Notch-1 associates with IKKalpha and regulates IKK activity in cervical cancer cells.

Notch-1 inhibits apoptosis in some transformed cells through incompletely understood mechanisms. Notch-1 can increase nuclear factor-kappa B (NF-kappaB) activity through a variety of mechanisms. Overexpression of cleaved Notch-1 in T-cell acute lymphoblastic leukemia cells activates NF-kappaB via interaction with the I kappa B kinase (IKK) signalosome. Concomitant activation of the Notch and NF-kappaB pathways has been described in a large series of cervical cancer specimens. Here, we show that wild-type, spontaneously expressed Notch-1 stimulates NF-kappaB activity in CaSki cervical cancer cells by associating with the IKK signalosome through IKKalpha. A significant fraction of tumor necrosis factor (TNF)-alpha-stimulated IkappaB kinase activity in CaSki cells is Notch-1-dependent. In addition, Notch-1 is found in the nucleus in association with IKKalpha at IKKalpha-stimulated promoters and is required for association of IKKalpha with these promoters under basal and TNF-alpha-stimulated conditions. Notch-1-IKKalpha complexes are found in normal human keratinocytes as well, suggesting that IKK regulation is a physiological function of Notch-1. Both Notch-1 and IKKalpha knockdown sensitize CaSki cells to cisplatin-induced apoptosis to equivalent extents. Our data indicate that Notch-1 regulates NF-kappaB in cervical cancer cells at least in part via cytoplasmic and nuclear IKK-mediated pathways.

Programmed death-1 blockade enhances expansion and functional capacity of human melanoma antigen-specific CTLs.

Negative co-stimulatory signaling mediated via cell surface programmed death (PD)-1 expression modulates T and B cell activation and is involved in maintaining peripheral tolerance. In this study, we examined the effects of a fully human PD-1-abrogating antibody on the in vitro expansion and function of human vaccine-induced CD8+ T cells (CTLs) specific for the melanoma-associated antigens glycoprotein 100 (gp100) and melanoma antigen recognized by T cells (MART)-1. PD-1 blockade during peptide stimulation augmented the absolute numbers of CD3+, CD4+, CD8+ and gp100/MART-1 MHC:peptide tetramer+ CTLs. This correlated with increased frequencies of IFN-gamma-secreting antigen-specific cells and augmented lysis of gp100+/MART-1+ melanoma targets. PD-1 blockade also increased the fraction of antigen-specific CTLs that recognized melanoma targets by degranulation, suggesting increased recognition efficiency for cognate peptide. The increased frequencies and absolute numbers of antigen-specific CTLs by PD-1 blockade resulted from augmented proliferation, not decreased apoptosis. Kinetic analysis of cytokine secretion demonstrated that PD-1 blockade increased both type-1 and type-2 cytokine accumulation in culture without any apparent skewing of the cytokine repertoire. These findings have implications for developing new cancer immunotherapy strategies.

A phase II study of Hsp-7 (SGN-00101) in women with high-grade cervical intraepithelial neoplasia.

OBJECTIVE: Approximately 2 million women worldwide are infected with high-risk human papillomaviruses (HPV), resulting in a substantial risk for the development of invasive lower genital malignancies. This study was undertaken to determine the effects of vaccination with a protein encoding a bacterial heat shock protein fused to sequences from the oncogenic E7 protein of HPV-16 in women with high-grade cervical intraepithelial neoplasia. Endpoints included lesion regression, immune response, and viral clearance. METHODS: Twenty-one women were prospectively entered into an IRB-approved Phase II study. All women had biopsy-proven high-grade cervical intraepithelial neoplasia and persistent post-biopsy lesions visible by colposcopy. Four injections of HPV-16 Hsp E7 fusion protein at a dose of 500 mug were given 3 weeks apart after which Loop Electrosurgical Excision of the Transformation Zone (LLETZ) was performed. Immune parameters were evaluated pre-vaccine and at the time of LLETZ, and HPV testing was performed at intervals before and after LLETZ. Study subjects were followed for 1 year after LLETZ. RESULTS: Seven of 20 women (35%) evaluable for response had complete regression of their intraepithelial neoplasia at the time of LLETZ, 1 (5%) had regression to CIN I, 11 (55%) had stable disease and 1 (5%) had progression due to enlargement of her lesion. Immune responses were seen in 9 of the 17 women tested; 5 of the 7 complete responders had an immune response. Only 5 of 21 women had HPV-16 or -18. HPV clearance was not associated with lesion regression. CONCLUSION: Hsp-7 (SGN-00101), at this dose and schedule induced lesion regression in women with high-grade intraepithelial neoplasia. The fact that regression was correlated with immune response suggests that enhancing the immunogenicity of this vaccine may lead to improvement in the rate of lesion eradication.

The impact of anti HPV vaccination on cervical cancer incidence and HPV induced cervical lesions: consequences for clinical management.

Cervical cancer is the second most common cause of cancer-related deaths in women worldwide. Screening for cervical cancer is accomplished utilizing a Pap smear and pelvic exam. While this technology is widely available and has reduced cervical cancer incidence in industrialized nations, it is not readily available in third world countries in which cervical cancer incidence and mortality is high. Development of cervical cancer is associated with infection with high risk types of human papillomavirus (HPV) creating a unique opportunity to prevent or treat cervical cancer through anti-viral vaccination strategies. Several strategies have been examined in clinical trials for both the prevention of HPV infection and the treatment of pre-existing HPV-related disease. Clinical trials utilizing prophylactic vaccines containing virus-like particles (VLPs) indicate good vaccine efficacy and it is predicted that a prophylactic vaccine may be available within the next five years. But, preclinical research in this area continues in order to deal with issues such as cost of vaccination in underserved third world populations. A majority of clinical trials using therapeutic agents which aim to prevent the progression of pre-existing HPV associated lesions or cancers have shown limited efficacy in eradicating established tumors in humans possibly due to examining patients with more advanced-stage cancer who tend to have decreased immune function. Future trends in clinical trials with therapeutic agents will examine patients with early stage cancers or pre-invasive lesions in order to prevent invasive cervical cancer. Meanwhile, preclinical studies in this field continue and include the further exploration of peptide or protein vaccination, and the delivery of HPV antigens in DNA-based vaccines or in viral vectors. Given that cervical cancers are caused by the human papillomavirus, the prospect of therapeutic vaccination to treat existing lesions and prophylactic vaccination to prevent persistent infection with the virus are high and may be implemented in the near future. The consequences for clinical management may include a significant reduction in the frequency of Pap smear screening in the case of prophylactic vaccines, and the availability of less invasive and disfiguring treatment options for women with pre-existing HPV associated lesions in the case of therapeutic vaccines. Implementation of both prophylactic and therapeutic vaccine regimens could result in a significant reduction of health care costs and reduction of worldwide cervical cancer incidence.

Immunodominance and tumor escape.

Cancers in mouse and man express multiple tumor-specific as well as tumor-associated antigens. Immunodominance in the host response to these antigens can result in successive selection of heritable antigen loss variants. Immunodominance may also prevent the development of responses to new tumor-specific antigens that may arise during tumor progression. Some tumor-specific antigens are retained during tumor progression possibly because they are essential for survival of the malignant phenotype. Immunodominance may allow cancer cells to escape even after loss of a single MHC Class I allele because cross-presentation of the retained antigen by this allele that must be expressed on the surrounding antigen presenting cells sustains the immunodominant response. This prevents effective responses to secondary antigens that may remain as potential targets. Immunization with in vitro selected cancer cell variants that lack the immunodominant antigen can break the immunodominance and prevent escape of cancers from host immunity.

T cell infiltration of the prostate induced by androgen withdrawal in patients with prostate cancer.

Manipulations capable of breaking host tolerance to induce tissue-specific T cell-mediated inflammation are of central importance to tumor immunotherapy and our understanding of autoimmunity. We demonstrate that androgen ablative therapy induces profuse T cell infiltration of benign glands and tumors in human prostates. T cell infiltration is readily apparent after 7-28 days of therapy and is comprised predominantly of a response by CD4+ T cells and comparatively fewer CD8+ T cells. Also, T cells within the treated prostate exhibit restricted TCR Vbeta gene usage, consistent with a local oligoclonal response. Recruitment/activation of antigen-presenting cells in treated prostate tissues may contribute to local T cell activation. The induction of T cell infiltration in prostate tissues treated with androgen ablation may have implications for the immunotherapeutic treatment of prostate cancer as well as other hormone-sensitive malignancies, including breast carcinoma.

Eradication of established tumors by vaccination with Venezuelan equine encephalitis virus replicon particles delivering human papillomavirus 16 E7 RNA.

The etiological role of human papillomaviruses (HPV) in cervical and other cancers suggests that therapeutic vaccines directed against requisite viral antigens may eradicate tumors or their precursors. A Venezuelan equine encephalitis (VEE) alphavirus vector delivering the HPV16 E7 RNA was evaluated for antitumor efficacy using a murine E7+ tumor model. Vaccination with VEE replicon particles expressing E7 (E7-VRP) induced class I-restricted CD8+ T-cell responses as determined by IFN-gamma enzyme-linked immunospot (ELISPOT), tetramer, and cytotoxicity assays. E7-VRP vaccination prevented tumor development in all of the mice and effectively eliminated 7-day established tumors in 67% of tumor-bearing mice. The induction of protective T-cell responses was dependent on CD8+, but not CD4+ T cells. Long-lasting T-cell memory responses developed in E7-VRP-vaccinated mice as determined by complete protection from tumor challenge 3 months after the final vaccination. These promising results highlight the potent CD8+ T-cell-mediated antitumor effects elicited by VEE replicon-based vectors and support their further development toward clinical testing against cervical intraepithelial neoplasia or carcinoma.

Murine six-transmembrane epithelial antigen of the prostate, prostate stem cell antigen, and prostate-specific membrane antigen: prostate-specific cell-surface antigens highly expressed in prostate cancer of transgenic adenocarcinoma mouse prostate mice.

To identify genes that are differentially up-regulated in prostate cancer of transgenic adenocarcinoma mouse prostate (TRAMP) mice, we subtracted cDNA isolated from mouse kidney and spleen from cDNA isolated from TRAMP-C1 cells, a prostate tumor cell line derived from a TRAMP mouse. Using this strategy, cDNA clones that were homologous to human six-transmembrane epithelial antigen of the prostate (STEAP) and prostate stem cell antigen (PSCA) were isolated. Mouse STEAP (mSteap) is 80% homologous to human STEAP at both the nucleotide and amino acid levels and contains six potential membrane-spanning regions similar to human STEAP. Mouse PSCA (mPsca) shares 65% homology with human PSCA at the nucleotide and amino acid levels. mRNA expression of mSteap and mPsca is largely prostate-specific and highly detected in primary prostate tumors and metastases of TRAMP mice. Both mSteap and mPsca map to chromosome 5. Another known gene coding for mouse prostate-specific membrane antigen (mPsma) is also highly expressed in both primary and metastatic lesions of TRAMP mice. These results indicate that the TRAMP mouse model can be used to effectively identify genes homologous to human prostate-specific genes, thereby allowing for the investigation of their functional roles in prostate cancer. mSteap, mPsca, and mPsma constitute new tools for preventative and/or therapeutic vaccine construction and immune monitoring in the TRAMP mouse model that may provide insights into the treatment of human prostate cancer.

Tetra-O-methyl nordihydroguaiaretic acid induces G2 arrest in mammalian cells and exhibits tumoricidal activity in vivo.

The transcription inhibitor tetra-O-methyl nordihydroguaiaretic acid (M4N) was found to arrest the proliferation of C3, C33a, CEM-T4, and TC-1 cells in culture at the G2 stage of the cell cycle. Investigation into the mechanism of arrest revealed that M4N reduces mRNA levels and subsequent protein production of the cyclin-dependent kinase CDC2, resulting in the inactivation of the CDC2/cyclin B complex (maturation promoting factor). When injected intratumorally in a C3-cell induced C57bl/6 mouse tumor model system, M4N demonstrated substantial tumoricidal activity that correlated with a reduction in tumor cell CDC2 protein levels. These findings suggest that M4N may be a useful chemotherapeutic agent for the control of unregulated cellular proliferation.

Human T cell responses to endogenously presented HLA-A*0201 restricted peptides of Simian virus 40 large T antigen.

Presence of the simian virus 40 (SV40) has recently been demonstrated in a relatively high percentage of human mesotheliomas and it is associated with the development of these malignancies in pleural cavities. Therefore, we have initiated a study to identify candidate peptides presented by the human HLA-A*0201 molecule for vaccination approaches against SV40 and monitoring of SV40 directed human immune responses. Initial screening of SV40 large T (Tag) domains required for transformation of cells for HLA-A*0201 binding motifs revealed ten possible binding peptides. Screening of these candidate peptides showed that seven of the ten peptides could bind and stabilize HLA-A*0201 molecules. In an in vitro immunization assay the two peptides with the highest binding affinity for HLA-A*0201, Tag aa 396-405 and aa 577-585, were tested for their ability to induce peptide specific cytotoxic T cells in two healthy donors. One donor developed cytotoxic T cells against Tag aa 396-405 and in T cell cultures of both donors Tag aa 577-585 specific T cells were initiated. The T cells against Tag aa 577-585 not only recognized and killed peptide pulsed cells, but, most importantly, SV40 transformed human mesothelial cells. This is the first demonstration of the induction of SV40 specific human cytotoxic T lymphocytes that recognize endogenously processed peptides from SV40. This peptide identification study opens the possibility to investigate immune responses against SV40 in mesothelioma patients and in individuals exposed to SV40.

Pharmacokinetic differences between a T cell-tolerizing and a T cell-activating peptide.

Vaccination with a peptide representing a CTL epitope from the human papillomavirus (HPV)16 E7 protein induces a specific CTL response that prevents the outgrowth of HPV16 E7-expressing tumors. In contrast, vaccination with a peptide encoding an adenovirus type 5 (Ad5) E1A CTL epitope results in CTL tolerance and enhanced growth of an Ad5 E1A-expressing tumor. It is unclear why these peptides induce such opposite effects. To determine whether a difference in pharmacokinetics can explain the functional contrasts, tritiated Ad5 E1A and HPV16 E7 peptides were injected into mice. Results show that the tolerizing peptide spread through the body 16 times faster than the activating peptide and was cleared at least 2 times faster. The HPV16 E7 peptide kinetics correlated with the kinetics of HPV16 E7-specific CTL induction. In contrast, Ad5 E1A peptide injection resulted in physical deletion of preexisting Ad5 E1A-specific CTLs within 24 h after injection. This tolerization occurred at the time when the peptide reached its maximum peptide concentration in the organs. These data suggest that ubiquitous expression of the tolerizing Ad5 E1A peptide within a short period of time causes activation-induced cell death of Ad5 E1A-specific CTLs. Therefore, information on the pharmacokinetics of peptides is vital for the safety and efficacy of peptide-based vaccines.

Human dendritic cells are activated by chimeric human papillomavirus type-16 virus-like particles and induce epitope-specific human T cell responses in vitro.

Human papillomavirus (HPV)-derived chimeric virus-like particles (VLPs) are the leading candidate vaccine for the treatment or prevention of cervical cancer in humans. Dendritic cells (DCs) are the most potent inducers of immune responses and here we show for the first time evidence for binding of chimeric HPV-16 VLPs to human peripheral blood-derived DCS: Incubation of immature human DCs with VLPs for 48 h induced a significant up-regulation of the CD80 and CD83 molecules as well as secretion of IL-12. Confocal microscopy analysis revealed that cell surface-bound chimeric VLPs were taken up by DCS: Moreover, DCs loaded with chimeric HPV-16 L1L2-E7 VLPs induced an HLA-*0201-restricted human T cell response in vitro specific for E7-derived peptides. These results clearly demonstrate that immature human DCs are fully activated by chimeric HPV-16 VLPs and subsequently are capable of inducing endogenously processed epitope-specific human T cell responses in vitro. Overall, these findings could explain the high immunogenicity and efficiency of VLPs as vaccines.

Prospect for immunotherapy of acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is diagnosed in approximately 100000 people worldwide per year and 70% of the patients are children. Most children have a good prognosis, as almost 80% will be cured, however only 30% of adults are cured. Additionally, the current chemotherapies have long-lasting and severe side-effects. These findings indicate that the search for better and safer treatment modalities for ALL is still important. As leukemia directly affects the human immune cells, immunotherapeutic approaches have long been ignored as treatment options for this disease. However, increased knowledge of the immune system has opened new opportunities for immune modulation that could be of benefit to leukemia patients. Several recent advances towards immunotherapy of ALL will be discussed.

Physical interaction of human papillomavirus virus-like particles with immune cells.

Human papillomavirus virus-like particles (HPV VLP) and chimeric VLP are immunogens that are able to elicit potent anti-viral/tumor B and T cell responses. To investigate the immunogenicity of VLP, we determined which cells of the immune system are able to bind HPV-16 VLP. VLP were found to bind very well to human and mouse immune cells that expressed markers of antigen-presenting cells (APC) such as MHC class II, CD80 and CD86, including dendritic cells, macrophages and B cells. mAb blocking studies identified Fc gamma RIII (CD16) as one of the molecules to which the VLP can bind both on immune cells and foreskin epithelium. However, transfection of a CD16(-) cell line with CD16 did not confer binding of VLP. Splenocytes from Fc gamma RIII knockout mice showed a 33% decrease in VLP binding overall and specifically to subsets of APC. These combined data support a role for CD16 as an accessory molecule in an HPV VLP-receptor complex, possibly contributing to the immunogenicity of HPV VLP.

Defined flanking spacers and enhanced proteolysis is essential for eradication of established tumors by an epitope string DNA vaccine.

Loss of immunogenic epitopes by tumors has urged the development of vaccines against multiple epitopes. Recombinant DNA technologies have opened the possibility to develop multiepitope vaccines in a relatively rapid and efficient way. We have constructed four naked DNA-based multiepitope vaccines, containing CTL, Th cell, and B cell epitopes of the human papillomavirus type 16. Here we show that gene gun-mediated vaccination with an epitope-based DNA vaccine protects 100% of the vaccinated mice against a lethal tumor challenge. The addition of spacers between the epitopes was crucial for the epitope-induced tumor protection, as the same DNA construct without spacers was significantly less effective and only protected 50% of the mice. When tested for therapeutic potential, only the epitope construct with defined spacers significantly reduced the size of established tumors, but failed to induce tumor regression. Only after targeting the vaccine-encoded protein to the protein degradation pathway by linking it to ubiquitin, the vaccine-induced T cell-mediated eradication of 100% of 7-day established tumors in mice. The finding that defined flanking sequences around epitopes and protein targeting dramatically increased the efficacy of epitope string DNA vaccines against established tumors will be of importance for the further development of multiepitope DNA vaccines toward clinical application.

Mechanism of immune dysfunction in cancer mediated by immature Gr-1+ myeloid cells.

The mechanism of tumor-associated T cell dysfunction remains an unresolved problem of tumor immunology. Development of T cell defects in tumor-bearing hosts are often associated with increased production of immature myeloid cells. In tumor-bearing mice, these immature myeloid cells are represented by a population of Gr-1(+) cells. In this study we investigated an effect of these cells on T cell function. Gr-1(+) cells were isolated from MethA sarcoma or C3 tumor-bearing mice using cell sorting. These Gr-1(+) cells expressed myeloid cell marker CD11b and MHC class I molecules, but they lacked expression of MHC class II molecules. Tumor-induced Gr-1(+) cells did not affect T cell responses to Con A and to a peptide presented by MHC class II. In sharp contrast, Gr-1(+) cells completely blocked T cell response to a peptide presented by MHC class I in vitro and in vivo. Block of the specific MHC class I molecules on the surface of Gr-1(+) cells completely abrogated the observed effects of these cells. Thus, immature myeloid cells specifically inhibited CD8-mediated Ag-specific T cell response, but not CD4-mediated T cell response. Differentiation of Gr-1(+) cells in the presence of growth factors and all-trans retinoic acid completely eliminated inhibitory potential of these cells. This may suggest a new approach to cancer treatment.

Human T-cell responses to HLA-A-restricted high binding affinity peptides of human papillomavirus type 18 proteins E6 and E7.

Human Papillomaviruses (HPVs) are sexually transmitted pathogens, which are implicated in the etiology of cervical cancer. The early proteins E6 and E7 of HPV have transforming capacity and interfere with the cell cycle control of infected host cells and are essential for the maintenance of the transformed state. Identification of MHC class I-restricted, immunogenic peptides derived from either the E6 or the E7 protein is essential for the design of vaccines as well as the monitoring of clinical trials and immunotherapeutic approaches for the treatment of HPV-18-induced carcinomas. We have determined the binding affinities for all possible 9-mer peptides spanning the entire E6 and E7 amino acid sequence for the HLA-A*0101, HLA-A*0201, HLA-A*0302, HLA-A*1102, and HLA-A*2402101 molecules by a competition assay with reference peptides, thereby establishing the binding peptides as potential cytotoxic T-cell epitopes. From the HLA-A*0201 binding peptides, we selected five E6-derived and one E7-derived peptide with high affinities for HLA-A*0201. These six peptides were tested for their immunogenicity by in vitro immunization assays with purified human CD8+ T cells. We identified three HPV-18 E6-derived peptides (ELTEVFEFA, KTVLELTEV, and KLPDLCTEL) and the E7-derived peptide TLQDIVLHL to be highly immunogenic. Overall, these results will help to design vaccines for the prevention or treatment of HPV-18-induced cervical cancer.

A murine model for the effects of pelvic radiation and cisplatin chemotherapy on human papillomavirus vaccine efficacy.

Therapeutic human papillomavirus (HPV) vaccines for cervical cancer depend on a competent immune system to be effective. However, cancer patients are often found to be immunosuppressed, which could be attributable to prior radiation, chemotherapy, or the tumor burden itself. This study investigated whether pelvic radiation or cisplatin treatment affected the efficacy of an HPV vaccine and how long these effects lasted. Mice were given pelvic radiation, 2 Gy/day to a total dose of 45 Gy, or 5 mg/kg/week of cisplatin for 3 weeks. Mice were then immunized with an HPV-16 peptide vaccine between 0 and 16 weeks after their treatment. An ELISPOT analysis revealed that a reduced level of peptide-specific, IFNgamma-producing spleen cells was present in immunized mice treated previously with pelvic radiation or cisplatin compared with immunized mice that had not been treated. However, when mice were challenged with HPV-16-expressing tumor cells, immunized mice developed no tumors, regardless of prior treatment, whereas nonimmunized mice did develop tumors. Our results suggest that pretreatment with pelvic radiation or cisplatin alone does not prevent the induction of an effective immune response by a peptide vaccine. These data will have important implications for immunotherapeutic treatment of pretreated cancer patients, especially in the adjuvant setting when immunosuppression by tumor burden would be low.

Tracking the common ancestry of antigenically distinct cancer variants.

In the months and years after first diagnosis, cancers often show an increase in their malignancy such as faster growth, resistance to chemo- and/or hormonal therapy, and loss of antigens targeted by immunotherapy. Our objective was to develop a model in which one can track the changes occurring as a result of in vivo immune selection, such as the loss of antigen, the emergence of previously hidden antigens, or the acquisition of new tumor-specific antigens. In this study, we used the primary UV-induced murine tumor 8101, which consists predominantly of regressor tumor cells that express the immunodominant mutant p68 antigen, but this tumor also contains progressor variants that have lost this antigen. To search for tumor-specific antigens on the immune escape progressors, we raised CD8+ T cells specific for these variants. We found that one of the escape variants expressed a previously unrecognized, unique tumor-specific antigen. However, this unique antigen was not readily detectable on any of the other 8101 lines we tested. To prove that these antigenically distinct cancer variants had indeed been derived from the same tumor and neither represented new tumors nor contaminations by other cell lines, we used unique tumor-specific p53 mutations as a lineage-specific marker to demonstrate that these antigenically distinct progressor variants were derived from the 8101 tumor. Because p53 mutations occur very early during UV carcinogenesis and vary from tumor to tumor, they provide convenient reliable markers for tracking the origin of cancers arising after immune selection or immunotherapy.

Cervical cancer vaccines: emerging concepts and developments.

Certain human cancers are linked to infection by oncogenic viruses that are able to cause transformation of the normal host cell into a cancerous cell. Human papillomavirus (HPV) DNA and expression of viral transforming proteins are found in virtually all cervical cancer cells, indicating an important role of this virus in the pathogenesis of the disease. Evidence exists that the immune response to cancer cells can play a major role in determining the outcome of disease. The fact that HPV is a necessary cause for cervical cancer provides a clear opportunity to develop a therapeutic vaccine against the virus to treat patients with cervical cancer at its early and late stages. Development of a prophylactic vaccine for HPV would also reduce the incidence of cervical neoplasias by preventing virus infection. Various candidate HPV vaccines are being developed and tested in animal models and/or in human clinical trials. These HPV vaccines, both preventive and therapeutic, are the subjects of this review.