1. TUMOR IMMUNOLOGY

2. MORE THAN 100 VARIOUS TUMOR TYPES MULTISTEP TUMORIGENESIS DYNAMIC CHANGE OF TUMOR GENOME –Genetic instability –Oncogenes – ‘gain of function’ change –Tumor suppressor genes – recessive ‘loss of function’ change PROGRESSIVE TRANSFORMATION –Benign tumor abnormal, but limited growth –Malignant tumor unlimited growth, break basal membranes, invasion –Metastatic tumor seeds new tumors at distant sites. MULTIPLE LIMITING AND INHIBITORY CHECK POINTS –Growth advantage –Selection REGULATORY CIRCUITS –Inherent cell autonomous regulatory mechanisms –Microenvironmental factors Cancer is a result of multiple mutations INDEPENDENT OF THE IMMUNE SYSTEM

3. Benign or malignant tumors

4. ACTIVATION OF ONCOGENES Mitogens Growth factor receptors Secondary messengers Tarnscriptional activators Cell cycle genes INACTIVATION OF TUMOR SUPPRESSOR GENES Growth inhibitors Cell cycle inhibitors Programmed cell death genes DNA repair enzymes Unlimited proliferation Sustained angiogenesis Tissue migration and metastasis ACQUIRED PROPERTIES Independent growth factor signals Resistance to growth inhibitory factors Avoid apoptosis Hanahan D és Weinberg RA 2000 Cell Tumor stem cell Tissue cell Malignant cell Malignant transformation

5. Normal epithelial cells 2 APC mutation Inherited Adenomatous polip 1 Ras mutation Adenomatous polip 2 p53 mutation Colon carcinoma Chromosomal translocation Metastatic colon carcinoma The „multi-hit” model of tumorigenesis Knudson A.G. 2001 Reaction of the immune system TOLERANCE RECOGNITION Tumor antigens Individual TSA Common TAA CEA TOLERANCEIMMUNE RESPONSE DANGER INNATE/AQUIRED IMMUNITY

6. Oncogenesis MechanismActionExample Growth promotion Overexpression of growth factor receptors (such as epidermal growth factor, or EGF) making cells more sensitive to growth stimuli c-erb-B2 Increased growth factor signal transduction by an oncogene that lacks the GTPase activity that limits GTP induction of cytoplasmic kinases that drive cell growth ras Overexpression of a gene product by stimulation from an oncogene (such as ras)c-sis Lack of normal gene regulation through translocation of a gene where it is controlled by surrounding genes to a place where it is no longer inhibited c-abl Binding of oncogene product to the nucleus with DNA transcriptional activation to promote entry into the cell cycle c-myc Loss of tumor suppressor gene function Lack of regulation of cell adhesion with loss of growth control through cell interactionAPC Loss of down-regulation of growth promoting signal transductionNF-1 Loss of regulation of cell cycle activation through sequestation of transcriptional factorsRb Loss of regulation of cell cycle activation through lack of inhibition of cell proliferation that allows DNA repair p53 Limitation of Apoptosis Overexpression of gene, activated by translocation, prevents apoptosisbcl-2

7. OncogeneAssociated Neoplasms c-erb-B2 Breast and ovarian carcinomas ras Many carcinomas and leukemias c-sis Gliomas c-abl Chronic myelogenous leukemia, acute lymphocytic leukemia c-myc Lymphomas BRCA-1 Breast and ovarian carcinomas APC Colonic adenocarcinomas NF-1 Neurofibromas and neurofibrosarcomas Rb Retinoblastomas, osteosarcomas, small cell lung carcinomas p53 Many carcinomas bcl-2 Chronic lymphocytic leukemia, lymphomas VARIOUS ONCOGENES ARE ASSOCIATED WITH DEFINED NEOPLASMS

8. CHROMOSOMAL TRANSLOCATION IN BURKITT’S LYMPHOMA Uncontrolled proliferation due to the activation of c-myc oncogene EBV induced tumor 8148q-14q+ c-myc CH VH c-myc CH VH

9. THE IMMUNE RESPONSE TO TUMORS Hidden, changing, proliferating, evolving target Immune surveillence –Few non-self antigens –Poorly immunogenic –Recognized by B and T lymphocytes Tolerance induction –Tumor antigens do exist –Recognized primarily by T lymphocytes –Induce tolerance TUMOR ANTIGENS Tumor associated antigens – TA Present also in normal cells Aberrant/disregulated expression in tumor cells Tumor specific antigens – TSA Unique for individual tumors or tumor types IMMUNE SYSTEM Tumor-specific immune responses can be induced Cytotoxic T lymphocytes can eradicate tumors

10. MHC-dependent rejection of tumors

11. Infective facial tumor in the inbread populations of the Tasmanian devil About 2/3 of Hungary Population half million

12. Tumor antigens and tumor associated antigens

13. Tumor-specific antigens

14. Cancer/testis antigens are expressed almost entirely by cancerous cells, showing little or no expression in healthy tissue, with the exception of normal testis, embryonic ovaries and placenta. No MHC expression Many of them X-linked Over 100 in total --- Potential targets for immune therapy

15. STRUCTURE AND SOURCE OF TUMOR ANTIGENS MUTATED ONCOGENS AND TUMOR SUPPRESSOR GENES –Involved in transformation –Cytosolic novel determinants - no major targets –Cellular proto-oncogenes  oncogene Ras, p53, Abl Point mutation, deletion, chromosomal translocation, viral gene insertion ABERRANTLY OVEREXPRESSED NORMAL CELLULAR PROTEINS –Low/rare expression in normal cell – ignorance by the immune system TUMOR ANTIGENS ENCODED BY GENOMES OF ONCOGENIC VIRUSES –Immunogenic shared viral proteins DNA viruses – Simian virus 40, a polyomavirus that is found in both monkeys and humans. (Large T-antigen, binds and inactivates p53) Herpes, EBV- LMP protein strongly trasforming. Homologue of CD40 Papilloma HPV16 HPV18 RNA viruses – Retroviruses HTLV ONCOFETAL ANTIGENS –Silenced during development  de-repressed in tumor cells –Tumor markers – carcinoembryonic antigen CEA, specific for carcinomas –Alpha-fetoprotein AFP, hepatocellular carcinoma TISSUE-SPECIFIC DIFFERENTIATION ANTIGENS –CD10/CALLA Common Acute Lymphoid Leukemia Antigen, Melanoma

16. macrophage DS NK/γδ CD4/CD8 PROTECTION ELIMINATION Immunsurveillence EQUILIBRIUMESCAPE Genetic instability Immune selection Treg cells TUMOR CD8 macrophage DS NK/γδ CD4/CD8 METASTASIS ESCAPING TUMOR VARIANTS

17. Activation of tumor-specific T-cells by DC Cross-presentation

18. INDUCTION OF A PROTECTIVE ANTI-TUMOR IMMUNE RESPONSE REQUIRES THE COLLABORATION OF DENDRITIC CELLS AND T- LYMPHOCYTES IL-2 IFN  Tumor Ag CROSS PRIMING APOPTOTIC TUMOR CELL DC IL - 12

19. Cytotoxic T-lymphocytes recognize tumor cells Activated cytotoxic T-lymphocytes kill tumor cells CONSEQUENCES OF T-CELL MEDIATED IMMUNITY

20. Manipulation of the immune response by a tumor.

21. TOLERANCE INDUCTION BY DENDRITIC CELLS SIGNAL 1Tumor antigenYES SIGNAL 2 Tumor cellNO Activated APCYES SIGNAL 3Natural immunityNO InflammationNO Tumor-associated macrophage (upto 40% of non-malignant cells) M1 macrophage: MHCII, CD80, 86 High iNOS, M2 macrphage: arginase +

22. TUMOR ANTIGENS –Soluble tumor antigens – inhibit recognition on the cell surface –Antigen modulation – antibody dependent internalization –Masking – antibody binds, no effector function –Low immunogenicity –Peptide antigens – mutations affecting Tc or Th epitopes ANTIGEN PRESENTATION –Direct presentation – non professional APC, no MHC class II, no co-stimulatory molecules –Indirect presentation – by professional APC, soluble CD40 and CD40 ligand inhibit CYTOTOXIC T CELL ACTIVITY –MHC – mutation, altered intracellular transport, β2m, locus, allele –Peptide loading – mutation, tumor derived peptides are not presented, TAP APOPTOSIS –Soluble Fas – inhibits Fas ligand-mediated apoptosis TUMOR DERIVED INHIBITORY FACTORS –TGFβ – G1 block, inhibits tumor growth if sensitive  tumors loose their TGFβ receptor –TGFβ inhibits immune cell activation –PGE2 – immune suppression TUMOR DERIVED POTENTIATING FACTORS –Angiogenesis factors – secreted by tumor tissue cells or by immune cells ESCAPE MECHANISMS OF TUMOR CELLS AND TUMOR TISSUES

23. Human epithelial tumours can inhibit the response of lymphocytes expressing NKG2D

24. Vaccination of melanoma patients may cause their tumor to regress

25. AZ AKTÍV TUMOR-SPECIFIKUS IMMUNTERÁPIA LEHETŐSÉGEI A tumor antigének beviteli módja Tumor protein Tumor protein- derived peptide Anti-idiotipe Ab Vírus-tumor genome Plasmid DNA Modified tumor cell Irradiated tumor cell Heat shock protein Modified DC Mocellin S et al. Lancet Oncology 2004 Tumor cell lysate Loaded DC ANTI-TUMOR IMMUNOTHERAPY

26. Humanized monoclonal antibodies used in the treatment of patients with cancer.

27. DIAGNOSIS OF TUMORS BY PET