-derived dendritic cells (DCs). Our results show that MVny and MV oncolytic activity are similar with a faster cell lysis induced by MVny. We also observed that melanoma cell lines and DC expressed the NY-ESO-1 protein after MVny infection. In addition, MVny-infected melanoma cells and DCs were able to stimulate NY-ESO-1-specific CD4 + and CD8 + T cells. Finally, MVny was able to induce DC maturation. Altogether, these results show that MVny could be an interesting candidate to stimulate NY-ESO-1-specific T cells in melanoma patients with NY-ESO-1-expressing tumor cells.

Advancing personalized medicine in brain cancer: exploring the role of mRNA vaccines.

Advancing personalized medicine in brain cancer relies on innovative strategies, with mRNA vaccines emerging as a promising avenue. While the initial use of mRNA vaccines was in oncology, their stunning success in COVID-19 resulted in widespread attention, both positive and negative. Regardless of politically biased opinions, which relate more to the antigenic source than form of delivery, we feel it is important to objectively review this modality as relates to brain cancer. This class of vaccines trigger robust immune responses through MHC-I and MHC-II pathways, in both prophylactic and therapeutic settings. The mRNA platform offers advantages of rapid development, high potency, cost-effectiveness, and safety. This review provides an overview of mRNA vaccine delivery technologies, tumor antigen identification, combination therapies, and recent therapeutic outcomes, with a particular focus on brain cancer. Combinatorial approaches are vital to maximizing mRNA cancer vaccine efficacy, with ongoing clinical trials exploring combinations with adjuvants and checkpoint inhibitors and even adoptive cell therapy. Efficient delivery, neoantigen identification, preclinical studies, and clinical trial results are highlighted, underscoring mRNA vaccines' potential in advancing personalized medicine for brain cancer. Synergistic combinatorial therapies play a crucial role, emphasizing the need for continued research and collaboration in this area.

Generation of induced pluripotent stem cell (iPSC) from NY-ESO-I-specific cytotoxic T cells isolated from the melanoma patient with minor HLAs: The practical pilot study for the adoptive immunotherapy for melanoma using iPSC technology.

Melanoma is one of the most severe skin cancers, derived from melanocytes. Among various therapies for melanoma, adoptive immunotherapy using tumor-infiltrating lymphocytes/chimeric antigen receptor-T cells (TCs) is advanced in recent years; however, the efficacy is still limited, and major challenges remain in terms of safety and cell supply. To solve the issues of adoptive immunotherapy, we utilized induced pluripotent stem cells (iPSCs), which have an unlimited proliferative ability and various differentiation capability. First, we monoclonally isolated CD8+ TCs specifically reactive with NY-ESO-1, one of tumor antigens, from the melanoma patient's monocytes after stimulated with NY-ESO-1 peptide by manual procedure, and cultured NY-ESO-1-specific TCs until proliferated and formed colonies. iPSCs were consequently generated from colony-forming TCs by exogenous expression of reprogramming factors using Sendai virus vector. After the RAG2 gene in TC-derived iPSCs (T-iPSCs) was knocked out for preventing T-cell receptor (TCR) rearrangement, T-iPSCs were re-differentiated into rejuvenated cytotoxic TCs. We confirmed that TCR of T-iPSC-derived TC was maintained as the same of original TCs. In conclusion, T-iPSCs have a potential to be an unlimited cell source for providing cytotoxic TCs. Our study could be a "touchstone" to develop iPSC-based adoptive immunotherapy for the treatment of melanoma for the future clinical use.

Signaling domains of cancer-associated glycolipids.

Immunotherapy of malignant cancers is now becoming one of representative approaches to overcome cancers. To construct strategies for immunotherapy, presence of tumor-specific antigens should be a major promise. A number of cancer specific- or cancer-associated antigens have been reported based on various experimental sets and various animal systems. The most reasonable strategy to define tumor-specific antigens might be "autologous typing" performed by Old's group, proposing three classes of tumor-antigens recognized by host immune systems of cancer patients. Namely, class 1, individual antigens that is present only in the patient's sample analyzed; class 2, shared antigens that can be found only in some group of cancers in some patients, but not in normal cells and tissues; class 3, universal antigens that are present in some cancers but also in normal cells and tissues with different densities. Sen Hakomori reported there were novel carbohydrates in cancers that could not be detected in normal cells mainly by biochemical approaches. Consequently, many of class 2 cancer-specific antigens have been revealed to be carbohydrate antigens, and been used for cancer diagnosis and treatment. Not only as cancer markers, but roles of those cancer-associated carbohydrates have also been recognized as functional molecules in cancer cells. In particular, roles of complex carbohydrates in the regulation of cell signaling on the cell surface microdomains, glycolipid-enriched microdomain (GEM)/rafts have been reported by Hakomori and many other researchers including us. The processes and present status of these studies on cancer-associated glycolipids were summarized.

Chemical and Synthetic Biology Approaches for Cancer Vaccine Development.

Cancer vaccines have been considered promising therapeutic strategies and are often constructed from whole cells, attenuated pathogens, carbohydrates, peptides, nucleic acids, etc. However, the use of whole organisms or pathogens can elicit unwanted immune responses arising from unforeseen reactions to the vaccine components. On the other hand, synthetic vaccines, which contain antigens that are conjugated, often with carrier proteins, can overcome these issues. Therefore, in this review we have highlighted the synthetic approaches and discussed several bioconjugation strategies for developing antigen-based cancer vaccines. In addition, the major synthetic biology approaches that were used to develop genetically modified cancer vaccines and their progress in clinical research are summarized here. Furthermore, to boost the immune responses of any vaccines, the addition of suitable adjuvants and a proper delivery system are essential. Hence, this review also mentions the synthesis of adjuvants and utilization of biomaterial scaffolds, which may facilitate the design of future cancer vaccines.

TANTIGEN 2.0: a knowledge base of tumor T cell antigens and epitopes.

We previously developed TANTIGEN, a comprehensive online database cataloging more than 1000 T cell epitopes and HLA ligands from 292 tumor antigens. In TANTIGEN 2.0, we significantly expanded coverage in both immune response targets (T cell epitopes and HLA ligands) and tumor antigens. It catalogs 4,296 antigen variants from 403 unique tumor antigens and more than 1500 T cell epitopes and HLA ligands. We also included neoantigens, a class of tumor antigens generated through mutations resulting in new amino acid sequences in tumor antigens. TANTIGEN 2.0 contains validated TCR sequences specific for cognate T cell epitopes and tumor antigen gene/mRNA/protein expression information in major human cancers extracted by Human Pathology Atlas. TANTIGEN 2.0 is a rich data resource for tumor antigens and their associated epitopes and neoepitopes. It hosts a set of tailored data analytics tools tightly integrated with the data to form meaningful analysis workflows. It is freely available at http://projects.met-hilab.org/tadb .

Merkel Cell Polyomavirus Small Tumor Antigen Activates Matrix Metallopeptidase-9 Gene Expression for Cell Migration and Invasion.

Merkel cell polyomavirus (MCV) small T antigen (sT) is the main oncoprotein for the development of Merkel cell carcinoma (MCC). MCC is a rare, clinically aggressive neuroendocrine tumor of the skin with a high propensity for local, regional, and distant spread. The dysregulation of matrix metalloproteinase-9 (MMP-9) has been implicated in multiple essential roles in the development of various malignant tumor cell invasion and metastasis. Previously, MCV sT was shown to induce the migratory and invasive phenotype of MCC cells through the transcriptional activation of the sheddase molecule, ADAM 10 (A disintegrin and metalloprotease domain-containing protein 10). In this study, we show that MCV sT protein stimulates differential expression of epithelial-mesenchymal transition (EMT)-associated genes, including MMP-9 and Snail. This effect is dependent on the presence of the large T stabilization domain (LSD), which is known to be responsible for cell transformation through targeting of promiscuous E3 ligases, including FBW7, a known MMP-9 and Snail regulator. Chemical treatments of MMP-9 markedly inhibited MCV sT-induced cell migration and invasion. These results suggest that MCV sT contributes to the activation of MMP-9 as a result of FBW7 targeting and increases the invasive potential of cells, which can be used for targeted therapeutic intervention.IMPORTANCE Merkel cell carcinoma (MCC) is the most aggressive cutaneous tumor without clearly defined treatment. Although MCC has a high propensity for metastasis, little is known about the underlying mechanisms that drive MCC invasion and metastatic progression. MMP-9 has been shown to play a detrimental role in many metastatic human cancers, including melanoma and other nonmelanoma skin cancers. Our study shows that MCV sT-mediated MMP-9 activation is driven through the LSD, a known E3 ligase-targeting domain, in MCC. MMP-9 may serve as the biochemical culprit to target and develop a novel approach for the treatment of metastatic MCC.

Identification of the Merkel Cell Polyomavirus Large Tumor Antigen Ubiquitin Conjugation Residue.

Merkel cell polyomavirus (MCPyV) large tumor (LT) antigen is a DNA binding protein essential for viral gene transcription and genome replication. MCPyV LT interacts with multiple E3 ligases in a phosphorylation-dependent manner, limiting its own viral replication by enhancing LT protein degradation, which is a unique mechanism for MCPyV latency. Thus, identifying LT ubiquitination sites is an important step toward understanding the biological role of these virus-host interactions that can potentially result in viral oncogenesis. The ubiquitin (Ub) attachment sites in LT were predicted by using Rapid UBIquitination (RUBI), a sequence-based ubiquitination web server. Using an immunoprecipitation approach, the lysine (Lys, K) 585 residue in LT is identified as the ubiquitin conjugation site. Lysine 585 is deleted from tumor-derived truncated LTs (tLTs), resulting in stable expression of tLTs present in cancers. Substitution of lysine 585 to arginine (Arg, R) increased LT protein stability, but impaired MCPyV origin replication, due to a loss of ATP hydrolysis activity. These findings uncover a never-before-identified ubiquitination site of LT and its importance not only in the regulation of protein turnover, but also in MCPyV genome replication.

MHC Class I Deficiency in Solid Tumors and Therapeutic Strategies to Overcome It.

It is now well accepted that the immune system can control cancer growth. However, tumors escape immune-mediated control through multiple mechanisms and the downregulation or loss of major histocompatibility class (MHC)-I molecules is a common immune escape mechanism in many cancers. MHC-I molecules present antigenic peptides to cytotoxic T cells, and MHC-I loss can render tumor cells invisible to the immune system. In this review, we examine the dysregulation of MHC-I expression in cancer, explore the nature of MHC-I-bound antigenic peptides recognized by immune cells, and discuss therapeutic strategies that can be used to overcome MHC-I deficiency in solid tumors, with a focus on the role of natural killer (NK) cells and CD4 T cells.

[Tumor vaccination-strategies and time points]. / Tumorvakzinierung ­Strategien und Timing.

BACKGROUND: Immunotherapies have gained increasing importance in the treatment of cancer in recent years. This also includes tumor vaccines, which are used therapeutically to direct the immune system specifically against tumor cells. OBJECTIVES: Different strategies of tumor vaccination, their current state of development, the optimal timing and possible combinations of cancer vaccines in the treatment of cancer are discussed. METHODS: Scientific publications on various tumor vaccination strategies based on ongoing studies that are listed on clinicaltrials.gov are summarized. CONCLUSIONS: For effective tumor vaccination, the selection of suitable tumor antigens present on the cell surface via human leukocyte antigen (HLA) molecules is essential. Suitable antigens should be present exclusively on tumor cells and able to induce a specific anti-tumor immune response, i.e. activate cytotoxic and T helper cells. For this purpose, neoepitopes derived from tumor-specific mutations or tumor-associated antigens (TAAs), which are present exclusively in tumor tissue due to altered gene expression or processing, can be used. For the application of the antigens, various strategies combined with suitable adjuvants are available, including peptide vaccines, DNA- or RNA-based vaccines, approaches with dendritic cells or whole tumor cell vaccines. Currently, numerous vaccination approaches as well as combination protocols are being evaluated in clinical trials with the aim to establish specific and low side effect immunotherapies to combat malignancies and enable long-term protection from disease recurrence via the induction of long-lasting antitumor immune responses.

Fast Screening of Whole Blood and Tumor Tissue for Bladder Cancer Biomarkers Using Stochastic Needle Sensors.

Bladder cancer is one of the most common urologic malignancies, which is more frequent in men than in women. The early diagnosis for this type of cancer still remains a challenge, therefore, the development of a fast screening test for whole blood and tumor tissue samples may save lives. Four biomarkers, p53, E-cadherin, bladder tumor antigen (BTA), and hyaluronic acid were considered for the screening tests using stochastic needle sensors. Three stochastic needle sensors, based on graphite powder and modified with three types of chitosan, were designed and characterized for the screening test. The proposed sensors showed low limits of quantification, and high sensitivity and selectivity levels. The recoveries of p53, E-cadherin, BTA, and hyaluronic acid in whole blood samples and tissue samples were higher than 95.00% with a relative standard deviation lower than 1.00%.

Sublethal Radiation Affects Antigen Processing and Presentation Genes to Enhance Immunogenicity of Cancer Cells.

While immunotherapy in cancer is designed to stimulate effector T cell response, tumor-associated antigens have to be presented on malignant cells at a sufficient level for recognition of cancer by T cells. Recent studies suggest that radiotherapy enhances the anti-cancer immune response and also improves the efficacy of immunotherapy. To understand the molecular basis of such observations, we examined the effect of ionizing X-rays on tumor antigens and their presentation in a set of nine human cell lines representing cancers of the esophagus, lung, and head and neck. A single dose of 7.5 or 15 Gy radiation enhanced the New York esophageal squamous cell carcinoma 1 (NY-ESO-1) tumor-antigen-mediated recognition of cancer cells by NY-ESO-1-specific CD8+ T cells. Irradiation led to significant enlargement of live cells after four days, and microscopy and flow cytometry revealed multinucleation and polyploidy in the cells because of dysregulated mitosis, which was also revealed in RNA-sequencing-based transcriptome profiles of cells. Transcriptome analyses also showed that while radiation had no universal effect on genes encoding tumor antigens, it upregulated the expression of numerous genes involved in antigen processing and presentation pathways in all cell lines. This effect may explain the immunostimulatory role of cancer radiotherapy.

Efficient Delivery and Replication of Oncolytic Virus for Successful Treatment of Head and Neck Cancer.

Head and neck cancer has been treated by a combination of surgery, radiation, and chemotherapy. In recent years, the development of immune checkpoint inhibitors (ICIs) has made immunotherapy a new treatment method. Oncolytic virus (OV) therapy selectively infects tumor cells with a low-pathogenic virus, lyses tumor cells by the cytopathic effects of the virus, and induces anti-tumor immunity to destroy tumors by the action of immune cells. In OV therapy for head and neck squamous cell carcinoma (HNSCC), viruses, such as herpes simplex virus type 1 (HSV-1), vaccinia virus, adenovirus, reovirus, measles virus, and vesicular stomatitis virus (VSV), are mainly used. As the combined use of mutant HSV-1 and ICI was successful for the treatment of melanoma, studies are underway to combine OV therapy with radiation, chemotherapy, and other types of immunotherapy. In such therapy, it is important for the virus to selectively replicate in tumor cells, and to express the viral gene and the introduced foreign gene in the tumor cells. In OV therapy for HNSCC, it may be useful to combine systemic and local treatments that improve the delivery and replication of the inoculated oncolytic virus in the tumor cells.