Distinct Human Papillomavirus Research Articles

Variant analysis of human papillomavirus type 52 in Iranian women during 2018-2020: A case-control study.

Knowing the regional variants of distinct human papillomavirus (HPV) types is valuable as it can be beneficial for studying their epidemiology, pathogenicity, and evolution. For this reason, the sequence variations of the E6 gene of HPV 52 were investigated among women with normal cervical cytology and premalignant/malignant cervical samples. Sixty-four HPV 52-positive samples were analyzed using semi-nested PCR and sequencing. Our findings showed that all samples belonged to lineage A (61%) or B (39%). Among samples that were infected with the A lineage, sublineages A1 and A2 were detected and sublineage A1 was dominant. No association was found between lineages and stage of disease (p > 0.05). Our results revealed that the A lineage, sublineage A1, and B lineage were common in Iranian women. Nevertheless, more studies with larger sample sizes are required to estimate the pathogenicity risk of HPV 52 lineages in Iranian women with cervical cancer.

Long-read sequencing of oropharyngeal squamous cell carcinoma tumors reveal diverse patterns of high-risk Human Papillomavirus integration.

In North America and in most European countries, Human Papillomavirus (HPV) is responsible for over 70% of oropharyngeal squamous cell carcinomas. The burden of OPSCC, in high-income countries, has been steadily increasing over the past 20 years. As a result, in the USA and in the UK, the burden of HPV-related oropharyngeal squamous cell carcinoma in men has now surpassed that of cervical cancer in women. However, the oncogenic impact of high-risk HPV integration in oropharyngeal squamous cell carcinomas hasn't been extensively studied. The present study aimed to explore the patterns of HPV integration in oropharyngeal squamous cell carcinomas and to assess the feasibility and reliability of long-read sequencing technology in detecting viral integration events in oropharyngeal head and neck cancers. A cohort of eight HPV-positive OPSCC pre-treatment patient tumors (four males and four females), were selected. All patients received a p16INK4A positive OPSCC diagnosis and were treated at the McGill University Health Centre, a quaternary center in Montreal. A minimum of 20mg of tumor tissue was used for DNA extraction. Extracted DNA was subjected to Nanopore long-read sequencing to detect and analyze for the presence of high-risk HPV sequences. PCR and Sanger sequencing experiments were performed to confirm Nanopore long-read sequencing readings. Nanopore long-read sequencing showed that seven out of eight patient samples displayed either integrated or episomal high-risk HPV sequences. Out of these seven samples, four displayed verifiable integration events upon bioinformatic analysis. Integration confirmation experiments were designed for all four samples using PCR-based methods. Sanger sequencing was also performed. Four distinct HPV integration patterns were identified: concatemer chromosomal integration in a single chromosome, bi-chromosomal concatemer integration, single chromosome complete integration and bi-chromosomal complete integration. HPV concatemer integration also proved more common than full HPV integration events. Long-read sequencing technologies can be effectively used to assess HPV integration patterns in OPSCC tumors. Clinically, more research should be conducted on the prognostication value of high-risk HPV integration in OPSCC tumors using long-read sequencing technology.

Characterization of type-specific HPV prevalence in a population of persistent cutaneous warts in Flanders, Belgium

Cutaneous warts are benign skin lesions caused by the human papillomavirus (HPV). Even though they are considered benign, they can have a considerable impact on the quality of life and cause serious illness in certain immunocompromised populations. Studies have shown that the efficacy of wart treatment is dependent on the causative HPV type. Therefore, in this article, we aim to determine the HPV genotype-specific prevalence in cutaneous warts of a Flemish population as part of the Omnivirol-Salycilic acid randomized controlled trial. Swab samples of cutaneous warts (n = 269) were collected during enrollment. The DNA extraction was performed on the automated NucliSENS® easyMAG® system (bioMérieux). The samples were analyzed with two separate in-house PCR assays capable of detecting the most prevalent cutaneous HPV types (i.e. wart-associated HPV qPCR) as well as the most relevant mucosal types (i.e. RIATOL qPCR assay). In total, the type-specific prevalence of 30 distinct HPV genotypes was determined. The beta-globin gene was used as a cellularity control and for viral load quantification. Data concerning wart persistence, previous treatment, wart type, and other relevant wart and patient characteristics was collected through a baseline questionnaire. The study population consisted mostly of persistent warts considering that 98% (n = 263) of the sampled skin lesions were older than six months and 92% (n = 247) had undergone previous treatment. The most prominent wart type was the mosaic verruca plantaris (42%, n = 113). The most prevalent HPV types were cutaneous HPV types 27 (73%, n = 195), 57 (63%, n = 169), and 2 (42%, n = 113). Only 2% (n = 6) of the lesions was HPV negative. The highest median viral loads were observed with HPV27 and 57 (i.e. 6.29E+04 and 7.47E+01 viral copies per cell respectively). The multivariate analysis found significant associations between wart persistence and certain wart types, the number of warts, and HPV genotypes. Based on these findings, persistent warts are more likely to: (1) be verruca vulgaris, verruca plantaris simple or mosaic, (2) to manifest as multiple warts, (3) and to be negative for HPV type 2 or 4. These characteristics can be useful in the clinical setting for future risk stratification when considering treatment triage and management.Trial registration: NCT05862441, 17/05/2023 (retrospectively registered).

Comparison between the Roche Cobas 4800 Human Papillomavirus (HPV), Abbott RealTime High-Risk HPV, Seegene Anyplex II HPV28, and Novel Seegene Allplex HPV28 Assays for High-Risk HPV Detection and Genotyping in Mocked Self-Samples.

Infection with high-risk human papillomavirus (hrHPV) is well recognized as the main cause of cervical cancer. The recently developed Seegene Allplex HPV28 assay is a novel quantitative PCR (qPCR) assay designed to separately detect and quantify 28 distinct HPV genotypes in a fully automated and user-friendly manner. This study evaluated and compared the performance of this new assay with the performance of the Roche Cobas 4800, the Abbott RealTime high-risk HPV, and the Seegene Anyplex II HPV28 assays. A total of 114 mocked self-samples, i.e., semicervical samples collected by gynecologists using the Viba-Brush, were analyzed with all four HPV assays. Agreement in terms of detecting and genotyping HPV was assessed by the mean of the Cohen's kappa (κ) coefficient. Results of all four HPV assays agreed in 85.9% of the cases when using the Abbott RealTime manufacturer's recommended quantification cycle (Cq) cutoff for positivity (<32.00) and 91.2% when using an adapted range (32.00 to 36.00). An intercomparison of the included assays demonstrated an overall agreement ranging from 85.9 to 100.0% (κ = 0.42 to 1.00) when using the manufacturer's guidelines and 92.9 to 100.0% (κ = 0.60 to 1.00) with the adapted range. For all assays, highly significant, strongly positive Pearson correlations were shown between the Cq values of positive test results. This study thereby shows high concordance between results of the included HPV assays on mocked self-samples. Based on these findings, we imply that the novel Allplex HPV28 assay demonstrates a comparable performance to those of available qPCR HPV assays, potentially providing opportunities for the simplification and standardization of future large-scale testing. IMPORTANCE This study proves that the novel Allplex HPV28 assay has a good diagnostic performance in comparison with the well-known, validated, and frequently used Roche Cobas 4800, Abbott RealTime, and Anyplex II HPV28 assays. According to our experience, the novel Allplex HPV28 assay had a user-friendly and automated workflow with short hands-on time, had an open platform which facilitates the use of add-on assays, and provided quick and easy-to-interpret results. Together with its ability to detect and quantify 28 HPV genotypes, the Allplex HPV28 assay could therefore potentially provide opportunities for the simplification and standardization of future diagnostic testing programs.

Translated article] Changes in the Prevalence of Human Papillomavirus Genotypes in Genital Warts Since the Introduction of Prophylactic Vaccines

Background and objectiveGenital warts are caused by the human papillomavirus (HPV), whose genotypes have traditionally been classified as low risk or high risk (oncogenic). The first 2 prophylactic vaccines included the most common genotypes at the time: HPV-6, HPV-11, HPV-16, and HPV-18. The aim of this study was to evaluate the prevalence of HPV types in our setting 10 years after the introduction of HPV vaccines. Material and methodsDescriptive, observational, retrospective study of patients diagnosed with genital warts at the sexually transmitted infection unit of a dermatology department between January 2016 and June 2019. ResultsIn total, 362 patients were diagnosed with genital warts during the study period, and 212 (58.6%) underwent genotyping. Thirty-two distinct HPV types were observed, the most common being HPV-6, HPV-11, HPV-16, and HPV-42. HPV DNA was detected in 93.9% of the samples analyzed, and there were 299 genotypes (mean, 1.5 per patient). Overall, 26.6% of patients had more than a single HPV genotype, while 24.1% had at least 1 high-risk type. No significant associations were found between the presence of high-risk HPV types and any of the study variables. At least 2 of the 4 HPV types targeted in the original vaccines were detected in 94.1% of lesions. ConclusionsCompared to 10 years ago, the prevalences of HPV types included in the first 2 prophylactic vaccines have decreased, while the proportion of patients with at least 1 of the 4 most common types has remained unchanged. We also observed a slight increase in infections with multiple HPV types or at least 1 high-risk type.

Modificación de la prevalencia de genotipos del virus del papiloma humano en los condilomas acuminados tras la instauración de la vacuna profiláctica

Background and objectiveGenital warts are caused by the human papillomavirus (HPV), whose genotypes have traditionally been classified as low risk or high risk (oncogenic). The first 2 prophylactic vaccines included the most common genotypes at the time: HPV-6, HPV-11, HPV-16, and HPV-18. The aim of this study was to evaluate the prevalence of HPV types in our setting 10 years after the introduction of HPV vaccines. Material and methodsDescriptive, observational, retrospective study of patients diagnosed with genital warts at the sexually transmitted infection unit of a dermatology department between January 2016 and June 2019. ResultsIn total, 362 patients were diagnosed with genital warts during the study period, and 212 (58.6%) underwent genotyping. Thirty-two distinct HPV types were observed, the most common being HPV-6, HPV-11, HPV-16, and HPV-42. HPV DNA was detected in 93.9% of the samples analyzed, and there were 299 genotypes (mean, 1.5 per patient). Overall, 26.6% of patients had more than a single HPV genotype, while 24.1% had at least 1 high-risk type. No significant associations were found between the presence of high-risk HPV types and any of the study variables. At least 2 of the 4 HPV types targeted in the original vaccines were detected in 94.1% of lesions. ConclusionsCompared to 10 years ago, the prevalences of HPV types included in the first 2 prophylactic vaccines have decreased, while the proportion of patients with at least 1 of the 4 most common types has remained unchanged. We also observed a slight increase in infections with multiple HPV types or at least 1 high-risk type.

Therapeutic DNA Vaccines against HPV-Related Malignancies: Promising Leads from Clinical Trials.

In 2014 and 2021, two nucleic-acid vaccine candidates named MAV E2 and VGX-3100 completed phase III clinical trials in Mexico and U.S., respectively, for patients with human papillomavirus (HPV)-related, high-grade squamous intraepithelial lesions (HSIL). These well-tolerated but still unlicensed vaccines encode distinct HPV antigens (E2 versus E6+E7) to elicit cell-mediated immune responses; their clinical efficacy, as measured by HSIL regression or cure, was modest when compared with placebo or surgery (conization), but both proved highly effective in clearing HPV infection, which should help further optimize strategies for enhancing vaccine immunogenicity, toward an ultimate goal of preventing malignancies in millions of patients who are living with persistent, oncogenic HPV infection but are not expected to benefit from current, prophylactic vaccines. The major roadblocks to a highly efficacious and practical product remain challenging and can be classified into five categories: (i) getting the vaccines into the right cells for efficient expression and presentation of HPV antigens (fusion proteins or epitopes); (ii) having adequate coverage of oncogenic HPV types, beyond the current focus on HPV-16 and -18; (iii) directing immune protection to various epithelial niches, especially anogenital mucosa and upper aerodigestive tract where HPV-transformed cells wreak havoc; (iv) establishing the time window and vaccination regimen, including dosage, interval and even combination therapy, for achieving maximum efficacy; and (v) validating therapeutic efficacy in patients with poor prognosis because of advanced, recurrent or non-resectable malignancies. Overall, the room for improvements is still large enough that continuing efforts for research and development will very likely extend into the next decade.

Recurrent integration of human papillomavirus genomes at transcriptional regulatory hubs

Oncogenic human papillomavirus (HPV) genomes are often integrated into host chromosomes in HPV-associated cancers. HPV genomes are integrated either as a single copy or as tandem repeats of viral DNA interspersed with, or without, host DNA. Integration occurs frequently in common fragile sites susceptible to tandem repeat formation and the flanking or interspersed host DNA often contains transcriptional enhancer elements. When co-amplified with the viral genome, these enhancers can form super-enhancer-like elements that drive high viral oncogene expression. Here we compiled highly curated datasets of HPV integration sites in cervical (CESC) and head and neck squamous cell carcinoma (HNSCC) cancers, and assessed the number of breakpoints, viral transcriptional activity, and host genome copy number at each insertion site. Tumors frequently contained multiple distinct HPV integration sites but often only one “driver” site that expressed viral RNA. As common fragile sites and active enhancer elements are cell-type-specific, we mapped these regions in cervical cell lines using FANCD2 and Brd4/H3K27ac ChIP-seq, respectively. Large enhancer clusters, or super-enhancers, were also defined using the Brd4/H3K27ac ChIP-seq dataset. HPV integration breakpoints were enriched at both FANCD2-associated fragile sites and enhancer-rich regions, and frequently showed adjacent focal DNA amplification in CESC samples. We identified recurrent integration “hotspots” that were enriched for super-enhancers, some of which function as regulatory hubs for cell-identity genes. We propose that during persistent infection, extrachromosomal HPV minichromosomes associate with these transcriptional epicenters and accidental integration could promote viral oncogene expression and carcinogenesis.

Human papillomaviruses: diversity, infection and host interactions

Human papillomaviruses (HPVs) are an ancient and highly successful group of viruses that have co-evolved with their host to replicate in specific anatomical niches of the stratified epithelia. They replicate persistently in dividing cells, hijack key host cellular processes to manipulate the cellular environment and escape immune detection, and produce virions in terminally differentiated cells that are shed from the host. Some HPVs cause benign, proliferative lesions on the skin and mucosa, and others are associated with the development of cancer. However, most HPVs cause infections that are asymptomatic and inapparent unless the immune system becomes compromised. To date, the genomes of almost 450 distinct HPV types have been isolated and sequenced. In this Review, I explore the diversity, evolution, infectious cycle, host interactions and disease association of HPVs.

Lineage analysis of human papillomavirus type 18 based on E6 region in cervical samples of Iranian women.

Distinct human papillomavirus (HPV) 18 variants are thought to differ in oncogenic potential and geographic distribution. As such, understanding the regional variants of HPV 18 would be of great importance for evolutionary, epidemiological, and biological analysis. In this regard, the sequence variations of E6 gene were investigated to characterize more common variants of HPV 18 in normal cells, premalignant, and malignant samples collected from the cervix. In total, 99 samples of HPV 18 were analyzed by polymerase chain reaction and sequencing. In overall, lineages A was identified in all study subjects, among which sublineage A4 was dominant although the difference observed was not statistically significant with regard to different stages of disease. Sublineage A4 comprised 90.9% of samples and the remaining were belonged to sublineages A1, A2, A3, and A5 at the frequency of 6.1%, 1%, 1%, and 1%, respectively. In conclusion, our findings clearly highlight the sublineage A4 of HPV 18 as the most dominant variant in Iran.

Human papillomavirus genotype distribution in cervical cancer biopsies from Nepalese women

BackgroundCervical cancer (CC) is the leading cause of morbidity and mortality from cancer in Nepalese women. Nearly all cases of CC are caused by infection with certain genotypes of human papillomavirus (HPV). Data on HPV genotype distribution in Nepalese CC patients is sparse. We aimed to determine the distribution of HPV genotypes in biopsies of CC tissue from Nepalese women.MethodsThis study examined 248 archived paraffin-embedded tissue specimens from CC cases from patients of B.P. Koirala Memorial Cancer Hospital, Bharatpur, Chitwan, Nepal. DNA was extracted from the biopsies and HPV detection performed by PCR. HPV genotyping was then carried out by a reverse line hybridization technique capable of identifying 36 distinct HPV genotypes.ResultsMost of the samples were from tumors that had been designated by hospital pathologists as squamous cell carcinoma (77.6%). 165 of the 248 samples contained DNA of sufficient quality for rigorous PCR testing. All the analyzable specimens were positive for HPV. The most common HPV genotypes, in decreasing order of frequency were 16, 18, 45, 33, 52, 56 and 31; most were found as single infections (94.5%). Together, HPV types 16, 18, and 45 were found in 92% of the tumor samples.ConclusionThis study strengthens the knowledge-base of HPV genotype distribution in CC cases in Nepal. Hopefully, this information will be useful to the medical community and public health policy-makers in generating improved HPV-surveillance, −prevention and -treatment strategies in Nepal.

Recurring infection with ecologically distinct HPV types can explain high prevalence and diversity

The high prevalence of human papillomavirus (HPV), the most common sexually transmitted infection, arises from the coexistence of over 200 genetically distinct types. Accurately predicting the impact of vaccines that target multiple types requires understanding the factors that determine HPV diversity. The diversity of many pathogens is driven by type-specific or "homologous" immunity, which promotes the spread of variants to which hosts have little immunity. To test for homologous immunity and to identify mechanisms determining HPV transmission, we fitted nonlinear mechanistic models to longitudinal data on genital infections in unvaccinated men. Our results provide no evidence for homologous immunity, instead showing that infection with one HPV type strongly increases the risk of infection with that type for years afterward. For HPV16, the type responsible for most HPV-related cancers, an initial infection increases the 1-year probability of reinfection by 20-fold, and the probability of reinfection remains 14-fold higher 2 years later. This increased risk occurs in both sexually active and celibate men, suggesting that it arises from autoinoculation, episodic reactivation of latent virus, or both. Overall, our results suggest that high HPV prevalence and diversity can be explained by a combination of a lack of homologous immunity, frequent reinfections, weak competition between types, and variation in type fitness between host subpopulations. Because of the high risk of reinfection, vaccinating boys who have not yet been exposed may be crucial to reduce prevalence, but our results suggest that there may also be large benefits to vaccinating previously infected individuals.

Anal condylomas: predictors of recurrence and progression to high-grade dysplasia/carcinoma in situ.

Condyloma acuminatum is caused by human papilloma virus (HPV) infection. Individuals with condylomata acuminata are at an increased risk for anogenital cancers, mainly anal condylomas with dysplasia are precursors of anal squamous cell carcinoma. There are over 70 distinct HPV subtypes; approximately 35 types are specific for the anogenital epithelium and have varying potentials to cause malignant change, such as cervical or anal cancer (1).

Broadly neutralizing antiviral responses induced by a single-molecule HPV vaccine based on thermostable thioredoxin-L2 multiepitope nanoparticles

Vaccines targeting the human papillomavirus (HPV) minor capsid protein L2 are emerging as chemico-physically robust and broadly protective alternatives to the current HPV (L1-VLP) vaccines. We have previously developed a trivalent L2 vaccine prototype exploiting Pyrococcus furiosus thioredoxin (PfTrx) as a thermostable scaffold for the separate presentation of three distinct HPV L2(20–38) epitopes. With the aim of achieving a highly immunogenic, yet simpler and more GMP-production affordable formulation, we report here on a novel thermostable nanoparticle vaccine relying on genetic fusion of PfTrx-L2 with the heptamerizing coiled-coil polypeptide OVX313. A prototype HPV16 monoepitope version of this nanoparticle vaccine (PfTrx-L2-OVX313; median radius: 8.6 ± 1.0 nm) proved to be approximately 10-fold more immunogenic and with a strikingly enhanced cross-neutralization capacity compared to its monomeric counterpart. Vaccine-induced (cross-)neutralizing responses were further potentiated in a multiepitope derivative displaying eight different L2(20–38) epitopes, which elicited neutralizing antibodies against 10 different HPVs including three viral types not represented in the vaccine. Considering the prospective safety of the PfTrx scaffold and of the OVX313 heptamerization module, PfTrx-OVX313 nanoparticles lend themselves as robust L2-based immunogens with a high translational potential as a 3rd generation HPV vaccine, but also as a novel and extremely versatile peptide-antigen presentation platform.

Subtypes of HPV-Positive Head and Neck Cancers Are Associated with HPV Characteristics, Copy Number Alterations, PIK3CA Mutation, and Pathway Signatures.

There is substantial heterogeneity within human papillomavirus (HPV)-associated head and neck cancer (HNC) tumors that predispose them to different outcomes; however, the molecular heterogeneity in this subgroup is poorly characterized due to various historical reasons. We performed unsupervised gene expression clustering on deeply annotated (transcriptome and genome) HPV(+) HNC samples from two cohorts (84 total primary tumors), including 18 HPV(-) HNC samples, to discover subtypes and characterize the differences between subgroups in terms of their HPV characteristics, pathway activity, whole-genome somatic copy number alterations, and mutation frequencies. We identified two distinct HPV(+) subtypes (namely HPV-KRT and HPV-IMU). HPV-KRT is characterized by elevated expression of genes in keratinocyte differentiation and oxidation-reduction process, whereas HPV-IMU has strong immune response and mesenchymal differentiation. The differences in expression are likely connected to the differences in HPV characteristics and genomic changes. HPV-KRT has more genic viral integration, lower E2/E4/E5 expression levels, and higher ratio of spliced to full-length HPV oncogene E6 than HPV-IMU; the subgroups also show differences in copy number alterations and mutations, in particular the loss of chr16q in HPV-IMU and gain of chr3q and PIK3CA mutation in HPV-KRT. Our characterization of two subtypes of HPV(+) HNC tumors provides valuable molecular level information that point to two main carcinogenic paths. Together, these results shed light on stratifications of the HPV(+) HNCs and will help to guide personalized care for HPV(+) HNC patients. Clin Cancer Res; 22(18); 4735-45. ©2016 AACR.

Abstract 2184: Gene expression analysis of human papillomavirus positive head and neck cancer primary tumor samples reveals two distinct subgroups

Abstract Introduction: Human Papillomavirus (HPV) infection is recognized as a major cause for an increasing percent of oropharyngeal squamous cell carcinomas (OPSCC). Patients with HPV-induced OPSCC have a better prognosis than those who are HPV-negative, which implies distinct molecular mechanisms. However, predicting prognosis with the HPV-positive population remains elusive. In this study, we aimed to characterize molecular aspects of HPV expression, HPV integration, and host gene expression to later correlate with survival and recurrence as those data become available for our study population. Materials and methods: Thirty-six primary head and neck SCC (HNSCC) tumor samples were collected between 2011-2013 at University of Michigan hospital, of which 18 were determined to be HPV+ (type16, 18 or 35). Paired-end RNA-Seq libraries were generated using Illumina HiSeq for all samples. The sequences were aligned to both the human and HPV genome. Gene expression levels were quantified for both human and HPV genes using TopHat2 and HTSeq, and HPV integration events were determined using Virus-seq. Results: Hierarchical clustering of the gene expression levels showed three distinct clusters among the samples. The HPV- samples were first separated from the HPV+ samples, and then there were two robust subgroups within the HPV+ samples. Subsequent analysis revealed one subgroup had significantly higher HPV expression levels than the other (p-value: 0.03; Wilcoxon test). The subgroups were also highly correlated with HPV-integration status (8 of the 16 tumors had at least one identified HPV integration event). Differentially expressed genes between HPV-integration positive and negative samples were found to be enriched for interesting pathways, including “keratinocyte differentiation”, “cell adhesion” and “growth factor binding”, suggesting possible differences in carcinogenesis We also examined the HPV integration sites and found the majority of them were transcription factors. These also include several cancer-related genes, such as “BIRC3”, “CD274” and “PBX1”. One gene, KLF12, contained an integration event in one of our tumors and in one of the 36 HPV+ tumors from The Cancer Genome Atlas (TCGA). Network analysis of the genes harboring an integration event in our population or the TCGA HNSCC population (38 total genes) revealed interactions around p63 and ETS. Conclusion: Our data is an important addition to TCGA HNSCC cohort data, because as opposed to TCGA, we did not enforce selection bias towards large tumor size. With our data, we identified two distinct HPV+ subgroups characterized by RNA-Seq expression levels and strongly correlated with HPV viral expression levels and integration status. A significant portion of the HPV+ tumors (50%) had integrated HPV genome, implying important oncogenic potentials for integration events. Citation Format: Yanxiao Zhang, Lada A. Koneva, Shama Virani, Alisha Virani, Katie M. Rentschler, Thomas E. Carey, Laura S. Rozek, Maureen A. Sartor, the University of Michigan Head and Neck SPORE. Gene expression analysis of human papillomavirus positive head and neck cancer primary tumor samples reveals two distinct subgroups. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2184. doi:10.1158/1538-7445.AM2015-2184

Role of ubiquitin and the HPV E6 oncoprotein in E6AP-mediated ubiquitination

Deregulation of the ubiquitin ligase E6 associated protein (E6AP) encoded by the UBE3A gene has been associated with three different clinical pictures. Hijacking of E6AP by the E6 oncoprotein of distinct human papillomaviruses (HPV) contributes to the development of cervical cancer, whereas loss of E6AP expression or function is the cause of Angelman syndrome, a neurodevelopmental disorder, and increased expression of E6AP has been involved in autism spectrum disorders. Although these observations indicate that the activity of E6AP has to be tightly controlled, only little is known about how E6AP is regulated at the posttranslational level. Here, we provide evidence that the hydrophobic patch of ubiquitin comprising Leu-8 and Ile-44 is important for E6AP-mediated ubiquitination, whereas it does not affect the catalytic properties of the isolated catalytic HECT domain of E6AP. Furthermore, we show that the HPV E6 oncoprotein rescues the disability of full-length E6AP to use a respective hydrophobic patch mutant of ubiquitin for ubiquitination and that it stimulates E6AP-mediated ubiquitination of Ring1B, a known substrate of E6AP, in vitro and in cells. Based on these data, we propose that E6AP exists in at least two different states, an active and a less active or latent one, and that the activity of E6AP is controlled by noncovalent interactions with ubiquitin and allosteric activators such as the HPV E6 oncoprotein.

Integrative analysis of head and neck cancer identifies two biologically distinct HPV and three non-HPV subtypes.

Current classification of head and neck squamous cell carcinomas (HNSCC) based on anatomic site and stage fails to capture biologic heterogeneity or adequately inform treatment. Here, we use gene expression-based consensus clustering, copy number profiling, and human papillomavirus (HPV) status on a clinically homogenous cohort of 134 locoregionally advanced HNSCCs with 44% HPV(+) tumors together with additional cohorts, which in total comprise 938 tumors, to identify HNSCC subtypes and discover several subtype-specific, translationally relevant characteristics. We identified five subtypes of HNSCC, including two biologically distinct HPV subtypes. One HPV(+) and one HPV(-) subtype show a prominent immune and mesenchymal phenotype. Prominent tumor infiltration with CD8(+) lymphocytes characterizes this inflamed/mesenchymal subtype, independent of HPV status. Compared with other subtypes, the two HPV subtypes show low expression and no copy number events for EGFR/HER ligands. In contrast, the basal subtype is uniquely characterized by a prominent EGFR/HER signaling phenotype, negative HPV-status, as well as strong hypoxic differentiation not seen in other subtypes. Our five-subtype classification provides a comprehensive overview of HPV(+) as well as HPV(-) HNSCC biology with significant translational implications for biomarker development and personalized care for patients with HNSCC.

P16INK4a/Ki‐67 co‐expression specifically identifies transformed cells in the head and neck region

p16(INK4a) immunohistochemical overexpression is an overall reliable surrogate marker of human papillomavirus (HPV)-associated head and neck squamous cell carcinomas (HNSCC). However, cases of ambiguous p16(INK4a) overexpression are regularly detected in the head and neck: p16(INK4a) expression can be observed in non-malignant tissue, such as tonsillar crypt epithelium and a proportion of branchial cleft cysts. Additionally, diverse patterns of p16(INK4) expression can complicate interpretation of "p16(INK4a) -positivity". These aspects impede the unrestricted application of p16(INK4a) as a diagnostic marker in the head and neck. We hypothesized that combined detection of p16(INK4a) and the proliferation marker Ki-67 could support clarification of ambiguous p16(INK4a) expression in the head and neck by specifically indicating p16(INK4a) -expressing cells with proliferative activity. p16(INK4a) /Ki-67 co-expression in a combined staining procedure was correlated to distinct p16(INK4a) expression patterns and HPV status (HPV DNA followed by E6*I oncogene mRNA detection) in 147 HNSCC and 50 non-malignant head and neck samples. p16(INK4a) /Ki-67 co-expression only occurred in transformed cells of the head and neck. Co-expression was never detected in non-transformed cells. Combined p16(INK4a) /Ki-67 expression was stringently associated with a diffuse p16(INK4a) expression pattern. All HPV oncogene-expressing HNSCC showed p16(INK4a) /Ki-67 co-expression. We demonstrate that p16(INK4a) /Ki-67 co-expression occurs exclusively in transformed cells of the head and neck. Our findings indicate a substantial impact of combined p16(INK4a) /Ki-67 expression in the assessment of ambiguous p16(INK4a) expression in the head and neck by specifically identifying p16(INK4a) -expressing cells with proliferative activity. This property will be of considerable significance for head and neck histo- and cytopathology.

Oncogenic Viral Prevalence in Invasive Vulvar Cancer Specimens From Human Immunodeficiency Virus–Positive and -Negative Women in Botswana

The primary aim of this study was to describe the prevalence of select oncogenic viruses within vulvar squamous cell carcinoma (VSCC) and their association with human immunodeficiency virus (HIV) status in women in Botswana, where the national HIV prevalence is the third highest in the world. A cross-sectional study of biopsy-confirmed VSCC specimens and corresponding clinical data was conducted in Gaborone, Botswana. Polymerase chain reaction (PCR) and immunohistochemistry (IHC) viral testing were done for Epstein-Barr virus, human papillomavirus (HPV) strains, and Kaposi sarcoma herpesvirus, and PCR viral testing alone was done for John Cunningham virus. Human papillomavirus prevalence by PCR was 100% (35/35) among tested samples. Human papillomavirus type 16 was the most prevalent HPV strain (82.9% by PCR, 94.7% by either PCR or IHC). Kaposi sarcoma herpesvirus prevalence by PCR had a significant association with HIV status (P = 0.013), but not by IHC (P = 0.650). The high burden of HPV, specifically HPV16, in vulvar squamous cell cancer in Botswana suggests a distinct HPV profile that differs from other studied populations, which provides increased motivation for HPV vaccination efforts. Oncogenic viruses Kaposi sarcoma herpesvirus and Epstein-Barr virus were also more prevalent in our study population, although their potential role in vulvar squamous cell cancer pathology is unclear.