Agenda

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DAY ONE - April 4, 2013

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7:30 am Registration and Continental Breakfast

8:15 am Chairperson's Opening Remarks

Adrian Bot, MD, Ph.D., Chief Scientific Officer, Kite Pharma Inc.

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Session 1: Programming Stem Cells and T Cells for Adoptive T Cell Immunotherapy

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8:25 am Using Stem Cell-like T Cells in the Adoptive Immunotherapy of Cancer
Stem cells are defined by the ability to self-renew and to generate differentiated progeny. We will discuss how using stem cell-like T cells can overcome the limitations of current adoptive T cell therapies, including inefficient T cell engraftment, persistence and ability to mediate prolonged immune attack. Conferring stemness to antitumour T cells might unleash the full potential of cellular therapies.

Nicholas P. Restifo, MD, Principal Investigator, Center for Cancer Research, National Cancer Institute

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8:50 am Generation of Cancer Specific T cells from Human iPS Cells
In recent years iPS cell technology has shown to be a new and revolutionary tool in cell therapy and regenerative medicine field. In this session, Dr. Vizcardo will discuss the use of human iPS cells established from mature T lymphocytes with a cancer antigen specificity and their ability to generate huge quantities of cytotoxic T cells with the same antigen specificity.

Raul Vizcardo, Ph.D., Research Scientist, RIKEN Research Center for Allergy and Immunology

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9:15 am Programming Hematopoietic Stem Cells for T Cell Immunity Against Cancer
Dr. Yang has been interested in genetically modifying the various components of the immune system to target cancer and other chronic diseases, an approach named "Engineering Immunity." Hematopoietic stem cells (HSCs) are attractive targets due to their longevity, self-renewal and their potential to give rise to all types of immune cells. In this session, Dr. Yang will present her work covering the T cell receptor (TCR) gene-mediated programming of HSCs for T cell immunity against cancer, and the study of the in vivo dynamics of these engineered T cells using live animal imaging.

Lili Yang, Ph.D., Assistant Professor, Department of Microbiology, Immunology & Molecular Genetics, Eli & Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles

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9:40 am Immune System Regeneration with T Cell Receptor Engineering
Adoptive cell transfer of T cell receptor (TCR)-engineered T cells targeting cancer can be a viable treatment, but sustained T cell persistence and adequate functionality are still problematic. Dr. Koya will discuss their experience at UCLA and the prospects of utilizing Hematopoietic Stem Cells to overcome these issues.

Richard C. Koya, MD, Ph.D., Assistant Professor, Department of Surgery, Surgical Oncology, Member, JCCC Tumor Immunology Program, University of California, Los Angeles

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10:05 am Refreshment Break and Poster Viewing

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10:30 am Reprogramming Tumor-Immune Crosstalk to Overcome Breast Cancer Relapse
Dr. Manjili's presentation will do the following:

• Show how the immune cells are reprogrammed ex vivo
• Identify memory T cells, activated NKT cells and NK cells as key components of reprogrammed immune cells
• Show that reprogrammed immune cells are resistant to MDSC-mediated suppression
• Show anti-tumor efficacy of reprogrammed immune cells in prophylactic setting
• Show that relapsed breast tumor cells acquire characteristics of cancer stem-like cells
• Show that reprogrammed immune cells can overcome cancer stem-like tumor cells when combined with reprogramming of cancer stem-like tumor cells

Masoud H. Manjili, DVM, Ph.D., Associate Professor, Department of Microbiology & Immunology, Virginia Commonwealth University School of Medicine

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10:55 am Targeting Cancer Stem Cells Through Immunotherapy
The identification of brain cancer stem cells has led to a great opportunity to exploit the stem cell mechanisms to inhibit brain tumor initiation, progression, and invasion. Brain cancer stem cells – also called tumor initiating cells or tumor propagating cells - share features with normal neural stem cells but do not necessarily originate from stem cells. Although most cancers have only a small fraction of cancer stem cells, these tumor cells have been shown in laboratory studies to contribute to therapeutic resistance, formation of new blood vessels to supply the tumor and tumor invasion. Recent observations of the laboratory have demonstrated that these cancer stem cells are chemoresistant and may be the major reason for the recurrence of these deadly tumors. The lab has a major emphasis in the development of immunologic strategies to target cancer stem cells.

John Yu, MD, CEO, Immunocellular Therapeutics

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11:20 am Panel Discussion: Programming Stem Cells and T Cells for Adoptive T Cell Immunotherapy
Speakers from this session will be answering audience questions as well as pre-prepared questions on the subject of programming stem cells and t cells for adoptive T cell immunotherapy.

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12:00 pm Luncheon

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 Session 2: Biology and Immune Targeting of Cancer Stem Cells

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1:10 pm Treating Leukemia with T Cells Specific for Oncogenic Proteins Expressed in Leukemia Stem Cells
Modulating T cell immunity to treat human malignancies is showing increasing promise, but substantive obstacles remain to generating a T cell response that provides therapeutic benefit. Reproducibly effective therapy will require many factors be in place, including an appropriate antigenic target, establishment of a high avidity and high magnitude T cell response, and the ability of the tumor-reactive T cells to infiltrate and retain function in the tumor microenvironment. We have been systematically investigating strategies to address these issues. To identify targetable leukemia antigens, we collaborated with the Weissman/Majeti labs at Stanford University to compare gene expression profiles in purified leukemic stem cells with profiles in normal hematopoietic stem cells and other somatic cells, and identified two promising targets associated with the leukemic phenotype, WT1 and Cyclin A1, to which CD8 T cells that lyse leukemic cells can be generated. Generating sufficient numbers of specific T cells with high avidity for the target in each patient is a substantive problem. We will discuss a just completed trial targeting WT1 in leukemia patients, which highlights the potential benefit of providing potent T cell responses to this pro-oncogenic protein. For this trial, panels of WT1-specific CD8 T cells clones were generated for each patient and the highest avidity clone was identified, isolated, and then expanded for adoptive therapy. However, this approach is limited by the quality of the responses elicited in each patient. As many patients have immune repertoires compromised from prior therapy, this could be overcome by cloning the T cell receptor (TCR) gene from a defined high avidity leukemia-reactive T cell that can then be introduced into large numbers of patient T cells to create a standardized reagent for treatment of patients whose tumor expresses the target antigen and shares the MHC restricting allele. However, even in this setting the avidity of transduced T cells used for therapy will be limited by the affinity of the introduced TCR, and high affinity TCRs for tumor antigens that are also normal self-antigens may not be readily identified in normal repertoires. As the CDR3 regions of the Vα and Vβ TCR chains represent the regions that predominantly make contact with the epitope in the peptide/MHC complex, with CDR1 and CDR2 primarily responsible for orienting the TCR on the MHC complex, our lab developed, in collaboration with David Kranz’ lab at the University of Illinois, methods to selectively mutate/alter the CDR3 regions of the isolated antigen-specific TCR chains prior to introduction into recipient T cells to improve the affinity for the target antigen. Additionally, we recently developed methods to interrogate the full repertoire of β -chain rearrangements capable of pairing with a defined TCR α-chain before negative selection, and to isolate the β-chains that enhance the affinity of the TCR for the peptide epitope. Evaluation of the in vivo activity and safety of such TCRs in relevant mouse models has revealed that, for many pro-oncogenic proteins over-expressed in tumors but detected at low levels in normal cells, the thymic selection process is eliminating TCRs with high affinity for the antigen that would be safe in the periphery, not causing autoimmune injury, and would be more effective in targeting tumors.

Philip D. Greenberg, MD, Professor of Medicine and Immunology, University of Washington and Head, Program in Immunology, Fred Hutchinson Cancer Research Center

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1:35 pm EGFRvIII and Cancer Stem Cells: Why a Rarely Expressed Tumor Antigen Is a Good Cancer Vaccine Target

Dr. Wong's presentation will cover the following:

• EGFRvIII is an in-frame alteration of the EGF receptor in glioblastoma due to a gene rearrangement
• While the genetic alteration is ubiquitous, EGFRvIII protein expression is relatively rare (<10% of cells)
• EGFRvIII is highly associated with the cancer stem cell population in glioblastoma
• Phase II trials show a 50% increase in survival for patients vaccinated with a peptide vaccine based on EGFRvIII

Albert J. Wong, MD, Professor, Director, Brain Tumor Research Laboratories, Department of Neurosurgery/Cancer Biology Program, Stanford University Medical Center

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2:00 pm CSPG4-targeted Monoclonal Antibody-based Immunotherapy for Solid Tumors
The characteristics of the tumor antigen chondroitin sulfate proteoglycan 4 (CSPG4) will be reviewed with special emphasis on why CSPG4 is an attractive target for mAb-based immunotherapy of malignant diseases. Examples of the anti-tumor activity of CSPG4-specific monoclonal antibodies will be described. Lastly, strategies to eradicate cancer initiating cells with CSPG4-specific monoclonal antibodies will be discussed.

Soldano Ferrone, MD, Ph.D., Division of Surgical Oncology, Department of Surgery, Massachusetts General Hospital, Harvard Medical School

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2:25 pm Targeting Cancer Stem Cells Using Genetically Engineered T Cells
Adoptive cell transfer using anti-tumor antigen reactive T cells has proven to be a useful strategy for the treatment of metastatic melanoma, with objective response rates of up to 72%, and nearly 20% of patients rendered disease free. These studies involved the extraction and ex-vivo expansion of naturally occurring tumor-infiltrating lymphocytes (TIL). As an alternative approach to TIL therapy, high-affinity T cell receptors (TCR) can be introduced into normal T cells using retroviral vectors, and the adoptive transfer of these cells into the lymphodepleted patients has been shown to mediate cancer regression. Unlike a conventional TCR, a chimeric antigen receptor (CAR) is capable of relaying excitatory signals to T cells in a non-MHC-restricted manner. Several clinical trials using CAR-transduced T cells have been reported, and efforts targeting CD19 have led to the effective elimination of lymphoma in patients.  As an approach to develop immune based therapies for glioblastoma we sought to target antigens expressed in glioma stem cells (GSC).  GSC have multiple properties that make them significantly more representative of glioma tumors than established glioma cell lines and we identified that GSC lines express two potential targets, chondroitin sulfate proteoglycan 4 (CSPG4) and epidermal growth factor receptor variant III (EGFRvIII).  

EGFRvIII is the result of a novel tumor specific gene rearrangement that produces a unique protein expressed in approximately 30% of gliomas, and is an ideal target for immunotherapy because of its lack of expression on normal tissues. Based on the sequence information of seven EGFRvIII specific monoclonal antibodies (mAb), we assembled chimeric antigen receptors (CAR) and evaluated the ability of CAR-engineered T cells to recognize EGFRvIII.  Three of these anti-EGFRvIII CAR-engineered T cells produced the effector cytokine, IFN-g? and lysed antigen expressing target cells.   We concentrated development on a CAR produced from human mAb 139, which specifically recognized GSC lines and glioma cell lines expressing mutant EGFRvIII but not wild type EGFR and did not recognize any normal human cell tested.  Using the 139-based CAR, T cells from glioblastoma patients could be genetically engineered to recognize EGFRvIII expressing tumors and could be expanded ex vivo to large numbers, and maintained their anti-tumor activity.  Based on these observations, a gamma-retroviral vector expressing this EGFRvIII CAR was produced and a clinical trial initiated in EGFRvIII+ glioma patients.

Richard A. Morgan, Ph.D., Staff Scientist, Surgery Branch, Tumor Immunology Section, National Cancer Institute

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2:50 pm Refreshment Break and Poster Viewing

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3:15 pm The Translational Biology of Cancer Stem Cells
Dr. Matsui's presentation will cover the following:

• Basic biology and discovery of cancer stem cells
• Identification of cancer stem cell targeting strategies
• Development of clinical approaches to target cancer stem cells

William Matsui, MD, Associate Professor of Oncology, Division of Hematologic Malignancies, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine

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3:40 pm Immunological Targeting of Brachyury, a Transcription Factor involved in EMT
The epithelial-mesenchymal transition (EMT) is being recognized as a process of relevance to the progression of solid tumors. Tumor EMT has been associated with metastasis as well as with the acquisition of resistance mechanisms that would reduce the anti-tumor effects of radiation, chemotherapy, and certain small-molecule targeted therapies. An association has also been demonstrated between tumor EMT and the acquisition of features of cancer stem cells. Dr. Palena's group has identified and characterized the T-box transcription factor Brachyury, as a novel driver of EMT in human carcinomas. Brachyury is a molecule highly expressed in various human tumors of epithelial origin, but rarely expressed in human normal adult tissues, and it is also an immunogenic molecule. Based on their results, they propose to target tumor cells undergoing EMT via the use of Brachyury-based cancer vaccines. A Phase I clinical trial of a yeast recombinant vector encoding for the Brachyury protein is currently ongoing in patients with advanced carcinomas. Her presentation will include an overview of the role of Brachyury in EMT and resistance to conventional therapies; the development of cancer vaccines targeting Brachyury and potential future combinations of these vaccines with other agents to improve anti-tumor efficacy.

Claudia M. Palena, Ph.D., Head, Immunoregulation Group, Laboratory of Tumor Immunology and Biology, Investigator, National Cancer Institute

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4:05 pm Targeting HER-2 Expressing Cancer Stems Cells in Luminal Breast Cancers Using Dendritic Cell Vaccines
Dr. Czerniecki's presentation will cover the following:

• Luminal Breast Cancer ER+ often contains breast cancer stem cells expressing HER-2 but not gene amplified. Patients with ER+HER-2+ 2 FISH negative phenotype have high risk of late recurrence. Combination of ER+ and HER-2 expression in DCIS is associated with high risk of development of invasive breast cancer.
• HER-2 pulsed DC1 vaccines are effective in inducing CD4, CD8 T cell responses in HER-2 high expressing DCIS and early invasive breast cancer as well as intermediate expressing HER-2 early luminal cancers.
• DC1 vaccines effectively eliminate HER-2 expressing DCIS cells in the HER-2 2+ population compared with HER-2 high expressing early breast cancers. In some cases changing the phenotype of residual disease to that of Luminal A.
• DC1 Vaccines against HER-2 may be useful adjuvants to eliminate HER-2 expressing breast cancer stem cells that may be responsible for many late recurrences in patients with ER+ luminal breast cancers and a trial to assess the DC1 vaccines in such patients after adjuvant therapy is being explored.

Brian J. Czerniecki, MD, Ph.D., Rhodes-Harrington Professor in Surgical Oncology, University of Pennsylvania and Co-Director, Rena Rowan Breast Center

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4:30 pm Panel Discussion: Biology and Immune Targeting of Cancer Stem Cells
Speakers from this session will be answering audience questions as well as pre-prepared questions on the subject of biology and immune targeting of cancer stem cells.

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 DAY TWO - April 5, 2013

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7:30 am Continental Breakfast

8:00 am Chairperson's Opening Remarks

Adrian Bot, MD, Ph.D., Chief Scientific Officer, Kite Pharma Inc.

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Session 2 (continued): Biology and Immune Targeting of Cancer Stem Cells

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8:10 am Innovative Engineering Approaches to Focused T cell-based Therapy of Cancer
Dr. Powell's presentation will cover the following:

• Lentiviral gene transfer conferred redirection of human T cells to specific tumor antigens.
• Engineering T cells for universal cancer antigen recognition and response to cancer stem cells.
• Novel focusing strategies to enhance tumor immunity but limit long-term toxic effects to normal tissues.

Daniel J Powell Jr., Ph.D., Research Assistant Professor, Department of Pathology and Laboratory Medicine and Department of Obstetrics and Gynecology, University of Pennsylvania

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8:35 am CaspaCIDe™ Enables the Control of Cell Therapy Toxicity
In this presentation, Dr. Spencer will discuss efficacy and potential cell therapy applications of inducible Caspase-9 (CaspaCIDe™) technology. CaspaCIDe is a rapid, cell cycle-independent and non-immunogenic suicide gene that is triggered by the membrane-permeable, synthetic dimerizer ligand, AP1903. Clinical proof of principle has been demonstrated in a Phase I/II trial in the HSCT setting. Potential use of CaspaCIDe to enable emerging stem cell therapies and tumor-targeting T cells will also be discussed.

David M. Spencer, Ph.D., Chief Scientific Officer, Bellicum Pharmaceuticals, Inc.

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9:00 am Sustained Tumor Regression Induced by an Antibody-drug Conjugate That Targets 5T4, an Oncofetal Antigen Expressed on Tumor-initiating Cells
Treatment of human tumors with antibody drug conjugates (ADCs) is a promising therapeutic strategy for the clinical management of cancer. We have identified the 5T4 oncofetal protein as an ADC target expressed on tumor-initiating cells in NSCLC. Anti-5T4 ADCs are potent therapeutic compounds capable of inducing long-term and stable tumor regressions despite heterogeneous expression of the target in several xenograft models. We have optimized and selected a lead anti-5T4 ADC (A1mcMMAF) with encouraging preclinical efficacy and safety data that support clinical development.

Kenneth Geles, Ph.D., Senior Principal Scientist, Oncology Research Unit, Pfizer Inc.

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9:25 am Development of Therapeutic Antibodies Targeting Cancer Stem Cells
Dr. Hurt's presentation will cover the following:

• The development of a novel high-throughput assay to identify anti-CSC targets (recently published some of this in Stem Cells Translational Medicine)
• Clinical trial designs for anti-CSC therapy and the development of biomarkers assessing anti-CSC activity
• Identification of novel CSC targets

Elaine Hurt, Ph.D., Scientist II, MedImmune

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9:50 am Refreshment Break and Poster Viewing

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10:10 am Autologous Cancer Stem Cells in Immunotherapy: Getting to the Heart of Cancer
Dr. Cornforth's presentation will cover the following:

• Cancer stem cells in solid tumors
• Dendritic cells and cancer stem cells immune interactions
• Results of clinical trials involving cancer stem cell derived cell therapies

Andrew Cornforth, Ph.D., Cancer Stem Cell Program Manager, California Stem Cell, Inc.

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10:35 am Challenges and Solutions for the Commercial Manufacture of Immunomodulatory Cell Products
Over the last decade, advances in understanding the cellular mechanisms involved with immune response and modulation has enabled the development of therapies to treat a multitude of intractable diseases associated with disregulation of the immune system.  There are ongoing clinical trials using manufactured dendritic cells, NK cells, and T cells to treat cancer, viral infections and inflammatory and autoimmune diseases.  Clinical manufacture of these types of cell products may require multiple steps such as isolation of specific cell populations and genetic modification, leading to processes that are technically complex, lengthy, and potentially expensive.   As these products and therapies enter larger clinical trials and commercialization, manufacturing processes must be improved to increase efficiencies and reduce cost of goods to make these therapies be economically viable.  This effort must also include development of reproducible and cost effective assays for interim and final product characterization for controlling an efficient and consistent commercial process.  PCT has over 14 years of cell therapy manufacturing and will present our experience on the development of processes and assays for the clinical and commercial production of cell based therapies.

Robert Preti, Ph.D., President and Chief Scientific Officer, PCT Cell Therapy Services

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11:00 am Cancer Testis Antigens on Tumor Initiating Cells:  A Rich Source of Immunotherapy Targets
Cancer testis antigens (CTAs) are a class of tumor-associated antigens typically expressed in embryonic stem cells and testicular germ cells, and showing little or no expression in most somatic tissues. While they are aberrantly expressed in a number of malignancies, they do not harbor mutations associated with their pathological function as do, for instance, most of other cancer genes. Instead, CTAs are commonly up-regulated because of DNA hypomethylation, which is frequently seen in tumor cells, as demonstrated by several studies showing a correlation between CTA expression and promoter methylation status. Therefore, the cause of CTA-associated pathological function in cancer cells is the aberrant expression of normal CTA genes, and not the generation of mutated versions of these genes. Such epigenetic regulation of CTA is typical of pluripotent cells, especially germ cells, and of placental cells. Therefore, the hypothesis exists that CTA expression is a hallmark of tumor-initiating cells (TIC) in human cancers. As TIC are the only self-renewing tumor cells, they are required for constant tumor growth. Furthermore, they are intrinsically resistant to available therapies. Therefore, they were postulated to underlie cancer chemo-resistance and relapse. Lastly, the stemness abilities shown by TIC are also likely to confer metastatic potential to cancer cells, considering that epithelial mesenchymal transition can convey stemness and motility at the same time. As a result, from the point of view of anti-cancer therapy, TIC represents a target of exceptional interest. Based on these observations, CTAs are a growing source of targetable proteins to eliminate TIC. We have evidenced and validated the aberrant expression and immunogenicity of the CTAs, SP17, AKAP4, Ropporin, and PTTG1, in tumors of different histological origins, namely ovarian cancer, multiple myeloma, prostate and lung cancer.  In the majority of tumors studied we were able to detect CTA expression at the cell surface, making these molecules promising targets for immunotherapeutic approaches.   Furthermore, CTA surface expressions also make them excellent targets for the development of diagnostic assays, especially in biological fluids.  Thus, aberrant expression of CTA by TIC offers the opportunity to develop therapeutic and diagnostic strategies directed against this neoplastic cell subset, responsible for treatment resistance, disease progression and mortality of patients with cancer.

Maurizio Chiriva-Internati, DBSc, Ph.D., Director of Basic/Translational Research Program, Division of Hematology & Oncology, Southwest Cancer Research & Treatment Center at University Medical Center, Texas Tech University of Health Sciences Center School of Medicine

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11:25 am Panel Discussion: Biology and Immune Targeting of Cancer Stem Cells
Speakers from this session will be answering audience questions as well as pre-prepared questions on the subject of biology and immune targeting of cancer stem cells.

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12:05 pm End of Conference