1.Immunotherapy in Cancers Prof. M.C.Bansal MBBS,MS,MICOG,FICOGProfessor OBGY Ex-Principal & ControllerJhalawar Medical College & HospitalMahatma Gandhi Medical College, Jaipur.

2. Tumor cell proliferation andimmunotheray of cancers Professor M. C. Bansal M.B.B.S. M.S. F.I.C.O.G M.I.C.O.G 3. Cell Cycle Information on growth patterns and doubling timesrelates to the growth of the tumor mass as a whole.The kinetic behavior of individual tumor cells hasbeen well described, and a classic cell cycle model hasbeen produced . M phase (mitotic phase) of the cell cycle is the phaseof cell division. G1 phase (postmitotic phase) is a period of variableduration when cellular activities and protein and RNAsynthesis continue. These G1 cells can differentiate orcontinue in the proliferative cycle. 4. S phase (DNA synthetic phase) is the period in whichnew DNA replication occurs. G2 phase (postsynthetic phase) is the period in whichthe cell has a diploid number of chromosomes andtwice the DNA content of the normal cell. The cellremains in this phase for a relatively short time andthen enters the mitotic phase again. G0 phase (the resting phase) is the time during whichcells do not divide. Cells may move in and out of theG0 phase. 5. The generation time is the duration of the cycle from M phase to M phase. Variation occurs in all phases of the cell cycle, but the variation is greatest during the G1 period. The reasons for this variation are complex and not completely understood. 6. These cell cycle events have important implications forthe cancer therapist. Differential sensitivities to chemotherapy andradiation therapy are associated with differentproliferative states. Dividing cancer cells that are actively traversing thecell cycle are very sensitive to chemotherapeuticagents. 7. Cells in a resting state (G0) are relatively insensitive tochemotherapeutic agents, although they occupy spaceand contribute to the bulk of the tumor. 8. Cell Kinetics In cell kinetic studies performed on humantumors, the duration of the S phase (DNA synthesisphase) is relatively similar for most humantumors, ranging from a low of 10 hours to a high ofapproximately 31 hours. The length of the cell cycle in human tumors variesfrom slightly more than half a day to perhaps 5 days. With cell cycle times in the range of 24 hours anddoubling times in the range of 10 to 1,000 days, it isclear that only a small proportion of tumor cells are inactive cell division at any one time. 9. Two major factors that affect the rate at which tumorsgrow are the growth fraction and cell death. The growth fraction is the number of cells in thetumor mass that are actively undergoing cell division. There is a marked variation in the growth fraction oftumors in human beings, ranging from 25% to almost95%. 10. In the past, it was thought that human tumorscontained billions of cells, all growing slowly. In actuality, only a small fraction of cells in a tumormass are rapidly proliferating; the remainder are out ofthe cell cycle and quiescent. Cancer stem cells are a very small population of cellsthat appear to be relatively chemoresistant; these playa major role in the development and progression ofcancers. 11. Tumor growth may be altered by the following: cytotoxic chemotherapy, which alters both the generationtime and the growth fraction of a tumor hormones, which appear to alter the growth fractionwithout changing the generation time radiation therapy, which alters both the generation timeand the growth fraction alterations in oxygen tension and vascular supply, whichalter the growth fraction without altering generation time immunologic therapies, which seem to alter bothgeneration time and growth fraction 12. INTRODUCTION Cancer is caused by a series of events that include theaccumulation of successive molecular lesions andalterations in the tumor microenvironment . Molecular lesions include overexpression, amplification, ormutations of oncogenes; deletion of tumor suppressorgenes; and the inappropriate expression of growth factorsand their cellular receptors. In addition to these molecular changes, the formation ofnew blood vessels (angiogenesis) and the lack of effectivehost antitumor immune responses create amicroenvironment that supports the growth of cancer . 13. Our improved understanding of these mechanismspresents an opportunity for the development of noveltherapeutic approaches . This presentation provides an overview ofbiologic, targeted, and immunotherapeutic strategiesfor gynecologic cancers. 14. Biologic and Targeted Therapies The growth of cancer cells is crucially dependent ononcogenic signal transduction pathways. Extracellular signals are transmitted to the cancer cell viatransmembrane receptors. Activation of the epidermal growth factor receptors(EGFR, HER2, HER3, and HER4), for example, stimulates acascade of intracellular proteins that ultimately lead tochanges in gene expression. Novel therapeutics are targeted to modulate these signaltransduction pathways by blocking the extracellulartransmembrane receptors or interfering with intracellularproteins such as tyrosine kinases further downstream. 15. This novel therapeutic approach is also termedmolecular targeting . It is accomplished by either monoclonal antibodiesthat bind to transmembrane receptors and serumproteins such as vascular endothelial growth factor(VEGF) or chemical, small-molecule inhibitors thatprevent activation of signal transduction proteins. Targeting the signaling cascade inhibits theproliferation of cancer cells, induces apoptosis, andblocks metastasis. 16. The specificity of these molecules is based on theassumption that cancer cells are overexpressingvarious proteins in the signal transductionpathways, therefore presenting a preferred targetcompared to normal cells. Conceptually, this should result in more cancer cell-specific therapy and less clinical side effects because ofsparing of normal tissue 17. Angiogenesis The formation of new blood vessels (neoangiogenesis) is anormal process during embryonic development, tissueremodeling, and wound healing . Malignant tumors are able to induce angiogenesis bysecreting paracrine factors that promote the formation ofnew blood vessels. Angiogenesis is a complex process that is influenced byvarious pro-and antiangiogenic factors, includingVEGF, interleukin 8, platelet-derived endothelial cellgrowth factor, and angiopoietins. Overexpression of these angiogenic factors leads toneovascularization and increased supply of nutrients andoxygen to the tumor. 18. Three main therapeutic strategies that targetangiogenesis are currently being explored for thetreatment of cancer patients . One group of agents targets VEGF(e.g., bevacizumab, VEGF-Trap), the second groupprevents VEGF from binding to its receptor(pertuzumab), and a third group of agents inhibitstyrosine kinase activation and downstream signalingin the angiogenesis signaling cascade(valatanib, sunitenib). 19. Vascular Endothelial Growth Factor VEGF is overexpressed in gynecologicmalignancies, therefore presenting an excellent targetfor therapy . Inhibition of VEGF-induced angiogenic signalingdecreases tumor microvascular density and causesdeath of solid tumors in various preclinical models. Several agents are now available for clinical use; alltarget the VEGF signaling pathway. The most widely used agent at this time isbevacizumab, a humanized, recombinant monoclonalantibody that binds to all isoforms of VEGF-A. 20. In ovarian carcinoma, various clinical trials havedemonstrated the efficacy of bevacizumab treatment. In a study by the Gynecologic Oncology Group, 62patients received single agent bevacizumab 15 mg/kgintravenously every 21 days . Thirteen patients (21%) showed clinical responseswith two complete and 11 partial responses. The median response duration was 10 months, and 25patients (41.3%) survived progression free for at least 6months. 21. Bevacizumab has also been used in combination with otheragents. In a phase II study of 13 patients with recurrent ovarian orprimary peritoneal carcinoma, combination treatment withbevacizumab (15 mg/kg i.v. every 21 days) and erlotinib (150mg/day orally) resulted in one complete response and onepartial response for a total response rate of 15% . Seven patients had stable disease. Another trial investigated the combination of bevacizumab(10 mg/kg every 14 days) and oral cyclophosphamide (50mg/day orally) in 70 patients with recurrent ovarian cancer. 22. The Gynecologic Oncology Group has initiated aclinical trial that will evaluate the addition ofbevacizumab to first-line chemotherapy after primarytumor debulking. A similar trial by the Gynecologic Cancer InterGroup isdesigned to evaluate the safety and efficacy of addingbevacizumab to standard chemotherapy (carboplatinand paclitaxel) in patients with advanced epithelialovarian or primary peritoneal cancer . 23. Epidermal Growth Factor ReceptorInhibitors The epidermal growth factor receptor family consistsof four members including EGFR(HER1), HER2, HER3, and HER4 . EGFR overexpression has been reported in 35% to70% of patients with epithelial ovarian cancer . In endometrial cancer, EGFR is overexpressed in 43%to 67% of tumors and is associated with shorteneddisease-free and overall survival . In addition, amplification of the HER2 gene iscommonly found in endometrial carcinoma. 24. Various agents directed against epidermal growthfactor receptors are available .Trastuzumab is a humanized monoclonal antibodythat binds to the extracellular domain of HER2 .Blockade of HER2 affects various molecules thatultimately decreases cell proliferation. Pertuzumab is another humanized monoclonalantibody that binds to a different epitope of HER2compared to trastuzumab. Binding to HER2 prevents dimerization of thereceptor, which is required for its function . 25. Epidermal Growth Factor Receptor Inhibition of EGFR signaling is accomplished by usingeither monoclonal antibodies against the extracellularreceptor or small-molecule inhibitors against theintracellular kinase domain. Both strategies results in inhibition ofphosphorylation or receptor activation. Erlotinib is a potent reversible inhibitor of EGFRtyrosine kinase that blocks receptorautophosphorylation and has been used for thetreatment of ovarian carcinoma. 26. Erlotinib has been used in combination with docetaxel andcarboplatin as first-line treatment after surgicalcytoreduction in patients with ovarian, fallopian tube, andprimary peritoneal cancers . Cetuximab (C225, Erbitux) is a chimerized monoclonalantibody against EGFR. Cetuximab in combination with carboplatin resulted inthree complete (10.7%) and six partial (21.4%) responses in28 patients with recurrent ovarian cancer. Twenty-six of these 28 patients (92.8%) had EGFR-positivetumors. 27. The combination of paclitaxel, carboplatin, and cetuximab for first-line chemotherapy of stage III ovarian cancer patients resulted in progression-free survival of 14.4 months and was therefore not significantly prolonged compared to historical data. 28. Gefitinib (ZD1839 Iressa) is a low molecular weightquinazoline derivative that inhibits the activation of EGFRtyrosine kinase via competitive binding of the ATP-bindingdomain of the receptor. Treatment of patients with recurrent ovarian cancer usingthe combination of gefitinib, carboplatin, and paxitaxelresulted in a high overall response rate of 63% . Interestingly, antitumor responses were observed in 35% ofpatients with platinum-resistant disease compared to a73% response rate in patients with platinum-sensitivedisease. 29. Gefitinib has also been used in combination withtamoxifen. In squamous and adenocarcinoma of the cervix, gefitinib(500 mg/day) treatment resulted in disease stabilization insix of 28 patients (20%) but no clinical responses . Lapatinib is a small-molecule inhibitor of both the HER2and EGFR tyrosine kinase receptor. The rationale for using lapatinib in endometrial carcinomais supported mainly by studies in human cancer cell lines.Its efficacy in endometrial cancer is being investigatedcurrently in clinical trials . 30. HER-2/neu The HER-2/neu receptor is activated by homo- orheterodimerization, resulting in tyrosine phosphorylationand subsequent activation of various downstream signalsthat among other functions control cellular proliferation,migration, and invasion. Trastuzumab is a recombinant, humanized IgG1monoclonal antibody that is specific for the extracellulardomain of HER-2/neu. Binding of the antibody to HER-2/neu prevents activationof the receptor with a subsequent increase of apoptosis invitro and in vivo, impaired DNA damage repair, andinhibition of tumor neovascularization. 31. The HER-2/neu oncogene is overexpressed in severalgynecologic malignancies, including 20% to 30% ofovarian cancers. HER2/neu overexpression is infrequent in cervicalcancer. In uterine papillary serous carcinoma, 12 of 68 (18%)tumors showed HER2/neu overexpression; this wasassociated with a worse overall prognosis . 32. Mitogen-Activated Protein Kinase Pathways The mitogen-activated protein (MAP) kinase cascadesare activated by various cofactors, inflammatorycytokines, and stress. Sorafenib is among the first of the agents withclinically proven efficacy. Sorafenib is a competitiveinhibitor of raf that has been approved for treatmentof renal cell carcinoma and hepatocellular carcinoma. Besides targeting raf, sorafenib also inhibits VEGFR2and VEGFR3, FT3, c-kit, and PDGFR-. 33. The PI3-kinase/Akt/mTOR Pathway The phosphoinositide3-kinase (PI3-kinase)/Akt/mTORpathway is a major oncogenic signaling pathway in variouscancers. Activation of this pathway can be demonstrated in morethan 80% of endometrial cancers, 50% to 70% of epithelialovarian cancers, and approximately 50% of cervicalcancers. Several inhibitors of PI3-kinase/Akt/mTOR signaling arecurrently in clinical trials. Rapamycin or rapamycin analogues, for example, block theactivity of mTOR, a protein complex responsible forincreasing protein synthesis and cellular proliferation. 34. Several mTOR inhibitors, including RAD001 and CCI779, and specific PI3-kinase inhibitors are currently under development in preclinical models and clinical trials. PI3-kinase/Akt/mTOR inhibitors have been used in endometrial cancer with limited benefit. 35. Immunotherapy Failure of functional immunity contributes to thegenesis of virus-associated cancers, such as thosecaused by human papilloma virus (HPV) or Epstein-Barr virus. The greatest success story involving the enhancementof immunity to combat gynecologic cancer is thedevelopment of vaccines against HPV, which are highlyeffective for the prevention of cervical dysplasia andcancer . 36. Some researchers suggest that immune responses aremainly involved in protection from virus-associatedcancers but not other forms of cancer . Cancer is a common disease, and overt immunedeficiency certainly is not necessary for itsdevelopment. However, recent studies have shown that manycancers, including those that are not known to have aviral etiology, are seen with increased frequency inpatients who have dysfunctional immunity. 37. In a recent metaanalysis of cancer incidence in populations known to be immune deficient (e.g., organ-transplant recipients, patients with HIV infection), Grulich and co-workers found an increased incidence of several common cancers, suggesting that impaired immunity can contribute to the development of cancer. 38. Components of the Immune SystemInvolved in Antitumor Responses Various types of human immune responses can targettumor cells. Immune responses can be categorized as humoral orcellular, a distinction based on the observation inexperimental systems that some immune responses couldbe transferred by serum (humoral) and others by cells(cellular). In general, humoral responses refer to antibody responses;antibodies are antigen-reactive, soluble, bifunctionalmolecules composed of specific antigen-binding sitesassociated with a constant region that directs the biologicactivities of the antibody molecule, such as binding toeffector cells or complement activation . 39. Cellular immune responses generally refer to cytotoxicresponses mediated directly by activated immune cellsrather than by the production of antibodies . Nearly all immune responses involve both humoraland cellular components and require the coordinatedactivities of populations of lymphocytes operating inconcert with each other and with antigen-presentingcells. These activities result in various effector functionssuch as antibody production, cytokine secretion, andthe stimulation and expansion of cytotoxic T cells. 40. Cellular interactions involved in immune responsesinclude direct cell-cell contact, as well as cellularinteractions mediated by the secretion of, andresponse to, cytokines. The latter are biologic messenger molecules that playimportant roles in the genesis, amplification, andeffector functions of immune responses. T lymphocytes play a pivotal role by acting as helpercells in the generation of humoral and cellularimmune responses and by acting as effector cells incellular responses. 41. Cytotoxic T cells are effector T cells that can directlyinteract with, and kill, target cells by the release ofcytotoxic molecules and the induction of target cellapoptosis. T-lymphocyte precursors mature into functional Tlymphocytes in the thymus, where they learn to recognizeantigen in the context of the major histocompatibilitycomplex (MHC) molecules of the individual. Most T lymphocytes with the capability of responding toself-antigens are removed during thymic development. 42. T lymphocytes are distinguished from other types oflymphocytes by their biologic activities and by theexpression of distinctive cell surfacemolecules, including the T-cell antigen receptor andthe CD3 molecular complex. T lymphocytes recognize specific antigens byinteractions that involve the T-cell antigen receptor . 43. There are two major subsets of T lymphocytes: T helper/inducercells, which express the CD4 cell surface marker; and Tsuppressor/cytotoxic cells, which express the CD8 marker. CD4 T lymphocytes can provide help to B lymphocytes, resultingin antibody production, and also can act as helper cells for otherT lymphocytes. Much of the helper activity of T lymphocytes is mediated by theproduction of cytokines. CD4 T cells have been further subdivided into TH1 (cellularimmunity/proinflammatory) and TH2 (antibody response-promoting) subsets, based on the pattern of cytokine productionand the biological properties of these cells. 44. Recent studies have identified a subset of T cells thatinhibit autoreactive cells, perhaps acting to preventautoimmune responses . This subset of T cells has been called regulatory T cells.Other recently described T-cell subsets include TH17cells, which are important in driving immune responses tobacteria and fungi . The CD8 T-lymphocyte subset includes cells that arecytotoxic and can directly kill target cells. A major biologic role of such cytotoxic T lymphocytes is thelysis of virus-infected cells. However, cytotoxic Tlymphocytes can directly mediate the lysis of tumor cells. 45. Effector T cells also can contribute to antitumor immuneresponses by producing cytokines, such as tumor necrosisfactor (TNF), that induce tumor cell lysis and can enhanceother antitumor cell effector responses. Both CD4 and CD8 T cells respond to antigen only when itis presented in the context of MHC molecules on antigen-presenting cells or target cells or both. The T-cell receptor on CD4 T cells is restricted toresponding to antigen plus MHC class II molecules; thereceptor on CD8 T-cells is restricted to responding toantigen plus MHC class I molecules. 46. Therefore, provision of effective costimulatory signalsis necessary for the induction of effective antitumorresponses by activated T cells. B lymphocytes are the cells that produce and secreteantibodies, which are antigenbinding molecules . B lymphocytes develop from pre-B cells and, afterexposure to antigen and appropriate activationsignals, differentiate to become plasma cellscellsthat produce large quantities of antibodies. Mature B lymphocytes use cell-surfaceimmunoglobulin molecules as antigen receptors. 47. In addition to producing antibodies, B lymphocytesplay another important role: They can serve as efficientantigen-presenting cells for T lymphocytes. Although the production of antitumor antibodies doesnot appear to play a central role in host antitumorimmune responses, monoclonal antibodies reactivewith tumor-associated antigens have proved to be veryuseful in antitumor therapy, as well as in the detectionof tumors or of tumor-associated molecules. 48. Macrophages and dendritic cells also play key roles inthe generation of adaptive, lymphocyte-mediatedimmune responses by acting as antigen-presentingcells. Helper/inducer (CD4) T lymphocytes, bearing a T-cellreceptor of appropriate antigen and self-specificity, areactivated by antigen-presenting cells that displayprocessed antigen combined with self-MHCmolecules. 49. Antigen-presenting cells also provide costimulatorysignals that are important for the induction of T-lymphocyte activation. In addition to serving as antigen-presentingcells, macrophages can ingest .and killmicroorganisms and act as cytotoxic antitumor killercells. These cells also produce various cytokines, includingIL-1, IL-6, chemokines, IL-10, and TNF, which areinvolved in many immune responses 50. These monocyte-produced cytokines can have directeffects on tumor cell growth and development, both asgrowth-inducing and growth-inhibiting factors. Natural killer (NK) cells are cells that have large granularlymphocytic morphology, do not express the CD3 T-cellreceptor complex, and do not respond to specific antigens.NK cells can lyse target cells, including tumorcells, unrestricted by the expression of antigen or self-MHCmolecules on the target cell. Therefore, NK cells are effector cells in an innate (non-antigen-restricted) immune response and may play a vitalrole in immune responses to tumor cells. The cells that caneffect antibody-dependent cellular cytotoxicity (ADCC) areNKlike cells. 51. Cytokines are soluble mediator molecules thatinduce, enhance, or effect immune responses. Cytokines are produced by various types of cells and playcritical roles not only in immune responses but also inbiologic responses outside of the immune response, suchas hematopoiesis or the acute-phase response. T helper 1(TH1) and TH2 cells, which control the nature ofan immune response by secreting characteristic andmutually antagonistic sets of cytokines (9,10,11), are definedby the cytokines they produce. 52. TH1 clones produce IL-2 and IFN-, whereas TH2clones produce IL-4, IL-5, IL-6, and IL-10. TH1 cytokines promote cellmediated andinflammatory responses, whereas TH2 cytokinesenhance antibody production. Most immune responses involve both TH1 and TH2components. Research has identified CD4-positive T cells thatparticipate in the maintenance of immunologic self-tolerance by actively suppressing the activation andexpansion of self-reactive lymphocytes. 53. These cells are called regulatory T cells, or Treg cells. Tregcells are characterized by the expression of CD25 (the IL-2receptor-chain) and the transcription factor FoxP3. Treg cell activity is thought to be important in preventingthe development of autoimmune diseases. Removal of Treg also may enhance immune responsesagainst infectious agents or cancer. Although much remains to be learned about the role ofTreg activity in antitumor immunity, it is clear that suchcells may play a role in modulating host responses tocancer. 54. Therapeutic Strategies There is great interest in developing effective biologicand immune therapies for gynecologic malignancies. For example, patients with small-volume ormicroscopic residual peritoneal ovarian cancer areattractive candidates for immunotherapy or biologictherapy, especially approaches based on regionalperitoneal immunotherapy or biotherapy. Also, many patients with advanced disease areimmunocompromised, suggesting a role forimmuneenhancing therapeutic approaches. 55. Dysplastic and cancerous cervical epithelial cellsinfected with HPV, an oncogenic virus, also present anattractive target for immune enhancement-basedtherapeutic strategies, including the development oftherapeutic vaccines for HPV. Advances in molecularbiology, biotechnology, immunology, and cytokinebiology have resulted in the availability of manynew, promising immunotherapeutic approaches forgynecologic cancers. 56. Monoclonal Antibodies andAntibody-Based Immunotherapy Monoclonal antibodies have played an important role in both thedevelopment of immunotherapeutic agents and tumor markers. Monoclonal antibodies also have been used for radioimmunodetectionand are being used for treatment. Monoclonal antibodies can potentially induce antitumor responses invarious ways:(i) by complement activation and subsequent tumor cell lysis;(ii) by directly inducing antiproliferative effects, perhaps by interaction with tumor cell surface signaling molecules; (iii) by enhancing the activity of phagocytic cells, which caninteract with immune complexes containing monoclonalantibodies; and (iv) by mediating ADCC via interactions of the Fc portion of monoclonal antibodies with Fc receptors on cells thatmediate ADCC . 57. In addition, monoclonal antibodies can be labeledwith either radioactive particles or antitumor drugsand used to focus these agents onto tumor cells . In fact, some monoclonal antibody-based drugs arecurrently approved and being used for the treatmentof cancer with great success. 58. Several clinical trials have utilized monoclonal antibodiesdirected against ovarian cancer antigens, includingCA125, folate receptor, MUC1 antigen, and tumor-associated glycoprotein 72 . Evidence that CA125 can act as a tumor antigen thatstimulates humoral and cellular immune responses isderived from various in vitro studies and clinical trials. Oregovomab (B43.13) is a murine monoclonal antibody toCA125 that has been used for the treatment of ovariancancer. The antibody binds to circulating CA125, resultingin the formation of immune complexes (antibody-antigencomplexes). 59. These immune complexes are recognized asforeign, mainly because of the murine component. They are taken up by antigen-presentingcells, allowing the processing of the autologous CA125antigen, ultimately leading to induction of CA125-specific antibodies, helper T cells, and cytolytic T cells. 60. the velocity of the rise in CA125 levels at relapse was foundto be a highly significant predictor of postrelapse outcome. Another antibody network-based strategy has employedanti-idiotype vaccines in patients with relapsed ovariancancer. ACA125 is a murine anti-idiotypic antibody that mimics anantigenic epitope on CA125. Therefore, antibodies generated to ACA125 have thepotential to react with antigenic epitopes on CA125, withACA125 serving as an antiidiotype vaccine that wouldenhance immune responses to CA125 . 61. Treatment with ACA125 resulted in both humoral andcellular responses, and those patients who haddetectable anti-ACA125 responses showed a longermean survival time than those who did not developresponses . Abagovomab is an anti-idiotypic antibody that mimicsthe CA125 antigen. The initial results of abagovomab treatment inpatients with ovarian cancer were reported bySabbatini et al. and showed that all patients developedan anti-idiotypic antibody response (Ab3). 62. In addition, the generation of T-cell immunity toCA125 was demonstrated in five patients. Whilepatients had measurable serum CA125 levels in bothtrials, neither trial analyzed CA125 expression in tumortissue. A large international, multicenter trial is underway toinvestigate the effect of abagovomab as consolidationtreatment in patients with ovarian cancer. 63. Adoptive lmmunotherapy Adoptive immunotherapy involves the ex vivoexpansion of antitumor immune cells followed by theadministration of such effector cells. It has providedanother immune system-based approach forantitumor therapy. Adoptive immunotherapy, involving the infusion oflarge numbers of autologous ex vivo-activated immuneeffector cells, has been shown to produce tumorregression in various animal and human tumors. 64. Early approaches used peripheral blood mononuclearcells exposed to IL-2 ex vivo to lead to the generationof lymphokine-activated killer (LAK) cells that arecytotoxic for a variety of tumor cells . adoptive immunotherapy with LAK cells does notappear to be a practical option for the treatment ofovarian cancer. The use of immunotherapy based on ex vivo-stimulated tumor-infiltrating lymphocytes or tumor-associated lymphocytes from ascites, with or withoutadded IL-2, also has been examined in ovarian cancer . 65. Dendritic Cell and Tumor VaccineTherapy Various tumor-associated antigens are potentialimmunogens for tumor vaccines, including (i)differentiation antigens, (ii) new antigens created bymutation of genes encoding host cell proteins, (iii)molecules that are overexpressed on tumor cells(i.e., HER2, NY-ESO-1, CA125), and (iv) viral antigens fromoncogenic viruses (i.e., HPV-encoded antigens) . Experimental tumor vaccine therapy in ovarian cancer hasbeen carried out using the NY-ESO-1 antigen. Nearly halfof epithelial ovarian cancers are NY-ESO-1 positive . 66. Vaccination with a peptide from NY-ESO-1 resulted inthe generation of both cellular and humoral immunityto this antigen, in most vaccinated patients . Vaccines based on HER2 also have been tested inovarian cancer patients, with such treatment resultingin the induction of specific T-cell responses in mostpatients . Human papilloma virusspecifically, HPV subtypes16, 18, 31, and 45has been implicated as the majoretiologic agent in cervical cancer. 67. HPV-infected dysplastic and cancerous cervicalepithelial cells consistently retain and express two ofthe viral genes, E6 and E7, that respectively interactwith and disrupt the function of the p53 andretinoblastoma tumorsuppressor gene products. Factors other than infection with HPV, such as cellularimmune function, play an important role indetermining whether the infection of cervicalepithelial cells regresses or progresses to cancer. 68. This has led to the development of prophylactic andtherapeutic vaccines to HPV, as well as treatmentapproaches based on the enhancement of host immunefunction. Human papilloma virus vaccines have been shown to havean exceptional level of efficacy , clearly reducing theincidence of both HPV-16 and -18 infections and HPV-16and -18-related cervical intraepithelial neoplasia. The HPV vaccines Gardasil and Cerverix use HPV-likeparticles as immunogens to generate neutralizingantibodies for HPV. 69. These findings suggest that HPV-based therapeuticcancer vaccines may also be effective for the control ofcervical cancer . HPV E6 and E7 are attractive antigens for use intherapeutic vaccines because these HPV-encodedproteins are involved in cellular transformation andtherefore are consistently expressed in HPV-positivetumor cells. 70. Dendritic cells are highly effective antigen-presentingcells and play a central role in the induction of bothCD4 and CD8 T-cell responses. Dendritic cells can be pulsed with tumor antigenpeptides or bioengineered to express tumorantigens, allowing them to be used in experimentaltherapies that aim to enhance antitumor immunity. Exposure of T cells to dendritic cells pulsed withovarian cancer-derived antigenic preparations resultedin the generation of cytolytic effector T cells that couldkill autologous tumor cells in vitro . 71. In a phase I clinical trial, Hernando and co-workersshowed that patients with advanced gynecologicalmalignancies could be effectively vaccinated withdendritic cells pulsed with a nontumor testantigen, keyhole limpet hemocyanin (KLH), andautologous tumor antigens. Lymphoproliferative responses to KLH and to tumorlysate stimulation were noted. The treatment wassafe, well tolerated, immunologically active, andgenerally devoid of significant adverse effects. 72. Biologic Response Modifier andCytokine Therapy: Modulation of HostImmunity Most early experimental biologic therapies formetastatic ovarian cancer involved biologic responsemodifiers such as Corynebacterium parvum (a heat-killed, gram-negative anaerobic bacillus), bacillusCalmette-Gurin (BCG), or modifications of theseagents . Exposure to C. parvum resulted in the nonspecificenhancement of host immune responses, includingthe induction of an acute inflammatory response . 73. Biologic response modifier therapy for ovariancancer, including treatment with C. parvum and BCG, wasexamined in several studies. IP treatment with IL-12 in patients with carcinomatosisfrom mesotheliomas, mllerian or gastrointestinalcarcinomas, showed a 10% complete response rate anddisease stabilization in nearly half of the treated patients . In a recent phase II trial, treatment with subcutaneouslyadministered IL-2 and oral retinoic acid was reported toimprove survival in patients who had ovarian cancerresponding to chemotherapy . 74. The recent identification of T-cell subpopulations thathave potent immunoregulatory properties, such asTreg cells and TH17 cells, provides new opportunitiesfor the design of host immune system-modulatingtherapies with the aim of enhancing immuneresponses to cancer. TH17 cells are another recently identified regulatory T-cell subpopulation, characterized by the secretion ofIL-17. They have the ability to modulate Treg activity .