Molecular cloning and nucleotide sequence analysis of a novel human papillomavirus (Type 82) associated with vaginal intraepithelial neoplasia

High Prevalence of HPV 51 in an Unvaccinated Population and Implications for HPV Vaccines

Human papillomavirus (HPV) is detected in 99.7% of cervical cancers. Current vaccines target types 16 and 18. Prior to vaccination implementation, a prospective cohort study was conducted to determine baseline HPV prevalence in unvaccinated women in Wales; after HPV16 and HPV18, HPV 51 was found to be most prevalent. This study aimed to re-assess the unexpected high prevalence of HPV 51 and consider its potential for type-replacement. Two hundred HPV 51 positive samples underwent re-analysis by repeating the original methodology using HPV 51 GP5+/6+ PCR-enzyme immunoassay, and additionally a novel assay of HPV 51 E7 PCR. Data were correlated with age, social deprivation and cytology. Direct repeat of HPV 51 PCR-EIA identified 146/195 (75.0%) samples as HPV 51 positive; E7 PCR identified 166/195 (85.1%) samples as HPV 51 positive. HPV 51 prevalence increased with cytological grade. The prevalence of HPV 51 in the pre-vaccinated population was truly high. E7 DNA assays may offer increased specificity for HPV genotyping. Cross-protection of current vaccines against less-prevalent HPV types warrants further study. This study highlights the need for longitudinal investigation into the prevalence of non-vaccine HPV types, especially those phylogenetically different to vaccine types for potential type-replacement. Ongoing surveillance will inform future vaccines.

Phylogenetic analysis of Alphapapillomavirus based on L1, E6 and E7 regions suggests that carcinogenicity and tissue tropism have appeared multiple times during viral evolution

Members of the Alphapapillomavirus genus are causative agents for cervix cancer and benign lesions in humans. These viruses are classified according to sequence similarities in their L1 region. Yet, viral carcinogenicity has been associated with variations in the proteins encoded by the E6 and E7 genes. In order to relate evolutionary history with origin of carcinogenicity, we performed phylogenetic reconstructions using both nucleotide and predicted amino acid sequences of the L1, E6 and E7 genes. Whilst phylogenetic analysis of L1 reconstructed genus evolutionary history, phylogenies based on E6 and E7 proteins support the idea that mutations at amino acids S/Tx [V/L] (E6) and LxCxE (E7) might be responsible for carcinogenic potential. These findings indicate that virulence within Alphapapillomavirus have appeared multiple times during evolution. Our results reveal that oncogenic potential is not a monophyletic clade-specific adaptation but might be the result of positive selection on random mutations occurring on proteins involved in host infection during viral diversification.

Classification and evolution of human papillomavirus genome variants: Alpha-5 (HPV26, 51, 69, 82), Alpha-6 (HPV30, 53, 56, 66), Alpha-11 (HPV34, 73), Alpha-13 (HPV54) and Alpha-3 (HPV61)

HPV variants from the same type can be classified into lineages and sublineages based on the complete genome differences and the phylogenetic topologies. We examined nucleotide variations of twelve HPV types within the species Alpha-5 (HPV26, 51, 69, 82), Alpha-6 (HPV30, 53, 56, 66), Alpha-11 (HPV34, 73), Alpha-13 (HPV54) and Alpha-3 (HPV61) by analyzing 1432 partial sequences and 181 complete genomes from multiple geographic populations. The inter-lineage and inter-sublineage mean differences of HPV variants ranged between 0.9-7.3% and 0.3-0.9%, respectively. The heterogeneity and phylogenies of HPV isolates indicate an independent evolutionary history for each type. The noncoding regions were the most variable regions whereas the capsid proteins were relatively conserved. Certain variant lineages and/or sublineages were geographically-associated. These data provide the basis to further classify HPV variants and should foster future studies on the evolution of HPV genomes and the associations of HPV variants with cancer risk.

Prevalence and risk factors for oral HPV infection in young Australians

The prevalence of human papillomavirus (HPV)–associated head and neck cancers is increasing, but the prevalence of oral HPV infection in the wider community remains unknown. We sought to determine the prevalence of, and identify risk factors for, oral HPV infection in a sample of young, healthy Australians. For this study, we recruited 307 Australian university students (18–35 years). Participants reported anonymously about basic characteristics, sexual behaviour, and alcohol, tobacco and illicit drugs use. We collected oral rinse samples from all participants for HPV testing and typing. Seven of 307 (2.3%) students tested positive for oral HPV infection (3 HPV-18, one each of HPV-16, -67, -69, -90), and six of them were males (p = 0.008). Compared to HPV negative students, those with oral HPV infection were more likely to have received oral sex from more partners in their lifetime (p = 0.0004) and in the last year (p = 0.008). We found no statistically significant associations with alcohol consumption, smoking or numbers of partners for passionate kissing or sexual intercourse. In conclusion, oral HPV infection was associated with male gender and receiving oral sex in our sample of young Australians.

An unusual human papillomavirus type 82 detection in laryngeal squamous cell carcinoma: case report and review of literature

Squamous cell carcinoma (SCC) of the larynx is extremely rare in adolescent or younger adult and typically has an aggressive nature. The mechanism of laryngeal oncogenesis is complex and little is known about the role of human papillomaviruses (HPVs) in SCC in young age. HPV infection may occur during birth or latter by oro-genital contact. Most HPV genotypes detected were HPV 6, 11, 16, 18, 33 and 51. Herein, we report a case of invasive laryngeal SCC expressing an HPV 82 in an 18 year-old man with a history of unexplored severe acute dysphonia that started in early childhood.

Pitfalls in the epidemiologic classification of human papillomavirus types associated with cervical cancer using polymerase chain reaction: driver and passenger

Cervical cancer is a common malignancy in women worldwide, and it has now been established that the human papillomavirus (HPV) is both necessary and causal for these lesions. HPV itself is both ubiquitous and markedly heterogeneous but can nevertheless be classified as either a high-risk type or a low-risk type based upon its frequency of detection in cervical cancer. Given that the association between HPV and cervical cancer is causal, the classification of this virus has been strengthened by large-scale epidemiologic studies and is widely accepted across many disciplines. It is evident, however, that cervical cancer is frequently associated with multiple HPV types. Therefore, it is crucial to distinguish causal types of HPV (drivers) from noncausal types (passengers) in cervical lesions. In this review, we highlight the current pitfalls of using polymerase chain reaction methods instead of Southern blot hybridization for detecting HPV and discuss the distinction between driver and passenger HPVs with regard to the viral type, the length of the viral genome, and the levels of viral DNA associated with cervical cancer. Finally, we newly propose three categories of HPV instead of two risk groups, based on similarities between viral genes.

Comparative Analysis of 19 Genital Human Papillomavirus Types with Regard to p53 Degradation, Immortalization, Phylogeny, and Epidemiologic Risk Classification

We have analyzed E6 proteins of 19 papillomaviruses able to infect genital tissue with regard to their ability to degrade p53 and the thus far unknown immortalization potential of the genomes of human papillomaviruses (HPV) 53, 56, 58, 61, 66, and 82 in primary human keratinocytes. E6 proteins of HPV types 16, 18, 33, 35, 39, 45, 51, 52, 56, 58, and 66, defined as high-risk types, were able to induce p53 degradation in vitro, and HPV18-, HPV56-, and HPV58-immortalized keratinocytes revealed markedly reduced levels of p53. In contrast, the E6 proteins of HPV6 and 11 and HPV44, 54, and 61, regarded as possible carcinogenic or low-risk HPV types, respectively, did not degrade p53. Interestingly, the E6 proteins of HPV 53, 70, and 82 inconsistently risk classified in the literature were also found to induce p53 degradation. The genomes of HPV53 and 82 immortalized primary human keratinocytes that revealed almost absent nuclear levels of p53. These data suggest a strict correlation between the biological properties of certain HPV types with conserved nucleotide sequence (phylogeny), which is largely coherent with epidemiologic risk classification. HPV types 16, 18, 33, 35, 39, 45, 51, 52, 56, 58, and 66, generally accepted as high-risk types, behaved in our assays biologically different from HPV types 6, 11, 44, 54, and 61. In contrast, HPV70, regarded as low-risk type, and HPV53 or HPV82, with inconsistent described risk status, were indistinguishable with respect to p53 degradation and immortalization from prototype high-risk HPV types. This could imply that other important functional differences exist between phylogenetically highly related viruses displaying similar biological properties in tissue culture that may affect their carcinogenicity in vivo.

Bowen's carcinoma of the scrotal skin associated with human papillomavirus type 82

We have previously cloned human papillomavirus type 82 (HPV-82) from a vaginal intraepithelial neoplasia, but it is not known whether HPV-82 can induce a cutaneous lesion. A large erosive nodule developed on the scrotum of a 50-year-old Japanese patient. Histopathologically, the lesion was composed of two distinct parts; one part showing changes characteristic of Bowen's disease in the epidermis, and the other showing elongated rete ridges and proliferation of atypical basaloid cells in the dermis. These parts were partially connected, giving the diagnosis of Bowen's carcinoma. Immunohistochemically, HPV capsid antigen was detected only in the nuclei of a few cells on the upper part of the epidermis. HPV-82 was identified in the lesion by blot hybridization and viral DNA was demonstrated in the lesion by in situ hybridization. HPV-82 has tropism for both the skin and the genital regions.

Molecular Analysis of the Effect of Topical Imiquimod Treatment of HPV 2/27/57-Induced Common Warts

Imiquimod is effective in the treatment of genital warts and clinical studies suggest activity against common warts as well. We have analyzed the effect of topical imiquimod on gene expression and virus load in human papilloma virus (HPV) 2/27/57-induced common warts. mRNA was extracted from keratinocyte culture, from normal skin, from three untreated common warts and from three common warts treated topically with 5% imiquimod cream twice daily. Differential gene expression was demonstrated by RT-PCR and by cDNA microarray hybridization. We further analyzed viral DNA content in scales from three superficially pared imiquimod-treated warts by real-time PCR. Comparison of normal skin with wart tissue revealed that HPV 2/27/57 infection led to an induction of IL-6, IL-10 and interferon-gamma inducible protein (IP10) and to an up-regulation of TGF-beta. We could further detect expression of PCTAIRE-3, WNT2B, frizzled-3, notch-2, notch-4 and BRCA2 in normal skin and common warts. Analysis of imiquimod-treated warts demonstrated that imiquimod enhanced IL-6 expression and induced IL-8, GM-CSF, MRP-8 and MRP-14. It could also be shown that imiquimod led to an infiltration of wart tissue with macrophages and to a strong decrease of viral copy number in warts within 3 months of treatment. Our data thus provide molecular proof of principle for imiquimod treatment of cutaneous common warts.

Human papillomavirus genomes in squamous cell carcinomas of the uterine cervix

The association between invasive cervical carcinoma and human papillomavirus (HPV) has now been established beyond doubt, but this is not necessarily a direct-and-effect association. To assess the causality of HPV, we analyzed HPV genomes in squamous cell carcinomas (SCCs) [corrected] of the uterine cervix by both blot hybridization and PCR. Genital HPV sequences were found in 231 (79%) of 294 SCCs by blot hybridization with more than five copies of entire HPV genomes identified in some cases including HPV 16 (92 cases), HPV 58 (32 cases), and HPV 52 (24 cases). By PCR-direct sequence analysis in 250 of 294 SCCs, genital HPV sequences were found in 240 samples (96%). The partial L1 sequences of HPV 16 were identified in 123 cases, and those of HPVs 18 and 31 were found in 24 and 20 cases, respectively. In addition, multiple HPV types were identified in 29 (12%) of 250 SCCs, and the HPV copy number, detected by PCR only, was less than 0.05. Marked discrepancies were therefore evident between the two analytical techniques. In this report, we discuss the causality of HPV for SCC with regard to the length of the viral genome, the amount of viral DNA, and multiple HPVs in single SCCs.

Routine genotyping of human papillomavirus samples in Denmark

In order to examine a sensitive unbiased consensus PCR with routine sequencing for HPV typing, we analysed Danish male and female patients suspected of having an HPV infection. We used the well-characterised nested PCR setting with MY09/MY11 and GP5+/GP6+ primers, followed by routine cycle sequencing. Of 1283 clinical samples from female patients based on suspected HPV infection, we found 379 (29%) negatives and 894 (70%) positives. Samples containing >5000 HPV copies/ml were genotyped by sequencing. Of the 552 HPV genotyped samples from women >15 years of age, 398 were characterised as high-risk types and the remaining 154 as low-risk types. The most commonly found high-risk types were HPV-16, HPV-31, HPV-33, HPV-18, HPV-58, and HPV-52, and the most commonly found low-risk types were HPV-6, HPV-53 and HPV-11. In addition, we observed that other typing assays could not perform as sensitively or accurately as the nested PCR/cycle sequencing method used in this study. For instance, 87 out of 552 genotyped samples could not have been typed correctly in the Hybrid Capture II assay. Of these 87 samples, 46 (53%) were considered as high-risk types.

Identification of six putative novel human papillomaviruses (HPV) and characterization of candidate HPV type 87

Six putative novel human papillomavirus (HPV) types were detected by using general primers for a conserved L1 HPV region in patients examined in gynecologic centers. One of the isolates, detected in samples from 4 patients with koilocytic atypia at cervical cytology (3 of whom were also infected with human immunodeficiency virus type 1), was completely sequenced, identified as a new HPV genotype, and designated candidate HPV87 (candHPV87) by the Reference Center for Human Papillomavirus. candHPV87 shows the classic HPV genome organization and the absence of a functional E5 coding region. Phylogenetic analysis documented that the candHPV87 genome clusters within the A3 group of HPVs, together with HPV61, HPV72, HPV83, HPV84 and candHPV86, which have been completely sequenced, and a number of other putative novel genotypes (two of which are described in this work), which have been partially characterized. To address the growth-enhancing potential of candHPV87, the E6 and E7 putative coding regions were cloned and expressed in tissue cultures. The data indicate that both proteins stimulate cell division in tissue cultures more than those of low-risk HPVs, though not as much as those of HPV16. Taken together, the clinical, molecular, and biological data suggest that the novel papillomavirus characterized in the present study is a low- to intermediate-risk HPV.

Lactobacilli-mediated control of vaginal cancer through specific reactive oxygen species interaction

Klebanoff et al. proposed that hydrogen peroxide-producing lactobacilli and peroxidase in the vagina of healthy women might be responsible for the prevention of vaginosis and also might exert an antitumor effect (1). Based on recent evidence on superoxide anion generation by transformed cells (2,3) and on the potential of myeloperoxidase for selective apoptosis induction in transformed cells (4), a model for specific reactive oxygen species interaction during lactobacilli-mediated tumor control in the vagina is presented here. We propose that peroxidase, which converts hydrogen peroxide into hypochlorous acid, is responsible for creating a microbicidal vaginal milieu by maintaining a balanced, non-toxic, steady state level of the microbicides H(2)O(2)and HOCI. In case individual superoxide anion-producing transformed cells eventually appear in the mucosa they will be driven into apoptosis by interaction of HOCI with superoxide anions which leads to the generation of hydroxyl radicals. Hence selective apoptosis induction in transformed cells represents the key element of lactobacilli-mediated antitumor defense. Since papilloma virus infected cells are resistant to this pathway of apoptosis induction, they are plausible candidates for circumvention of lactobacilli-mediated control of oncogenesis.

Relationships between 80 human papillomavirus genotypes and different grades of cervical intraepithelial neoplasia: association and causality

To clarify the causal relationship between human papillomavirus (HPV) and cervical intraepithelial neoplasia (CIN), we analyzed 386 unfixed biopsy specimens by blot hybridization at Tm -40 degrees C, targeting 38 skin and 42 genital HPVs. By the recognition of PstI, BanI, and MspI cleavage patterns, single genital, but no skin's HPVs were identified with more than 10 copies per cell in 354 CIN (88 CIN I, 94 CIN II, and 172 CIN III). HPVs 40, 42, 43, 54, 62, or 71 was found in 10 CIN I, while HPVs 18, 30, 39, 51, 56, 59, 66, 68, 69, or 82 was found in 35 CIN I, 20 CIN II, or 8 CIN III. On the other hand, HPVs 16, 31, 33, 35, 52, 58, or 67 was identified in 43 CIN I, 74 CIN II, or 164 CIN III. The results are strongly indicative that most genital HPVs have potency to induce CIN I; however, HPV 16 and its closely related types are able to efficiently induce CIN III. We discuss the definition of causal HPV for CIN with regard to viral prevalence and viral load.