Activation of dendritic cells and induction of T cell responses by HPV 16 L1/E7 chimeric virus-like particles are enhanced by CpG ODN or sorbitol

Chimeric human papillomavirus-like particles, consisting of human papillomavirus (HPV) 16 L1-E7 fusion proteins [HPV 16 L1/E7 chimeric virus-like particles (CVLP)], are a vaccine candidate for treatment and prevention of cervical cancer. Although in preclinical studies CVLPs were shown to induce neutralizing antibodies and L1- and E7-specific T cell responses, the results of a recent clinical trial emphasized the need of improved immunogenicity of CVLPs. Here we studied the interaction of HPV 16 L1/E7 CVLPs with mouse bone marrow-derived dendritic cells (BMDCs) activated with different immune adjuvants. We found that lipopolysaccharides (LPS), unmethylated CpG motifs (CpG ODN) and sorbitol enhanced CVLP-induced stimulation of C57BL/6 mouse BMDCs as revealed by increased levels of CD40, CD80, MHC II and CD54 at the cell surface. CpG ODN and sorbitol also enhanced the presentation of Db-restricted cytotoxic T lymphocyte epitopes to HPV 16 L1- or E7-specific T lymphocytes after loading of CVLPs onto BMDCs. Treatment of BMDCs with CpG ODN in combination with CVLPs improved in vitro priming of naive T lymphocytes by CVLP-loaded BMDCs. In vivo, CVLP-loaded BMDCs were more immunogenic as compared with injection of CVLPs alone. CpG ODN and sorbitol further enhanced priming of antigen-specific T cell responses. Our data demonstrate that CpG ODN- or sorbitol-activated BMDCs substantially increase the immunogenicity of CVLPs. Implementing our results in clinical trial protocols may lead to improved activity of therapeutic HPV vaccines for the treatment of HPV-induced cancer.

HDAC inhibitors trigger apoptosis in HPV-positive cells by inducing the E2F-p73 pathway

Histone deacetylase (HDAC) inhibitors induce an intrinsic type of apoptosis in human papillomavirus (HPV)-positive cells by disrupting the mitochondrial transmembrane potential (deltapsim). Loss of deltapsim was only detected in E7, but not in E6 oncogene-expressing cells. HDAC inhibition led to a time-dependent degradation of the pocket proteins pRb, p107 and p130, releasing 'free' E2F-1 following initial G1 arrest. Inhibition of proteasomal proteolysis, but not of caspase activity rescued pRb from degradation and functionally restored its inhibitory effect on the cyclin E gene, known to be suppressed by pRb-E2F-1 in conjunction with HDAC1. Using siRNA targeted against p53, E2F-1 still triggered apoptosis by inducing the E2F-responsive proapoptotic alpha- and beta-isoforms of p73. These data may determine future therapeutic strategies in which HDAC inhibitors can effectively eliminate HPV-positive cells by an apoptotic route that does not rely on the reactivation of the 'classical' p53 pathway through a preceding shut-off of viral gene expression.

E1 empty set E4 protein of human papillomavirus type 16 associates with mitochondria

The human papillomavirus (HPV) E1 empty set E4 protein is the most abundantly expressed viral protein in HPV-infected epithelia. It possesses diverse activities, including the ability to bind to the cytokeratin network and to DEAD-box proteins, and in some cases induces the collapse of the former. E1 empty set E4 is also able to prevent the progression of cells into mitosis by arresting them in the G(2) phase of the cell cycle. In spite of these intriguing properties, the role of this protein in the life cycle of the virus is not clear. Here we report that after binding to and collapsing the cytokeratin network, the HPV type 16 E1 empty set E4 protein binds to mitochondria. When cytokeratin is not present in the cell, E1 empty set E4 appears associated with mitochondria soon after its synthesis. The leucine cluster within the N-terminal portion of the E1 empty set E4 protein is pivotal in mediating this association. After the initial binding to mitochondria, the E1 empty set E4 protein induces the detachment of mitochondria from microtubules, causing the organelles to form a single large cluster adjacent to the nucleus. This is followed by a severe reduction in the mitochondrial membrane potential and an induction of apoptosis. HPV DNA replication and virion production occur in terminally differentiating cells which are keratin-rich, rigid squamae that exfoliate after completion of the differentiation process. Perturbation of the cytokeratin network and the eventual induction of apoptotic properties are processes that could render these unyielding cells more fragile and ease the exit of newly synthesized HPVs for subsequent rounds of infection.

The regulatory E2 proteins of human genital papillomaviruses are pro-apoptotic

Cervical carcinomas are frequently associated with infection by human papillomaviruses (HPVs). These viruses encode two oncogenes E6 and E7, which promote cell proliferation and immortalization. The viral E2 protein represses transcription of the E6/E7 oncogenes and activates viral DNA replication together with the viral E1 helicase. The E2 protein is specifically inactivated in HPV18-associated carcinoma, suggesting that it may prevent carcinogenic progression. Indeed, E2 was shown to exhibit a strong anti-proliferative action when ectopically expressed in cervical carcinoma cells, as it induces both G1 cell cycle arrest and cell death by apoptosis. While the cell cycle arrest is due to E2-mediated transcriptional repression of the viral oncogenes, the induction of apoptosis appears to be an autonomous function of E2. The amino-terminal transactivation domain (TAD) of the E2 protein is required for its pro-apoptotic activity, but transcriptional transactivation is not involved. E2 induces apoptosis through the extrinsic pathway, involving the initiator caspase 8. In addition, E2 is cleaved by caspases during apoptosis, providing an example of an apoptotic inducer, which is itself a target for caspase cleavage. The cleaved E2 protein exhibits an enhanced apoptotic activity, suggesting that it may participate in an amplification loop. This article reviews our current knowledge of the pro-apoptotic activity of the oncogenic papillomavirus E2 proteins, and discusses the implications for the viral vegetative cycle.

The role of human papillomavirus in oral carcinogenesis

Human papillomavirus (HPV) infection with high-risk types 16 and 18 has widely been reported as one of the prominent mechanisms behind the development of cervical squamous cell carcinoma. Links between HPV and oral cavity cancer have been suggested as well, based on epidemiologic and molecular means, though the association is less well-established. It is likely that HPV plays a role in oral cavity carcinogenesis, though only in a small subset of cases. The difficulty in providing true causal evidence of HPV's role in oral cancer lies in our lack of understanding of the significance of mechanisms by which HPV leads to oral carcinogenesis, as well as limitations in the molecular analysis of HPV. Further studies are necessary for the contribution of HPV in oral cavity malignancy to be better demonstrated.

[Pathology of the Cervix. Introduction to the focal topic "Pathology of the cervix - future developments"]

The incidence of cervical cancer has decreased distinctly. Since the causal connection between HPV infection and cervical cancer was proved, new diagnostic and therapeutic methods have become available. New diagnostic possibilities, in certain situations the determination of HPV, a new vaccination as well as molecular-bio-logical tests will shape the future. However, it must not be forgotten that the number of participants in cervical cancer screening has a bigger impact on the decreasing incidence of cervical cancer than any special diagnostic methods.

[Molecular diagnosis of cervical neoplasia: future potential or academic playground?]

Despite major progress in the reduction of incidence and mortality of cervical carcinoma through systematic screening by cytology, there are areas which deserve further improvement, one of them being the obvious overtreatment of CIN 3 which has to be removed in all patients although the invasive potential is limited to a minority of those lesions. Based on new knowledge of cervical carcinogenesis uncovered in the last few years, new potential targets for an individualized determination of prognostic behaviour may become possible. Infection by high-risk HPV types has been recognized as an essential step in the development of cervical carcinoma. In virally induced cervical carcinogenesis, dysregulation of the cell cycle is induced by an overexpression of the oncogenes E6 and E7. Direct determination of these oncogenes may become possible by mRNA measurements. Other biomarkers of cell cycle dysregulation such as p16 may serve in the future to determine the invasive potential of the precursors of cervical carcinoma. Further discoveries in molecular carcinogenesis may possibly allow to develop new diagnostic markers and possibly therapeutic agents in the future.

Induction of tetrasomy by human papillomavirus type 16 E7 protein is independent of pRb binding and disruption of differentiation

We have demonstrated previously that high-risk human papillomaviruses (HPVs) induce tetrasomy in low-grade squamous intraepithelial lesions of the cervix. In this study we show that the E6 and E7 genes of high-risk HPV-16, but not those of low-risk HPV-6, are independently able to induce tetrasomy when constitutively expressed in proliferating monolayer cultures of primary human keratinocytes. Of seven HPV-16 E7 mutants analysed (H2P, Delta6-10, Delta21-24, C24G, S31G/S32G, A50S and S71I), five were severely impaired in their ability to induce tetrasomy in monolayer and raft culture. Only mutant C24G induced tetrasomy to levels comparable with wild-type E7 in monolayer and raft culture. This mutant shows strongly reduced binding to the retinoblastoma gene product pRb. The casein kinase II phosphorylation defective mutant S31G/S32G induced tetrasomy to levels comparable with wild-type E7 in raft culture, but not in monolayer culture, and induction of tetrasomy did not correlate with raft morphology. These results indicate that pRb protein binding is not required for HPV-16 E7 associated tetrasomy and that tetrasomy is not directly related to the ability of this protein to disrupt keratinocyte differentiation.

Lack of the canonical pRB-binding domain in the E7 ORF of artiodactyl papillomaviruses is associated with the development of fibropapillomas

The L-X-C-X-E pRB-binding motif of papillomavirus (PV) E7 proteins has been implicated in the immortalization and transformation of the host cell. However, sequencing of the complete genomes of bovine papillomavirus type 3 (BPV-3), bovine papillomavirus type 5 (BPV-5), equine papillomavirus (EQPV) and reindeer (Rangifer tarandus) papillomavirus (RPV) supports the notion that the pRB-binding motif is not ubiquitous among E7 proteins in the PV proteome. Key among the animal groups that lack the pRB-binding domain are the artiodactyl PVs, including European elk PV (EEPV), deer PV (DPV), reindeer PV (RPV), ovine PVs types 1 and 2 (OvPV-1 and -2) and bovine PVs 1, 2 and 5 (BPV-1, -2 and -5). Whereas the presence of the pRB-binding domain is normally associated with papillomas, the artiodactyl PVs are marked by the development of fibropapillomas on infection. Previous studies emphasized the role of E5 in the pathogenic mechanism of fibropapilloma development, but correlation between the lack of an E7 pRB-binding domain and the unique pathology of the artiodactyl PVs suggests a more complicated mechanism and an early evolutionary divergence from a pRB-binding ancestor.

Propagation, infection, and neutralization of authentic HPV16 virus

Despite the prevalence of HPV16 in invasive cervical cancers, an in vitro system capable of producing infectious HPV16 is lacking. The organotypic (raft) culture system has allowed for the study of the entire differentiation-dependent life cycle of human papillomaviruses (HPVs). However, the use of this system with the prototype HPV16-containing cell line, W12, has failed to yield infectious virus. Our laboratory has introduced clinically derived HPV16(114/B) genomic DNA into primary keratinocytes, where it subsequently recircularized and maintained episomally at 50-100 copies per cell. Virion morphogenesis occurred after epithelial stratification and differentiation in raft culture. HPV16 virions were isolated that were able to infect keratinocytes in vitro. Infection was neutralized by monoclonal antibodies raised against HPV16 but not by monoclonal antibodies known to neutralize other HPV types.

Genomic polymorphism of human papillomavirus type 52 predisposes toward persistent infection in sexually active women

We investigated the role of human papillomavirus (HPV) type 52 polymorphism in the persistence of HPV infection, which is a predictor for cervical lesions. Cervical samples obtained at 6-month intervals were tested for HPV-52 in 1055 women; 41, 12, and 58 women had persistent, transient, and unclassified HPV-52 infections, respectively. HPV-52 isolates were analyzed by polymerase chain-reaction sequencing of the long control region (LCR), E6, and E7 genes. Although age (odds ratio [OR], 0.90 [95% confidence interval [CI], 0.81-0.99]), nonprototypic LCR (OR, 9.26 [95% CI, 2.1-41.7]), and E6 variant (OR, 7.04 [95% CI, 1.4-37]) were associated, in univariate analysis, with the persistence of HPV-52 infection, a nonprototypic LCR variant was the only independent predictor of it (OR, 14.1 [95% CI, 1.1-200]). In the latter variants, the loss of a binding site for a repressor of HPV expression was associated with the persistence of HPV infection (OR, 7.25 [95% CI, 1.67-31.25]).

Transcriptional profiling of dysplastic lesions in K14-HPV16 transgenic mice using laser microdissection

In the K14-HPV16 transgenic mouse model of human papillomavirus (HPV)-associated squamous cell cancers, HPV16 E6 and E7 oncogenes and E1 and E2 regulatory genes are driven by the K14 keratinocyte-specific promoter. HPV transcription varies within the different layers of the epithelium. The correlation between HPV transcription patterns and disease pathogenesis is not well understood. Understanding these patterns is critical to designing and testing new HPV-specific therapeutic strategies. We examined HPV gene expression in homogenous populations of cells microdissected from the stratum basale, stratum spinosum, and stratum corneum of lesions from the transgenic mice using PALM microlaser technology. RNA extracted from each cell layer was subjected to two-step gene-specific RT-PCR and real-time quantitative nested PCR. To ensure specific amplification of spliced transcripts, the primers used for real-time nested PCR spanned the splice sites. High levels of E2 were detected in the basal and supra-basal layers of hyperplastic and dysplastic lesions. E7 and E6* levels increased significantly over time in stratum basale and stratum spinosum. E6** was expressed at much lower levels. We showed that the transgenic mice express correctly spliced E2 transcripts and are suitable as a preclinical model to test a therapeutic strategy using transcriptional regulation by the E2 protein.

Pathogenesis of human papillomaviruses in differentiating epithelia

Human papillomaviruses (HPV) are the etiological agents of cervical and other anogenital malignancies. Over 100 different types of HPVs have been identified to date, and all target epithelial tissues for infection. One-third of HPV types specifically infect the genital tract, and a subset of these are the causative agents of anogenital cancers. Other HPV types that infect the genital tract induce benign hyperproliferative lesions or genital warts. The productive life cycle of HPVs is linked to epithelial differentiation. Papillomaviruses are thought to infect cells in the basal layer of stratified epithelia and establish their genomes as multicopy nuclear episomes. In these cells, viral DNA is replicated along with cellular chromosomes. Following cell division, one of the daughter cells migrates away from the basal layer and undergoes differentiation. In highly differentiated suprabasal cells, vegetative viral replication and late-gene expression are activated, resulting in the generation of progeny virions. Since virion production is restricted to differentiated cells, infected basal cells can persist for up to several decades or until the immune system clears the infection. The E6 and E7 genes encode viral oncoproteins that target Rb and p53, respectively. During the viral life cycle, these proteins facilitate stable maintenance of episomes and stimulate differentiated cells to reenter the S phase. The E1 and E2 proteins act as origin recognition factors as well as regulators of early viral transcription. The functions of the E5 and E1--E4 proteins are still largely unknown, but these proteins have been implicated in modulating late viral functions. The L1 and L2 proteins form icosahedral capsids for progeny virion generation. The characterization of the cellular targets of these viral proteins and the mechanisms regulating the differentiation-dependent viral life cycle remain active areas for the study of these important human pathogens.

Enhanced oncogenicity of Asian-American human papillomavirus 16 is associated with impaired E2 repression of E6/E7 oncogene transcription

Asian-American (AA) variants of human papillomavirus 16 (HPV-16) are linked to a high incidence of cervical cancer in Mexico, with some evidence strongly suggesting that they are more oncogenic than European (E) variants, including their association with younger women and their higher associated risk of cervical cancer. Differences in the regulation of viral E6/E7 oncogene transcription by the E2 protein may be involved in the higher oncogenicity of AA variants. In E variants, E6/E7 oncogene transcription is repressed by the E2 protein and is frequently up-regulated by the destruction of the E2 gene during viral integration. In contrast, the E2 gene is retained in full in most AA-positive carcinomas, raising the possibility of alternative mechanisms for increasing viral oncogene transcription. The authors investigated whether the higher oncogenicity of AA variants is linked to differences in E6/E7 oncogene transcription and the mechanism of E2 deactivation. E6/E7 and E1/E2 transcripts were explored by RT-PCR in 53 HPV-16-positive cervical carcinomas, 39 retaining (20 European and 19 AA) and 14 having lost (12 European and 2 AA) the E1/E2 genes, and transcription repression activity of the AA E2 genes was tested in four cell lines that constitutively express the β-galactosidase reporter or E6/E7 genes driven by the viral long control region. E6/E7 oncogene transcripts were found in all carcinomas, but only those positive for AA variants with E1/E2 genes had complete E2 transcripts. E2 transcripts were down-regulated by splicing in E-positive carcinomas retaining E1/E2. AA E2 genes were impaired for repression of E6/E7 oncogene transcription in vivo. These results suggest that E6/E7 oncogene expression starts earlier in AA than E variant infections, since E variants need E2 to be destroyed or down-regulated.

Beliefs about the risk factors for cervical cancer in a British population sample

BACKGROUND

The introduction of human papillomavirus (HPV) testing into cervical screening has the potential to alter public perceptions of cervical cancer by making explicit the role of a sexually transmitted virus in its etiology. HPV knowledge has been found to be poor, although there is evidence of public awareness of a link between sexual activity and cervical cancer risk. We explored beliefs about the risk factors for cervical cancer in a large population sample.

METHODS

Face-to-face interviews were carried out with a representative sample of the British population. All participants were asked what they thought increased a women's chances of developing cervical cancer.

RESULTS

The response rate was 71% (n = 1940). The most common single response was 'don't know' (38%). Forty-one percent of respondents mentioned factors relating to sex, but only 14% were aware of a link with sexual transmission and fewer than 1% named HPV. Women and more educated people had better knowledge of the established risk factors. The patterning of risk factor awareness by age varied across risk factors.

CONCLUSIONS

Awareness of the role of a sexually transmitted virus in the etiology of cervical cancer is very low in Britain. Provision of information associated with the introduction of HPV testing could change public perceptions of cervical cancer.

High level HPV-16 E7 oncoprotein expression correlates with reduced pRb-levels in cervical biopsies

High-risk human papillomaviruses (HPVs) are major etiological agents of cervical cancer. Despite excellent epidemiological evidence for a direct role of HPV-16 in cervical carcinogenesis, molecular pathways underlying carcinogenesis in vivo remain obscure. The E7 gene is required for immortalization and maintenance of the transformed phenotype in vitro; however, little is known about its role for tumorigenesis in vivo. The E7 gene codes for an unstable protein the abundance of which in cervical biopsies is unknown. We show here that E7 protein levels strongly increase during cervical carcinogenesis, underlining its fundamental role in cervical cancer. The E7 protein was found predominantly in the nucleus and to a minor extent in the cytoplasm in the cervical cancer cell line Ca Ski in vitro and in invasive cervical carcinoma in situ, suggesting that nuclear resident E7 plays a major role in cervical carcinogenesis in humans. The retinoblastoma protein (pRb) is a major E7-target in vitro. We show here that pRb expression is initially upregulated in LSIL and disappears in later stages concomitant with increased E7 levels, suggesting that E7-driven degradation of pRb is involved in cervical tumorigenesis in humans.

Repression of the human papillomavirus E6 gene initiates p53-dependent, telomerase-independent senescence and apoptosis in HeLa cervical carcinoma cells

Cervical cancer cells express high-risk human papillomavirus (HPV) E6 and E7 proteins. When both HPV oncogenes are repressed in HeLa cervical carcinoma cells, the dormant p53 and retinoblastoma (Rb) tumor suppressor pathways are activated, and the cells undergo senescence in the absence of apoptosis. When the E6 gene is repressed in cells that continue to express an E7 gene, the p53 pathway, but not the Rb pathway, is activated, and both senescence and apoptosis are triggered. To determine the role of p53 signaling in senescence or apoptosis after repression of HPV oncogenes, we introduced a dominant-negative allele of p53 into HeLa cells. Dominant-negative p53 prevented senescence and apoptosis when E6 alone was repressed but did not inhibit senescence when both E6 and E7 were repressed. To determine whether reduced telomerase activity was involved in senescence or apoptosis after E6 repression, we generated HeLa cells stably expressing an exogenous hTERT gene, which encodes the catalytic subunit of telomerase. Although these cells contained markedly elevated telomerase activity and elongated telomeres, hTERT expression did not prevent senescence and apoptosis when E6 alone was repressed. These results demonstrate that when the Rb tumor suppressor pathway is inactivated by the E7 protein, E6 repression activates p53 signaling, which in turn is required for growth inhibition, senescence, and apoptosis. Thus, sustained inactivation of the p53 pathway by the E6 protein is required for maintenance of the proliferative phenotype of HeLa cervical carcinoma cells.

Human papillomavirus frequency in oral epithelial lesions

BACKGROUND

Oral human papillomavirus (HPV) prevalence varies according to geographical occurrence, the type of lesion, and the method of diagnosis. The polymerase chain reaction method (PCR) appears to be more sensitive and can be easily applicable to epidemiologic studies.

OBJECTIVES

To determine the frequency of HPV and its genotypes in oral lesions among patients attending a reference clinic of a university hospital.

METHODS

PCR was performed to identify HPV DNA from samples of oral epithelial lesions in 80 patients. For HPV DNA amplification, MY09/MY11 consensus primers were used and specific genotypes were identified through restriction fragment of length polymorphism (RFLP) pattern.

RESULTS

HPV DNA was present in 11.3% of patients, and the identified genotypes were 6b, MM4 (W13B), and MM9 (PAP238A).

CONCLUSIONS

HPV DNA frequency in patients with oral epithelial lesions was 11.3%. The genotypes MM4 and MM9 are uncommon in oral lesions, and they are characterized as high-risk HPV types in those types of lesions.

Life style, environmental and genetic susceptibility to cervical cancer

We have studied cervical cancer (CC) patients from Venezuela and the US to elucidate the contribution of certain acquired and genetic susceptibility factors to the development of the disease. For acquired susceptibility factors, infection with high risk human papilloma virus (HPV), having multiple sex partners and having early sexual activities are significant risk factors for CC in Venezuela. The latter two are not significant risk factors for the US population. Infection with high risk HPV is a more significant risk factor for the US than the Venezuela populations. On the other hand, cigarette smoking is significantly associated with CC in the US but not the Venezuela populations. From genetic susceptibility factors, polymorphisms in the CYP2E1 and mEH genes are not associated with CC but the GSTM1 null genotype is for the US population. Our study indicates that the same susceptibility factors can have very different roles in the development of the same disease such as CC in different countries. The information is useful for the development of effective but different disease prevention programs for different countries in the control of CC.

Prevalence of papillomavirus infection in women in Ibadan, Nigeria: a population-based study

To investigate the prevalence of and the risk factors for cervical infection with human papillomavirus (HPV) in an inner-city area of Ibadan, Nigeria, we interviewed and obtained a sample of cervical cells from 932 sexually active women aged 15 years or older. A total of 32 different HPV types were identified with an HPV prevalence of 26.3% overall and 24.8% among women without cervical lesions; or age-standardised to the world standard population of 28.3 and 27.3%, respectively. High-risk HPV types predominated, most notably HPV 16, 31, 35 and 58. In all, 33.5% of infections involved more than one HPV type. Unlike most populations studied so far, HPV prevalence was high not only among young women, but also in middle and old age. Single women (odds ratio, OR=2.1; 95% confidence interval, CI=1.1–3.9) and illiterate women (OR=1.7; 95%CI=1.1–2.5) showed increased HPV positivity. Associations were also found with anti-Herpes simplex-2 antibodies (OR=1.6; 95% CI: 1.1–2.1) and with the husband's extramarital relationships (OR=1.6: 95% CI: 1.0–2.6). High prevalence of HPV in all age groups may be a distinctive feature of populations where HPV transmission continues into middle age and cervical cancer incidence is very high.

Investigation into a possible association between oral lichen planus, the human herpesviruses, and the human papillomaviruses

BACKGROUND

Oral lichen planus (OLP) is a chronic relapsing cell-mediated condition of unknown etiology. The purpose of this study was to ascertain if the human herpesviruses (HHVs) or human papillomaviruses (HPVs) act as possible factors or co-factors in the pathogenesis of OLP.

METHODS

Thirty-eight histologically confirmed OLP and 20 normal control buccal mucosa tissue samples were analyzed. Polymerase chain reaction analysis was employed to detect members of the HHV and HPV families.

RESULTS

The Epstein-Barr virus and HHV-7 were detected in a small percentage of tissue samples. However, HPV-16 was detected in 26.3% of OLP samples and 0% of the normal control tissues. The epidermodysplasia verruciformis-related HPV types were detected in 42% of OLP samples and 45% of normal control samples.

CONCLUSION

The results of this study do not suggest a causative role for members of the HHV family in the pathology of OLP. However, a statistical association was found between HPV-16 presence and OLP.

HPV-assoziierte Tonsillenkarzinome

The major risk factors for head and neck squamous cell carcinomas (HNSCC) are considered to be tobacco and alcohol. A link between oncogenic types of the human papilloma virus (HPV) and the risk of HNSCC has been suggested in the literature. However, the causal link is now becoming more firmly established on the basis of recent analyses. About 20% of all HNSCC and more than 50% of tonsillar cancers contain HR-HPV. The causal role of HPV-infection in carcinogenesis and the molecular mechanisms involved could thus far be best elucidated in the case of cervical carcinomas. New insights and increasing evidence for the analogy of HPV-positive HNSCC with cervical cancer are discussed. The definition of HPV-positive HNSCC has become more important due to the implications for risk factors and prognosis.

A case-control study of endogenous hormones and cervical cancer

Both parity and oral contraceptive use are associated with elevated circulating levels of sex hormones, at least transiently, and with increased risk of cervical cancer in human papillomavirus (HPV)-infected women. We directly evaluated whether elevations in the physiologic levels of these hormones predispose to the development of cervical neoplasia. We identified 67 premenopausal and 43 postmenopausal women with cervical intraepithelial neoplasia 2, 3, or cervical cancer (>/=CIN2) diagnosed during enrollment of a population-based cohort of 10 077 women. Four controls, two chosen randomly and two chosen from women testing positive for cancer-associated HPV, were matched to each case on menopausal status, age, days since last menses (pre), or years since menopause (post). Sex hormone-binding globulin, oestradiol, oestrone, oestrone-sulphate, dehydroepiandrosterone sulphate, and progesterone were measured in enrollment plasma. There was no consistent association between the sex hormones and risk of >/=CIN2. Excluding cases with invasive disease had a minimal impact on results. Though this case-control study was based on a well-defined population, it was limited by reliance on a single measure of hormone levels taken at the time of diagnosis. Nonetheless, our results do not support the hypothesis that plasma levels of sex hormones have an important bearing on the risk of cervical neoplasia in HPV-infected women.