Chapter 8: Human papillomavirus and skin cancer

The cutaneous beta human papillomavirus type 8 E6 protein induces CCL2 through the CEBPα/miR-203/p63 pathway to support an inflammatory microenvironment in epidermodysplasia verruciformis skin lesions

Human papillomavirus type 8 (HPV8), a cutaneous genus beta HPV type, has co-carcinogenic potential at sun-exposed sites in patients suffering from the inherited skin disease epidermodysplasia verruciformis (EV). We had previously shown that Langerhans cells responsible for epithelial immunosurveillance were strongly reduced at infected sites and that the HPV8 E7 protein interferes with the CCAAT/enhancer-binding protein (C/EBP)β to suppress the Langerhans cell chemokine CCL20. At the same time, however, we observed that EV lesions are heavily infiltrated with inflammatory immune cells, which is similar to the situation in HPV8 E6 transgenic mice. To identify critical inflammatory factors, we used a broad multiplex approach and found that the monocyte attracting chemokine CCL2 was significantly and strongly induced by HPV8 E6 but not E7-expressing HaCaT cells, which were used as a model for UV-damaged skin keratinocytes. Conditioned media from HPV8 E6-expressing keratinocytes enhanced CCL2-receptor (CCR2)-dependent monocyte recruitment in vitro, and macrophages predominated in the stroma but were also detected in the epidermal compartment of EV lesions in vivo. CCL2 induction by HPV8 E6 was even stronger than stimulation with the proinflammatory cytokine TNF-α, and both HPV8 E6 and TNF-α resulted in substantial suppression of the transcription factor C/EBPα. Using RNAi-mediated knockdown and overexpression approaches, we demonstrated a mechanistic role of the recently identified C/EBPα/miR-203/p63 pathway for HPV8 E6-mediated CCL2 induction at protein and transcriptional levels. Epithelial co-expression of p63 and CCL2 was confirmed in HPV8 E6-expressing organotypic air-liquid interface cultures and in lesional EV epidermis in vivo. In summary, our data demonstrate that HPV8 oncoproteins actively deregulate epidermal immune homeostasis through modulation of C/EBP factor-dependent pathways. While HPV8 E7 suppresses immunosurveillance required for viral persistence, the present study provides evidence that E6 involves the stemness-promoting factor p63 to support an inflammatory microenvironment that may fuel carcinogenesis in EV lesions.

Characteristics of Cervical Cancer Caused by the Human Papillomavirus 18 and Its Genetic Variations in Vietnamese Women

BACKGROUND

The involvement of HPV18 in cervical cancer pathogenesis, as well as its high oncogenic potential and influence on the variation of cervical cancer distribution in different geographical regions, makes assessing the characteristics of cervical cancer and its variants the basis for considering potential carcinogenic HPV18 sequence variations and vaccine strategies.

METHODS

A prospective study was conducted at Vietnam Central Obstetrics Hospital from January 1, 2019 to December 31, 2020. HPV18 infection was confirmed in cervical cancer patients using molecular diagnostics. Nucleotide sequences of the HPV18 E6, E7, and L1 genes were used to analyze genetic variations. The demographic, clinical, and laboratory data of the patients were collected and statistically analyzed.

RESULTS

Among 48 patients with HPV18-infected cervical cancer, 79.2% were between the ages of 35-54; while only 20.8% were < 35 and > 54 years old. 100% of patients have been pregnant at some point in their lives, with ≥3 pregnancies accounting for 83.3%. Patients with cervical cancer caused by HPV18 infection were predominantly in stages 0 and I, with no patients in stages II, III, or IV. A single HPV18 infection generates much more cervical cancer cases than multiple HPV18 infections. Symptoms such as lower abdomen pain, unusual anginal discharge, and vaginal bleeding were observed in both stages 0 and I; however, vaginal bleeding after sex was only detected in women with stage I cervical cancer. Cervicitis, cervical ectropion, and ulcers are reported in cervical status stages 0 and I; however, warts and ulcers were only present in stage I. Magnetic resonance imaging produces far superior outcomes than ultrasound. All cytology and pathology tests confirmed L/HSIL, SCC, AC, and CIS. On the other hand, a single HPV18 infection was associated with a significantly higher risk of L/HSIL, SCC, AC, and CIS than multiple HPV18 infections. Nulceotide sequences of the E6, E7, and L1 genes revealed 20 mutations, including three (E6), five (E7), and twelve (L1) mutations. High-frequency mutations (95.8%-100% of HPV18 samples had mutations) occur at the following positions: C287G - P61P (E6 gene), G5503A - R25Q, C5701G - P91R, C6460G - P344R, C6625G - P399R, and C6842G - P471R (L1 gene). A phylogenetic tree based on the E6/E7/L1 gene sequence revealed that 100% belonged to A lineage, with 97.9% belonging AA (Asian Amerindian - A1) and 2.1% belonging to the E (European - A5).

CONCLUSION

Patients with a single HPV18 infection have a higher risk of cervical cancer than those infected with HPV18 and other high-risk strains simultaneously. HPV18 single-infection, on the other hand, had considerably higher incidences of L/HSIL, SCC, AC, and CIS than HPV18 co-infection. The HPV18 strain that was found in Vietnam belonged to lineage A (A1 and A5), which contains several oncogene mutations.

The Debate between the Human Microbiota and Immune System in Treating Aerodigestive and Digestive Tract Cancers: A Review

The human microbiota comprises a group of microorganisms co-existing in the human body. Unbalanced microbiota homeostasis may impact metabolic and immune system regulation, shrinking the edge between health and disease. Recently, the microbiota has been considered a prominent extrinsic/intrinsic element of cancer development and a promising milestone in the modulation of conventional cancer treatments. Particularly, the oral cavity represents a yin-and-yang target site for microorganisms that can promote human health or contribute to oral cancer development, such as Fusobacterium nucleatum. Moreover, Helicobacter pylori has also been implicated in esophageal and stomach cancers, and decreased butyrate-producing bacteria, such as Lachnospiraceae spp. and Ruminococcaceae, have demonstrated a protective role in the development of colorectal cancer. Interestingly, prebiotics, e.g., polyphenols, probiotics (Faecalibacterium, Bifidobacterium, Lactobacillus, and Burkholderia), postbiotics (inosine, butyrate, and propionate), and innovative nanomedicines can modulate antitumor immunity, circumventing resistance to conventional treatments and could complement existing therapies. Therefore, this manuscript delivers a holistic perspective on the interaction between human microbiota and cancer development and treatment, particularly in aerodigestive and digestive cancers, focusing on applying prebiotics, probiotics, and nanomedicines to overcome some challenges in treating cancer.

Beta human papillomavirus 8E6 promotes alternative end joining

Double strand breaks (DSBs) are one of the most lethal DNA lesions in cells. The E6 protein of beta-human papillomavirus (HPV8 E6) impairs two critical DSB repair pathways: homologous recombination (HR) and non-homologous end joining (NHEJ). However, HPV8 E6 only delays DSB repair. How DSBs are repaired in cells with HPV8 E6 remains to be studied. We hypothesize that HPV8 E6 promotes a less commonly used DSB repair pathway, alternative end joining (Alt-EJ). Using CAS9-based Alt-EJ reporters, we show that HPV8 E6 promotes Alt-EJ. Further, using small molecule inhibitors, CRISPR/CAS9 gene knockout, and HPV8 E6 mutant, we find that HPV8 E6 promotes Alt-EJ by binding p300, an acetyltransferase that facilitates DSB repair by HR and NHEJ. At least some of this repair occurs through a subset of Alt-EJ known as polymerase theta dependent end joining. Finally, whole genome sequencing analysis showed HPV8 E6 caused an increased frequency of deletions bearing the microhomology signatures of Alt-EJ. This study fills the knowledge gap of how DSB is repaired in cells with HPV8 E6 and the mutagenic consequences of HPV8 E6 mediated p300 destabilization. Broadly, this study supports the hypothesis that beta-HPV promotes cancer formation by increasing genomic instability.

Human papillomavirus in the setting of immunodeficiency: Pathogenesis and the emergence of next-generation therapies to reduce the high associated cancer risk

Human papillomavirus (HPV), a common sexually transmitted virus infecting mucosal or cutaneous stratified epithelia, is implicated in the rising of associated cancers worldwide. While HPV infection can be cleared by an adequate immune response, immunocompromised individuals can develop persistent, treatment-refractory, and progressive disease. Primary immunodeficiencies (PIDs) associated with HPV-related disease include inborn errors of GATA, EVER1/2, and CXCR4 mutations, resulting in defective cellular function. People living with secondary immunodeficiency (e.g. solid-organ transplants recipients of immunosuppression) and acquired immunodeficiency (e.g. concurrent human immunodeficiency virus (HIV) infection) are also at significant risk of HPV-related disease. Immunocompromised people are highly susceptible to the development of cutaneous and mucosal warts, and cervical, anogenital and oropharyngeal carcinomas. The specific mechanisms underlying high-risk HPV-driven cancer development in immunocompromised hosts are not well understood. Current treatments for HPV-related cancers include surgery with adjuvant chemotherapy and/or radiotherapy, with clinical trials underway to investigate the use of anti-PD-1 therapy. In the setting of HIV co-infection, persistent high-grade anal intraepithelial neoplasia can occur despite suppressive antiretroviral therapy, resulting in an ongoing risk for transformation to overt malignancy. Although therapeutic vaccines against HPV are under development, the efficacy of these in the setting of PID, secondary- or acquired- immunodeficiencies remains unclear. RNA-based therapeutic targeting of the HPV genome or mRNA transcript has become a promising next-generation therapeutic avenue. In this review, we summarise the current understanding of HPV pathogenesis, immune evasion, and malignant transformation, with a focus on key PIDs, secondary immunodeficiencies, and HIV infection. Current management and vaccine regimes are outlined in relation to HPV-driven cancer, and specifically, the need for more effective therapeutic strategies for immunocompromised hosts. The recent advances in RNA-based gene targeting including CRISPR and short interfering RNA (siRNA), and the potential application to HPV infection are of great interest. An increased understanding of both the dysregulated immune responses in immunocompromised hosts and of viral persistence is essential for the design of next-generation therapies to eliminate HPV persistence and cancer development in the most at-risk populations.

Enhanced Spontaneous Skin Tumorigenesis and Aberrant Inflammatory Response to UVB Exposure in Immunosuppressed Human Papillomavirus Type 8‒Transgenic Mice

Human papillomaviruses (HPVs) from the beta genus are commensal viruses of the skin usually associated with asymptomatic infection in the general population. However, in individuals with specific genetic backgrounds, such as patients with epidermodysplasia verruciformis, or those with immune defects, such as organ transplant recipients, they are functionally involved in sunlight-induced skin cancer development, mainly keratinocyte carcinoma. Despite their well-established protumorigenic role, the cooperation between β-HPV infection, impaired host immunosurveillance, and UVB exposure has never been formally shown in animal models. In this study, by crossing skin-specific HPV8-transgenic mice with Rag2-deficient mice, we have generated a preclinical mouse model, named Rag2^‒/‒:K14-HPV8. These mice display an unhealthy skin phenotype and spontaneously develop papilloma-like lesions spreading to the entire skin much more rapidly compared with Rag2^+/+:K14-HPV8 mice. Exposure to low doses of UVB radiation is sufficient to trigger severe skin inflammation in Rag2^‒/‒:K14-HPV8 but not in Rag2^+/+:K14-HPV8 mice. Their inflamed skin very much resembled that observed in cutaneous field cancerization in organ transplant recipients, showing high levels of UVB-damaged cells, enhanced production of proinflammatory cytokines, and mast cell recruitment to the dermis. Overall, this immunocompromised HPV8-transgenic mouse model shows that the coexistence of immune defects, β-HPV, and UVB exposure promotes skin cancer development.

Development of immunodiagnostic tools for in situ investigation of Ovis aries papillomavirus 3 (OaPV3)

Cutaneous squamous cell carcinoma (cSCC) is a malignant lesion characterized by proliferation and transformation of keratinocytes in the epidermis and infiltrating derma. cSCC is reported in domestic and wild animal species, worldwide. The occurrence and development of cSCC rely on synergic multifactorial conditions, most importantly sunlight exposure and Papillomavirus (PV) infection. In sheep, the development of such lesions represents a threat both to animal welfare and milk production. Ovis aries papillomavirus 3 (OaPV3) is the main cSCC viral determinant and oncogenic properties of viral E6 and E7 proteins were preliminarily investigated. However, E6 and E7 role and mechanisms resulting in cSCC have not been fully clarified, mainly due to the lack specific immunological tools, such as antibodies for in situ detection of ovine papillomavirus. This paper reports the development of specific serological tools for the investigation of OaPV3 pathogenicity, and their preliminary use to screen 4 ovine cSSC formalin-fixed paraffin embedded tissues. Relevance of immunological tools to investigation of viral biological properties and diagnosis are also discussed.

A broadly protective vaccine against cutaneous human papillomaviruses

Skin colonization by human papillomavirus (HPV) is typically related to inconspicuous cutaneous infections without major disease or complications in immunocompetent individuals. However, in immunosuppressed patients, especially organ transplanted recipients, cutaneous HPV infections may cause massive, highly spreading and recurrent skin lesions upon synergism with UV-exposure. Current HPV prophylactic vaccines are not effective against cutaneous HPV types (cHPV). By applying a modular polytope-based approach, in this work, we explored different vaccine candidates based on selected, tandemly arranged cHPV-L2 epitopes fused to thioredoxin (Trx) as a scaffold protein. Upon conversion to heptameric nanoparticles with the use of a genetically fused oligomerization domain, our candidate Trx-L2 vaccines induce broadly neutralizing immune responses against 19 cHPV in guinea pigs. Similar findings were obtained in mice, where protection against virus challenge was also achieved via passive transfer of immune sera. Remarkably, immunization with the candidate cHPV vaccines also induced immune responses against several mucosal low- and high-risk HPV types, including HPV16 and 18. Based on cumulative immunogenicity data but also on ease and yield of production, we identified a lead vaccine candidate bearing 12 different cHPV-L2 epitopes that holds great promise as a scalable and GMP production-compatible lead molecule for the prevention of post-transplantation skin lesions caused by cHPV infection.

Skin cancer risk factors among Black South Africans-The Johannesburg Cancer Study, 1995-2016

BACKGROUND

The Black population has lower skin cancer incidence compared to White, Indian/Asian, and Mixed-race populations in South Africa; however, skin cancer still exists in the Black population. The aim of this study is to identify risk factors associated with skin cancer among Black South Africans.

MATERIALS AND METHODS

A case-control study was conducted. Cases were patients with keratinocyte cancers (KCs) and/or melanoma skin cancers (MSCs) and controls were cardiovascular patients. Sociodemographic exposures, environmental health variables, smoking, and HIV status were assessed. Stepwise logistic regression was used to identify risk factors associated with KCs and MSCs.

RESULTS

The KCs histological subtypes showed that there were more squamous cell carcinomas (SCCs) (78/160 in females, and 72/160 in males) than basal cell carcinomas (BCCs). The SCC lesions were mostly found on the skin of the head and neck in males (51%, 38/72) and on the trunk in females (46%, 36/78). MSC was shown to affect the skin of the lower limbs in both males (68%, 27/40) and females (59%, 36/61). Using females as a reference group, when age, current place of residency, type of cooking fuel used, smoking, and HIV status were adjusted for, males had an odds ratio (OR) of 2.04 for developing KCs (confidence interval [CI]: 1.08-3.84, p = .028). Similarly, when age, current place of residency, and place of cooking (indoors or outdoors) were adjusted for, males had an OR of 2.26 for developing MSC (CI: 1.19-4.29, p = .012).

CONCLUSIONS

Differences in the anatomical distribution of KCs by sex suggest different risk factors between sexes. There is a positive association between being male, smoking, rural dwelling, and a positive HIV status with KCs and being male and rural dwelling with MSC. The rural dwelling was a newly found association with skin cancer and warrants further investigation.

E6/E7 from Beta-2-HPVs 122, 38b, and 107 possess transforming properties in a fibroblast model in vitro

Beta-2 Human papillomaviruses 38b, 107, and 122 have been frequently found in cervical cancer samples in western Mexico. Because their E6/E7 genes functions are not fully elucidated, we deepen into their transformation capabilities. To achieve this goal, primary human fibroblasts (FB) were transduced with E6/E7 genotype-specific viral particles. Additionally, E6/E7 from HPVs 16 and 18 were included as controls. All E6/E7-cell models increased their lifespan; however, it is important to highlight that FB-E6/E7-122 showed growth as accelerated as FB-E6/E7-16 and 18. Furthermore, both FB-E6/E7-38b and 122 exhibited abilities to migrate, and FB-E6/E7-122 presented high invasive capacity. On the other hand, ΔNp73 expression was found in all cell models, except for FB-pLVX (empty-vector). Finally, RNAseq found differentially expressed genes enriched in signaling pathways related to cell cycle, epithelial-mesenchymal transition, and cancer, among others. This study shows for the first time, the great transformative potential that genotypes of the Beta-2 also possess, especially HPV122. These Beta-2 HPVs can modulate some of the genes that are well known to be regulated by Alpha-HPVs, however, they also possess alternative strategies to modulate diverse signaling pathways. These data support the idea that Beta-2 HPVs should play an important role in co-infections with Alpha-HPV during carcinogenesis.

Beta-Genus Human Papillomavirus 8 E6 Destabilizes the Host Genome by Promoting p300 Degradation

The beta genus of human papillomaviruses infects cutaneous keratinocytes. Their replication depends on actively proliferating cells and, thus, they conflict with the cellular response to the DNA damage frequently encountered by these cells. This review focus on one of these viruses (HPV8) that counters the cellular response to damaged DNA and mitotic errors by expressing a protein (HPV8 E6) that destabilizes a histone acetyltransferase, p300. The loss of p300 results in broad dysregulation of cell signaling that decreases genome stability. In addition to discussing phenotypes caused by p300 destabilization, the review contains a discussion of the extent to which E6 from other β-HPVs destabilizes p300, and provides a discussion on dissecting HPV8 E6 biology using mutants.

Cervical dysplasia in a patient with inherited epidermodysplasia verruciformis-A mere coincidence?

Epidermodysplasia verruciformis (EV) is a rare inherited or acquired genodermatosis caused by increased susceptibility to infection by the beta subtypes of human papillomavirus (HPV). The co-occurrence of EV with high-risk (HR) HPV infection leading to cervical dysplasia is unreported in the literature to date. We report a patient with inherited EV who developed extensive anogenital and cervical dysplasia linked to concurrent HR-HPV infection. Literature review suggests that there is a negative correlation of cervical dysplasia and cervical cancer with EV, which suggests that this patient's presentation and course are exceptional.

In Vitro Organotypic Systems to Model Tumor Microenvironment in Human Papillomavirus (HPV)-Related Cancers

Despite the well-known role of chronic human papillomavirus (HPV) infections in causing tumors (i.e., all cervical cancers and other human malignancies from the mucosal squamous epithelia, including anogenital and oropharyngeal cavity), its persistence is not sufficient for cancer development. Other co-factors contribute to the carcinogenesis process. Recently, the critical role of the underlying stroma during the HPV life cycle and HPV-induced disease have been investigated. The tumor stroma is a key component of the tumor microenvironment (TME), which is a specialized entity. The TME is dynamic, interactive, and constantly changing—able to trigger, support, and drive tumor initiation, progression, and metastasis. In previous years, in vitro organotypic raft cultures and in vivo genetically engineered mouse models have provided researchers with important information on the interactions between HPVs and the epithelium. Further development for an in-depth understanding of the interaction between HPV-infected tissue and the surrounding microenvironment is strongly required. In this review, we critically describe the HPV-related cancers modeled in vitro from the simplified ‘raft culture’ to complex three-dimensional (3D) organotypic models, focusing on HPV-associated cervical cancer disease platforms. In addition, we review the latest knowledge in the field of in vitro culture systems of HPV-associated malignancies of other mucosal squamous epithelia (anogenital and oropharynx), as well as rare cutaneous non-melanoma associated cancer.

Investigation of viral etiology in potentially malignant disorders and oral squamous cell carcinomas in non-smoking, non-drinking patients

Head and neck squamous cell carcinomas (HNSCC) are the seventh most frequent cancers. Among HNSCCs, oral squamous cell carcinomas (OSCCs) include several anatomical locations of the oral cavity, but exclude the oropharynx. The known risk factors for OSCCs are mainly alcohol consumption and tobacco use for at least 75-80% of cases. In addition to these risk factors, Human papillomavirus (HPV) types 16 and 18, classified as high-risk (HR) HPV genotypes, are considered as risk factors for oropharyngeal cancers, but their role in the development of OSCC remains unclear. We tested the hypothesis of viral etiology in a series of 68 well-characterized OSCCs and 14 potentially malignant disorders (PMD) in non-smoking, non-drinking (NSND) patients using broad-range, sensitive molecular methodologies. Deep-sequencing of the transcriptome did not reveal any vertebrate virus sequences other than HPV transcripts, detected in only one case. In contrast, HPV DNA was detected in 41.2% (28/68) and 35.7% (5/14) of OSCC and PMD cases, respectively. Importantly, 90.9% (30/33) of these belonged to the Betapapillomavirus genus, but no viral transcripts were detected. Finally, high-throughput sequencing revealed reads corresponding to transcripts of the Trichomonas vaginalis virus (TVV), which were confirmed by RT-PCR in two OSCCs. Our results strongly suggest that Alphapapillomavirus genotypes classified as HR are not involved in the development of OSCCs in NSND patients and that known oncogenic infectious agents are absent in these specific OSCCs. Any possible direct or indirect role of Betapapillomavirus genus members and TVV in OSCCs remains speculative and requires further investigation.

Human Papillomaviruses and Skin Cancer

Human papillomaviruses (HPVs) infect squamous epithelia and can induce hyperproliferative lesions. More than 220 different HPV types have been characterized and classified into five different genera. While mucosal high-risk HPVs have a well-established causal role in anogenital carcinogenesis, the biology of cutaneous HPVs is less well understood.From patients with the rare genetic disorder epidermodysplasia verruciformis (EV) and animal models, evidence is accumulating that cutaneous PV of genus β synergize with ultraviolet (UV) radiation in the development of cutaneous squamous cell carcinoma (cSCC). In 2009, the International Agency for Research on Cancer (IARC) classified the genus β-HPV types 5 and 8 as "possible carcinogenic" biological agents (group 2B) in EV disease. Epidemiological and biological studies indicate that genus β-PV infection may also play a role in UV-mediated skin carcinogenesis in non-EV patients. However, they rather act at early stages of carcinogenesis and become dispensable for the maintenance of the malignant phenotype, compatible with a "hit-and-run" mechanism.This chapter will give an overview on genus β-PV infections and discuss similarities and differences of cutaneous and genus α mucosal high-risk HPV in epithelial carcinogenesis.

β-HPV 8E6 Attenuates ATM and ATR Signaling in Response to UV Damage

Given the high prevalence of cutaneous genus beta human papillomavirus (β-HPV) infections, it is important to understand how they manipulate their host cells. This is particularly true for cellular responses to UV damage, since our skin is continually exposed to UV. The E6 protein from β-genus HPV (β-HPV E6) decreases the abundance of two essential UV-repair kinases (ATM and ATR). Although β-HPV E6 reduces their availability, the impact on downstream signaling events is unclear. We demonstrate that β-HPV E6 decreases ATM and ATR activation. This inhibition extended to XPA, an ATR target necessary for UV repair, lowering both its phosphorylation and accumulation. β-HPV E6 also hindered POLη accumulation and foci formation, critical steps in translesion synthesis. ATM’s phosphorylation of BRCA1 is also attenuated by β-HPV E6. While there was a striking decrease in phosphorylation of direct ATM/ATR targets, events further down the cascade were not reduced. In summary, despite being incomplete, β-HPV 8E6’s hindrance of ATM/ATR has functional consequences.

Papillomavirus Immune Evasion Strategies Target the Infected Cell and the Local Immune System

Persistent infection with human papillomavirus (HPV) initiates ~5% of all human cancers, and particularly cervical and oropharyngeal cancers. HPV vaccines prevent HPV infection, but do not eliminate existing HPV infections. Papillomaviruses induce hyperproliferation of epithelial cells. In this review we discuss how hyperproliferation renders epithelial cells less sensitive to immune attack, and impacts upon the efficiency of the local immune system. These observations have significance for the design of therapeutic HPV cancer immunotherapies.

The molecular biology and HPV drug responsiveness of cynomolgus macaque papillomaviruses support their use in the development of a relevant in vivo model for antiviral drug testing

Due to the extreme tissue and species restriction of the papillomaviruses (PVs), there is a great need for animal models that accurately mimic PV infection in humans for testing therapeutic strategies against human papillomaviruses (HPVs). In this study, we present data that demonstrate that in terms of gene expression during initial viral DNA amplification, Macaca fascicularis PV (MfPV) types 5 and 8 appear to be similar to mucosal oncogenic HPVs, while MfPV1 (isolated from skin) resembles most high-risk cutaneous beta HPVs (HPV5). Similarities were also observed in replication properties during the initial amplification phase of the MfPV genomes. We demonstrate that high-risk mucosal HPV-specific inhibitors target the transient replication of the MfPV8 genomes, which indicates that similar pathways are used by the high-risk HPVs and MfPVs during their genome replication. Taking all into account, we propose that Macaca fascicularis may serve as a highly relevant model for preclinical tests designed to evaluate therapeutic strategies against HPV-associated lesions.

Beta Human Papillomavirus and Associated Diseases

The cutaneous human papillomavirus (HPV), mostly from β- and γ-HPV genus, is ubiquitously distributed throughout the human body and may be part of the commensal flora. The association of β-HPVs and cutaneous squamous cell carcinoma (cSCC) development was initially reported in patients with the rare genetic disorder Epidermodysplasia verruciformis. Likewise, immunosuppressed organ transplant recipients have an increased susceptibility to β-HPV infections in the skin as well as to cSCC development. Although ultraviolet radiation (UVR) is the main risk factor of cSCC, experimental data points toward β-HPVs as co-carcinogens, which appear to be required solely at early stages of skin carcinogenesis by facilitating the accumulation of UVR-induced DNA mutations. Several epidemiological studies relying on different biomarkers of β-HPV infections have also been conducted in immunocompetent individuals to access their association with cSCC development. Additionally, in vivo and in vitro studies are presenting cumulative evidence that E6 and E7 proteins from specific β-HPVs exhibit transforming activities and may collaborate with different environmental factors in promoting carcinogenesis. Nevertheless, further research is crucial to better understand the pathological implications of the broad distribution of these HPVs.

High prevalence of Gammapapillomaviruses (Gamma-PVs) in pre-malignant cutaneous lesions of immunocompetent individuals using a new broad-spectrum primer system, and identification of HPV210, a novel Gamma-PV type

Genus Gammapapillomavirus (Gamma-PV) is the most diverse and largest clade within the Papillomaviridae family. A novel set of degenerate primers targeting the E1 gene was designed and further used in combination with the well-known CUT PCR assay to assess HPV prevalence and genus distribution in a variety of cutaneous samples from 448 immunocompetent individuals. General HPV, Gamma-PV and mixed infections prevalence were significantly higher in actinic keratosis with respect to benign and malignant neoplasms, respectively (p = 0.0047, p = 0.0172, p = 0.00001). Gamma-PVs were significantly more common in actinic keratosis biopsies than Beta- and Alpha-PVs (p = 0.002). The full-length genome sequence of a novel putative Gamma-PV type was amplified by 'hanging droplet' long-range PCR and cloned. The novel virus, designated HPV210, clustered within species Gamma-12. This study provides an additional tool enabling detection of HPV infections in skin and adds new insights about possible early roles of Gamma-PVs in the development of cutaneous malignant lesions.

Epidemiology and biology of cutaneous human papillomavirus

Cutaneous human papillomaviruses (HPVs) include β- and γ-HPVs, in addition to a small fraction of α-HPVs. β-HPVs were first isolated from patients with the rare genetic disorder Epidermodysplasia verruciformis, and they are associated with the development of nonmelanoma skin cancer at sun-exposed skin sites in these individuals. Organ transplant recipients also have greater susceptibility to β-HPV infection of the skin and an increased risk of developing nonmelanoma skin cancer. In both immunosuppressed and immunocompromised individuals, cutaneous HPVs are ubiquitously disseminated throughout healthy skin and may be an intrinsic part of the commensal flora. Functional analysis of E6 and E7 proteins of specific cutaneous HPVs has provided a mechanistic comprehension of how these viruses may induce carcinogenesis. Nevertheless, additional research is crucial to better understand the pathological implications of the broad distribution of these HPVs.

Generation of a novel next-generation sequencing-based method for the isolation of new human papillomavirus types

With the advent of new molecular tools, the discovery of new papillomaviruses (PVs) has accelerated during the past decade, enabling the expansion of knowledge about the viral populations that inhabit the human body. Human PVs (HPVs) are etiologically linked to benign or malignant lesions of the skin and mucosa. The detection of HPV types can vary widely, depending mainly on the methodology and the quality of the biological sample. Next-generation sequencing is one of the most powerful tools, enabling the discovery of novel viruses in a wide range of biological material. Here, we report a novel protocol for the detection of known and unknown HPV types in human skin and oral gargle samples using improved PCR protocols combined with next-generation sequencing. We identified 105 putative new PV types in addition to 296 known types, thus providing important information about the viral distribution in the oral cavity and skin.

Chronic Inflammatory Microenvironment in Epidermodysplasia Verruciformis Skin Lesions: Role of the Synergism Between HPV8 E2 and C/EBPβ to Induce Pro-Inflammatory S100A8/A9 Proteins

Persistent genus β-HPV (human papillomavirus) infection is a major co-factor for non-melanoma skin cancer in patients suffering from the inherited skin disease epidermodysplasia verruciformis (EV). Malignant EV lesions are particularly associated with HPV type 5 or 8. There is clinical and molecular evidence that HPV8 actively suppresses epithelial immunosurveillance by interfering with the recruitment of Langerhans cells, which may favor viral persistence. Mechanisms how persistent HPV8 infection promotes the carcinogenic process are, however, less well understood. In various tumor types chronic inflammation has a central role in tumor progression. The calprotectin complex consisting of S100A8 and S100A9 proteins has recently been identified as key driver of chronic and tumor promoting inflammation in skin carcinogenesis. It induces chemotaxis of neutrophil granulocytes and modulates inflammatory as well as immune responses. In this study, we demonstrate that skin lesions of EV-patients are massively infiltrated by inflammatory cells, including CD15⁺ granulocytes. At the same time we observed a very strong expression of S100A8 and S100A9 proteins in lesional keratinocytes, which was mostly confined to the suprabasal layers of the epidermis. Both proteins were hardly detected in non-lesional skin. Further experiments revealed that the HPV8 oncoproteins E6 and E7 were not involved in S100A8/A9 up-regulation. They rather suppressed differentiation-induced S100A8/A9 expression. In contrast, the viral transcription factor E2 strongly enhanced PMA-mediated S100A8/A9 up-regulation in primary human keratinocytes. Similarly, a tremendous up-regulation of both S100 proteins was observed, when minute amounts of the PMA-inducible CCAAT/enhancer binding protein β (C/EBPβ), which is expressed at low levels in the suprabasal layers of the epidermis, were co-expressed together with HPV8 E2. This confirmed our previous observation that C/EBPβ interacts and functionally synergizes with the HPV8 E2 protein in differentiation-dependent gene expression. Potent synergistic up-regulation of S100A8/A9 was seen at transcriptional and protein levels. S100A8/A9 containing supernatants from keratinocytes co-expressing HPV8 E2 and C/EBPβ significantly induced chemotaxis of granulocytes in migration assays supporting the relevance of our finding. In conclusion, our data suggest that the HPV8 E2 protein actively contributes to the recruitment of myeloid cells into EV skin lesions, which may support chronic inflammation and progression to skin cancer.

Human papillomavirus-associated cutaneous disease burden in human immunodeficiency virus (HIV)-positive patients: the role of human papillomavirus vaccination and a review of the literature

Human papillomavirus (HPV) infection is related to the development of cutaneous squamous cell carcinoma, oropharyngeal carcinoma, and anogenital malignancies. Patients infected with human immunodeficiency virus (HIV) have impaired cell-mediated immunity, placing them at risk for more prolonged infection with a greater likelihood of disease expression. This presents important implications for screening and treatment of HPV in the HIV patient population. The use of prophylactic vaccines directed against HPV has been a promising clinical development, though the immunogenicity of these vaccines in the immunocompromised host and in patients with previously established HPV infections has not been well established. In this review, we describe the pathogenesis and epidemiology of HPV-related cutaneous malignancies in patients with HIV. We outline the current guidelines and recent advances in the field of HPV vaccination. It is our hope that increasing awareness of the HPV-related HIV comorbidities will lead to developments in preventative medicine capable of reducing the burden of these diseases. We recognize the importance of prevention as a primary defense against disease and hope that this article organizes and disseminates recent findings in the field of HPV-associated comorbidities in the HIV population.

Loss of Genome Fidelity: Beta HPVs and the DNA Damage Response

While the role of genus alpha human papillomaviruses in the tumorigenesis and tumor maintenance of anogenital and oropharyngeal cancers is well-established, the role of genus beta human papilloviruses (β-HPVs) in non-melanoma skin cancers (NMSCs) is less certain. Persistent β-HPV infections cause NMSCs in sun-exposed skin of people with a rare genetic disorder, epidermodysplasia verruciformis. However, β-HPV infections in people without epidermodysplasia verruciformis are typically transient. Further, β-HPV gene expression is not necessary for tumor maintenance in the general population as on average there is fewer than one copy of the β-HPV genome per cell in NMSC tumor biopsies. Cell culture, epidemiological, and mouse model experiments support a role for β-HPV infections in the initiation of NMSCs through a "hit and run" mechanism. The virus is hypothesized to act as a cofactor, augmenting the genome destabilizing effects of UV. Supporting this idea, two β-HPV proteins (β-HPV E6 and E7) disrupt the cellular response to UV exposure and other genome destabilizing events by abrogating DNA repair and deregulating cell cycle progression. The aberrant damage response increases the likelihood of oncogenic mutations capable of driving tumorigenesis independent of a sustained β-HPV infection or continued viral protein expression. This review summarizes what is currently known about the deleterious effects of β-HPV on genome maintenance in the context of the virus's putative role in NMSC initiation.

The PDZ-Binding Motif of HPV16-E6 Oncoprotein Modulates the Keratinization and Stemness Transcriptional Profile In Vivo

Objective

The aim of this work was to compare the early gene expression profiles in the skin of HPV16-E6 transgenic mice regulated by the E6 PDZ-binding motif.

Materials and Methods

The global transcriptional profiles in dorsal skin biopsies from K14E6 and K14E6Δ146-151 transgenic mice were compared using microarrays. Relevant genes obtained from the most differentially expressed processes were further examined by RT-qPCR, in situ RT-PCR, Western blot, or immunofluorescence.

Results

The transcriptomic landscape of K14E6 versus K14E6Δ146-151 shows that the most affected expression profiles were those related to keratinocyte differentiation, stem cell maintenance, and keratinization. Additionally, downregulation of epidermal stemness markers such as K15 and CD34, as well as the upregulation of cytokeratin 6b, appeared to be dependent on the E6 PDZ-binding motif. Finally, wound healing, a physiological process linked to stemness, is impaired in the K14E6 mice compared to K14E6Δ146-151.

Conclusion

The E6 PDZ-binding motif appears to affect stemness and keratinization during early stages of skin carcinogenesis. As E6 plays a significant role in HPV-induced skin carcinogenesis, the K14E6 versus K14E6Δ146-151 transcriptional profile provides a source of valuable data to uncover novel E6 functions in the skin.

Identification of C/EBPα as a novel target of the HPV8 E6 protein regulating miR-203 in human keratinocytes

Patients suffering from Epidermodysplasia verruciformis (EV), a rare inherited skin disease, display a particular susceptibility to persistent infection with cutaneous genus beta-human papillomavirus (beta-HPV), such as HPV type 8. They have a high risk to develop non-melanoma skin cancer at sun-exposed sites. In various models evidence is emerging that cutaneous HPV E6 proteins disturb epidermal homeostasis and support carcinogenesis, however, the underlying mechanisms are not fully understood as yet. In this study we demonstrate that microRNA-203 (miR-203), a key regulator of epidermal proliferation and differentiation, is strongly down-regulated in HPV8-positive EV-lesions. We provide evidence that CCAAT/enhancer-binding protein α (C/EBPα), a differentiation-regulating transcription factor and suppressor of UV-induced skin carcinogenesis, directly binds the miR-203 gene within its hairpin region and thereby induces miR-203 transcription. Our data further demonstrate that the HPV8 E6 protein significantly suppresses this novel C/EBPα/mir-203-pathway. As a consequence, the miR-203 target ΔNp63α, a proliferation-inducing transcription factor, is up-regulated, while the differentiation factor involucrin is suppressed. HPV8 E6 specifically down-regulates C/EBPα but not C/EBPβ expression at the transcriptional level. As shown in knock-down experiments, C/EBPα is regulated by the acetyltransferase p300, a well-described target of cutaneous E6 proteins. Notably, p300 bound significantly less to the C/EBPα regulatory region in HPV8 E6 expressing keratinocytes than in control cells as demonstrated by chromatin immunoprecipitation. In situ analysis confirmed congruent suprabasal expression patterns of C/EBPα and miR-203 in non-lesional skin of EV-patients. In HPV8-positive EV-lesions both factors are potently down-regulated in vivo further supporting our in vitro data. In conclusion our study has unraveled a novel p300/C/EBPα/mir-203-dependent mechanism, by which the cutaneous HPV8 E6 protein may expand p63-positive cells in the epidermis of EV-patients and disturbs fundamental keratinocyte functions. This may drive HPV-mediated pathogenesis and may potentially also pave the way for skin carcinogenesis in EV-patients.

Cutaneous genus beta-HPV types infect skin keratinocytes. Their potential role in skin carcinogenesis, particularly in immunosuppressed patients, has become a major field of interest. Patients suffering from the rare genetic disorder Epidermodysplasia verruciformis (EV) are highly susceptible to persistent genus beta-HPV infection and have an increased risk to develop non-melanoma skin cancer at sun-exposed sites. Thus, EV serves as a valuable model disease for studying genus beta-HPV biology. Here, we demonstrate that in human HPV8-infected EV skin lesions, the ‘stemness-repressing’ microRNA-203 is strongly down-regulated. In contrast, cells expressing the miR-203-regulated ‘stemness-maintaining’ factor p63, are highly amplified. Notably, we identified the transcription factor C/EBPα, a well-known suppressor of UV-induced skin carcinogenesis, as a p300-dependent target of the HPV8-encoded E6 oncoprotein and as a critical inducer of miR-203 gene expression. Our data provide evidence for a novel p300/C/EBPα/miR-203-dependent pathway, which links HPV8 infection to the expansion of p63-positive cells in the epidermis of EV-patients. This may contribute to the beta-HPV-induced disturbance of epidermal homeostasis and pave the way for skin carcinogenesis.

Natural history of human papillomavirus infection of sun-exposed healthy skin of immunocompetent individuals over three climatic seasons and identification of HPV209, a novel betapapillomavirus

We present the first longitudinal study reporting the natural history of human papillomavirus (HPV) infection in sun-exposed skin of healthy individuals living in a geographical area in which solar UV radiation is influenced by the ozone content of the atmosphere. During three climatic seasons, skin swab samples were obtained from 78 healthy individuals and the prevalence of cutaneous HPVs was assessed with broad-spectrum FAP and CUT primers and determined at 54, 45 and 47 % in spring, summer and winter, respectively. Frequencies of mixed HPV infections were significantly higher in spring with respect to summer and winter (P=0.02). Seventy-one different HPV types/putative types were identified. While 62 volunteers were HPV-infected in at least one season, 23 had persistent infections. β-PVs (β-1) were the most prevalent and persistent. Age was associated with both the infection status (P=0.01) and the type of HPV infection (no infection, indeterminate/transient, persistent P=0.02). The molecular/phylogenetic analysis of the newly identified β-PV, officially designated as HPV209, showed that the virus has a typical genomic organization of cutaneous HPVs with five early (E6, E7, E1, E2 and E4) and two late genes (L2 and L1), which clusters to the species β-2. This provides useful data on cutaneous HPV infections in high UV-exposed regions.

Cutaneous squamous cell carcinoma: an epidemiological review

Cutaneous squamous cell carcinoma (SCC) is a common cancer in white populations and its disease burden is often substantially underestimated. SCC occurs more often in men than women and increases dramatically with age; those affected often develop multiple primaries over time, which increases the burden. The main external cause is solar ultraviolet radiation (UVR), with immunosuppression being the other established risk factor, shown by the high SCC rates in organ transplant recipients. Sunbed use and certain genetic disorders and medical conditions are also associated with SCC, while associations with human papillomavirus infection and high bodyweight are not established. The presence of actinic keratoses (AKs) on sun-damaged skin is one of the strongest predictors of SCC in unaffected people and a very small proportion of AKs are SCC precursors, although the true rate of malignant transformation of AKs is unknown. The mainstay of SCC prevention is protection of the skin from undue sun exposure by use of clothing cover and sunscreen during summer or in sunny places. Educational, behavioural and multicomponent interventions directed at individuals ranging from parents of newborns, to school children and adolescents, to outdoor workers, have repeatedly been shown to be effective in improving sun-protective behaviours. Health policies can facilitate SCC prevention by setting standards for relevant behaviours to reduce UVR exposure, for example, by legislated restriction of the tanning industry. Skin cancer prevention initiatives are generally highly cost-effective and public investment should be encouraged to control the growing public health problems caused by SCC.

Cutaneous squamous cell cancer (cSCC) risk and the human leukocyte antigen (HLA) system

Cutaneous squamous cell carcinoma (cSCC) is the second most common cancer among Caucasians in the United States, with rising incidence over the past decade. Treatment for non-melanoma skin cancer, including cSCC, in the United States was estimated to cost $4.8 billion in 2014. Thus, an understanding of cSCC pathogenesis could have important public health implications. Immune function impacts cSCC risk, given that cSCC incidence rates are substantially higher in patients with compromised immune systems. We report a systematic review of published associations between cSCC risk and the human leukocyte antigen (HLA) system. This review includes studies that analyze germline class I and class II HLA allelic variation as well as HLA cell-surface protein expression levels associated with cSCC risk. We propose biological mechanisms for these HLA-cSCC associations based on known mechanisms of HLA involvement in other diseases. The review suggests that immunity regulates the development of cSCC and that HLA-cSCC associations differ between immunocompetent and immunosuppressed patients. This difference may reflect the presence of viral co-factors that affect tumorigenesis in immunosuppressed patients. Finally, we highlight limitations in the literature on HLA-cSCC associations, and suggest directions for future research aimed at understanding, preventing and treating cSCC.

Chimeric L2-Based Virus-Like Particle (VLP) Vaccines Targeting Cutaneous Human Papillomaviruses (HPV)

Common cutaneous human papillomavirus (HPV) types induce skin warts, whereas species beta HPV are implicated, together with UV-radiation, in the development of non-melanoma skin cancer (NMSC) in immunosuppressed patients. Licensed HPV vaccines contain virus-like particles (VLP) self-assembled from L1 major capsid proteins that provide type-restricted protection against mucosal HPV infections causing cervical and other ano-genital and oro-pharyngeal carcinomas and warts (condylomas), but do not target heterologous HPV. Experimental papillomavirus vaccines have been designed based on L2 minor capsid proteins that contain type-common neutralization epitopes, to broaden protection to heterologous mucosal and cutaneous HPV types. Repetitive display of the HPV16 L2 cross-neutralization epitope RG1 (amino acids (aa) 17-36) on the surface of HPV16 L1 VLP has greatly enhanced immunogenicity of the L2 peptide. To more directly target cutaneous HPV, L1 fusion proteins were designed that incorporate the RG1 homolog of beta HPV17, the beta HPV5 L2 peptide aa53-72, or the common cutaneous HPV4 RG1 homolog, inserted into DE surface loops of HPV1, 5, 16 or 18 L1 VLP scaffolds. Baculovirus expressed chimeric proteins self-assembled into VLP and VLP-raised NZW rabbit immune sera were evaluated by ELISA and L1- and L2-based pseudovirion (PsV) neutralizing assays, including 12 novel beta PsV types. Chimeric VLP displaying the HPV17 RG1 epitope, but not the HPV5L2 aa53-72 epitope, induced cross-neutralizing humoral immune responses to beta HPV. In vivo cross-protection was evaluated by passive serum transfer in a murine PsV challenge model. Immune sera to HPV16L1-17RG1 VLP (cross-) protected against beta HPV5/20/24/38/96/16 (but not type 76), while antisera to HPV5L1-17RG1 VLP cross-protected against HPV20/24/96 only, and sera to HPV1L1-4RG1 VLP cross-protected against HPV4 challenge. In conclusion, RG1-based VLP are promising next generation vaccine candidates to target cutaneous HPV infections.

Proteomic analysis of the gamma human papillomavirus type 197 E6 and E7 associated cellular proteins

Gamma HPV197 was the most frequently identified HPV when human skin cancer specimens were analyzed by deep sequencing (Arroyo Muhr et al., Int. J. Cancer 136: 2546-55, 2015). To gain insight into the biological activities of HPV197, we investigated the cellular interactomes of HPV197 E6 and E7. HPV197 E6 protein interacts with a broad spectrum of cellular LXXLL domain proteins, including UBE3A and MAML1. HPV197 E6 also binds and inhibits the TP53 tumor suppressor and interacts with the CCR4-NOT ubiquitin ligase and deadenylation complex. Despite lacking a canonical retinoblastoma (RB1) tumor suppressor binding site, HPV197 E7 binds RB1 and activates E2F transcription. Hence, HPV197 E6 and E7 proteins interact with a similar set of cellular proteins as E6 and E7 proteins encoded by HPVs that have been linked to human carcinogenesis and/or have transforming activities in vitro.

Cutaneous human papillomavirus genotypes in different kinds of skin lesions in Argentina

Cutaneous human papillomaviruses (HPVs) comprise a large and highly heterogeneous virus group. Some of the cutaneous HPVs of the genus Beta have been suggested as a co-factor in the development of non-melanoma skin cancer (NMSC). The aim of this study was to determine cutaneous HPV prevalence and type-specific distribution in different kinds of skin lesions from Argentine patients visiting Dermatology Departments of three hospitals from Buenos Aires. A cross-sectional analysis was performed. HPV DNA was analyzed in (i) 3 patients with Epidermodysplasia verruciformis (EV) harboring benign lesions (BL) (n = 1) and squamous cell carcinoma (SCC) (n = 4); (ii) 240 non-EV patients harboring: (a) BL (n = 38), (b) Actinic Keratosis (AK) (n = 83), (c) SCC (n = 74), and (d) basal cell carcinoma (BCC) (n = 96). Detection and genotyping of 35 cutaneous HPV DNA was carried out by BGC-PCR and GP5+/6 + PCR followed by reverse line blot assay. In EV patients, Beta types were found in all lesions (5/5), including the potentially high-risk HPV types 5 and 8, mostly in multiple infections. In non-EV patients, cutaneous types were found in 50.0% of BL, 43.4% of AK, 31.1% of SCC, and 16.7% of BCC. Beta HPVs were the most frequently found in all lesions, being present in all AK and SCC cases that were positive for HPV. No type-specific correlation with lesion severity was found. In our series, a wide spectrum of cutaneous HPV types was detected in different skin lesions. A possible role for these HPVs in skin carcinogenesis deserves further study. J. Med. Virol. 89:352-357, 2017. © 2016 Wiley Periodicals, Inc.

Human papillomavirus molecular biology

Human papillomaviruses are small DNA viruses with a tropism for squamous epithelia. A unique aspect of human papillomavirus molecular biology involves dependence on the differentiation status of the host epithelial cell to complete the viral lifecycle. A small group of these viruses are the etiologic agents of several types of human cancers, including oral and anogenital tract carcinomas. This review focuses on the basic molecular biology of human papillomaviruses.

The Human Papillomavirus and Its Role in Plantar Warts: A Comprehensive Review of Diagnosis and Management

Viral warts or verruca pedis (plantar warts) are common skin conditions seen in both children and adults. Human papilloma virus (HPV), a DNA virus, is responsible for plantar verrucae. It needs an epidermal abrasion and a transiently impaired immune system to inoculate a keratinocyte. These entities are a therapeutic conundrum for many practitioners. This article discusses HPV infiltration and its subtypes involved in plantar warts; the evaluation of patients with plantar warts; and subsequent treatment options, such as laser, Candida albicans immunotherapy, topical therapy such as phytotherapy, and surgical excision.

Prevalence and Associated Risk Factors of Human Papillomavirus in Healthy Skin Specimens Collected from Rural Anyang, China, 2006-2008

Skin infections with cutaneous human papillomavirus (HPV) have been linked to the development of non-melanoma skin cancer, in which mucosal HPV may also play a crucial role. However, systematic investigations of the distribution and associated factors of HPV infection in healthy skin of the general population are scarce. HPV DNA from palmar exfoliated cells of 2,087 individuals was detected by FAP6085/64 and SPF1/GP6+ primers followed by sequencing. A total of 338 papillomavirus types were detected, with HPV-3, HPV-57, and HPV-49 being the most dominant types. The overall prevalence for HPV DNA on skin was 79.92% and for alpha-, beta-, and gamma-HPV were 27.07%, 38.76%, and 29.56%, respectively. Having multiple lifetime sexual partners (adjusted odds ratio 1.60), being a migrant worker (adjusted odds ratio 2.05, reference: farmers), and frequent bathing (Ptrend = 0.001) were associated with alpha-HPV DNA presence. Advancing age increased the detection risk of beta-HPV (Ptrend = 0.001). Higher education (Ptrend = 0.017) and frequent bathing (Ptrend = 0.001) were positively related to gamma-HPV positivity. This study demonstrates that alpha-HPV commonly exists on healthy skin of the general population in rural China, and alpha- and gamma-HPV infections are related to certain behaviors, different from beta-HPV infection. These findings are crucial to better understanding the biology of HPV infection and may be suggestive of the potential transmission of these viruses.

HPV vaccination for prevention of skin cancer

Cutaneous papillomaviruses are associated with specific skin diseases, such as extensive wart formation and the development of non-melanoma skin cancer (NMSC), especially in immunosuppressed patients. Hence, clinical approaches are required that prevent such lesions. Licensed human papillomavirus (HPV) vaccines confer type-restricted protection against HPV types 6, 11, 16 and 18, responsible of 90% of genital warts and 70% of cervical cancers, respectively. However, they do not protect against less prevalent high-risk types or cutaneous HPVs. Over the past few years, several studies explored the potential of developing vaccines targeting cutaneous papillomaviruses. These vaccines showed to be immunogenic and prevent skin tumor formation in certain animal models. Furthermore, under conditions mimicking the ones found in the intended target population (i.e., immunosuppression and in the presence of an already established infection before vaccination), recent preclinical data shows that immunization can still be effective. Strategies are currently focused on finding vaccine formulations that can confer protection against a broad range of papillomavirus-associated diseases. The state-of-the-art of these approaches and the future directions in the field will be presented.

Nrf2 Activation Promotes Keratinocyte Survival during Early Skin Carcinogenesis via Metabolic Alterations

Pharmacologic activation of the transcription factor NRF2 has been suggested to offer a strategy for cancer prevention. In this study, we present evidence from murine tumorigenesis experiments suggesting there may be limitations to this possibility, based on tumorigenic effects of Nrf2 in murine keratinocytes that have not been described previously. In this setting, Nrf2 expression conferred metabolic alterations in keratinocytes that were protumorigenic in nature, affecting enzymes involved in glutathione biosynthesis or in the oxidative pentose phosphate pathway and other NADPH-producing enzymes. Under stress conditions, coordinate increases in NADPH, purine, and glutathione levels promoted the survival of keratinocytes harboring oncogenic mutations, thereby promoting tumor development. The protumorigenic activity of Nrf2 in keratinocytes was particularly significant in a mouse model of skin tumorigenesis that did not rely upon chemical carcinogenesis. In exploring the clinical relevance of our findings, we confirm that NRF2 and protumorigenic NRF2 target genes were activated in some actinic keratoses, the major precancerous lesion in human skin. Overall, our results reveal an unexpected tumor-promoting activity of activated NRF2 during early phases of skin tumorigenesis.

Association between betapapillomavirus seropositivity and keratinocyte carcinoma-prospects for prophylactic vaccination?

In this issue, Genders et al. (2015) demonstrate in a cohort of organ transplant recipients that betapapillomavirus seropositivity around transplantation significantly increases the risk of developing keratinocyte carcinomas. These results further substantiate an etiologic role of betapapillomaviruses in skin cancer and raise prospects of anti-viral immunotherapy.

A systematic investigation of the contribution of genetic variation within the MHC region to HPV seropositivity

High-risk mucosal types of human papillomavirus (HPV) cause anogenital and oropharyngeal cancers, whereas cutaneous types (e.g. HPV8 and 77) are suspected to be involved in non-melanoma skin cancer. The antibody response to HPVs is a key determinant of protective immunity, but not all infected individuals seroconvert. Genetic variability of the host may have large impact on seroconversion. A previous genome-wide association study (GWAS) has identified a susceptibility locus (rs41270488) for HPV8 seropositivity within the major histocompatibility complex (MHC) region. To further study this locus, we imputed alleles at classical leukocyte antigen (HLA) loci using HLA*IMP:02 with a reference panel from the HapMap Project and the 1958 Birth Cohort, and conducted an integrated analysis among 4811 central European subjects to assess the contribution of classical HLA alleles and gene copy number variation (CNV) at the hypervariable DRB locus within the MHC region to HPV seropositivity at both the individual HPV type level and the phylogenetic species level. Our study provides evidence that the association noted between rs41270488 and HPV8 seropositivity is driven by two independent variants, namely DQB1*0301 [odds ratio (OR) = 1.51, 95% confidence interval (CI) = 1.36-1.68, P = 1.0 × 10(-14)] and DRB1*1101 (OR = 1.89, 95%CI = 1.57-2.28, P = 1.5 × 10(-11)) within the HLA class II region. Additionally, we identified two correlated alleles DRB1*0701 (OR = 1.67, 95%CI = 1.41-1.98, P = 2.6 × 10(-9)) and DQA1*0201 (OR = 1.67, 95%CI = 1.38-1.93, P = 1.7 × 10(-8)), to be associated with HPV77 seropositivity. Comparable results were observed through imputation using SNP2HLA with another reference panel from the Type 1 diabetes Genetics Consortium. This study provides support for an important role of HLA class II alleles in antibody response to HPV infection.

Role of human papillomaviruses in carcinogenesis

The human papillomavirus (HPV) family comprises more than 170 different types that preferentially infect the mucosa of the genitals, upper-respiratory tract, or the skin. The 'high-risk HPV type', a sub-group of mucosal HPVs, is the cause of approximately 5% of all human cancers, which corresponds to one-third of all virus-induced tumours. Within the high-risk group, HPV16 is the most oncogenic type, being responsible for approximatively 50% of all worldwide cervical cancers. Many studies suggest that, in addition to the high-risk mucosal HPV types, certain cutaneous HPVs also have a role in the development of non-melanoma skin cancer (NMSC). Functional studies on the HPV early gene products showed that E6 and E7 play a key role in carcinogenesis. These two proteins use multiple mechanisms to evade host immune surveillance, allowing viral persistence, and to deregulate cell cycle and apoptosis control, thus facilitating the accumulation of DNA damage and ultimately cellular transformation. The demonstration that high-risk HPV types are the etiological agents of cervical cancer allowed the implementation in the clinical routine of novel screening strategies for cervical lesions, as well as the development of a very efficient prophylactic vaccine. Because of these remarkable achievements, there is no doubt that in the coming decades we will witness a dramatic reduction of cervical cancer incidence worldwide.

HPV Carcinomas in Immunocompromised Patients

Human papillomavirus (HPV) infection is the most common sexually transmitted disease worldwide and can result in pre-malignancies or overt malignancies of the skin and mucosal surfaces. HPV-related illnesses are an important personal and public health problem causing physical, mental, sexual and financial detriments. Moreover, this set of malignancies severely affects the immunosuppressed population, particularly HIV-positive patients and organ-transplant recipients. There is growing incidence of HPV-associated anogenital malignancies as well as a decrease in the average age of affected patients, likely related to the rising number of high-risk individuals. Squamous cell carcinoma is the most common type of HPV-related malignancy. Current treatment options for HPV infection and subsequent disease manifestations include imiquimod, retinoids, intralesional bleomycin, and cidofovir; however, primary prevention with HPV vaccination remains the most effective strategy. This review will discuss anogenital lesions in immunocompromised patients, cutaneous warts at nongenital sites, the association of HPV with skin cancer in immunocompromised patients, warts and carcinomas in organ-transplant patients, HIV-positive patients with HPV infections, and the management of cutaneous disease in the immunocompromised patient.

Squamous cell cancer--31-year epidemiological study in a city of south Brazil

BACKGROUND

The incidence and morbidity of squamous cell cancers are increasing worldwide. Epidemiological studies with morbidity coefficients about this type of cancer are scarce in Brazil.

OBJECTIVES

To determine morbidity coefficients, analyze and classify the squamous cell cancers diagnosed in the city of Blumenau - SC from 1980 to 2011, according to clinical and histological features.

METHODS

The authors revised 4000 histopathological exams with respect to sex, age, anatomic site and histological type. The morbidity coefficients were calculated using the number of squamous cell cancers found and the annual population estimated by the Brazilian Institute of Geography and Statistics between 1980 and 2011.

RESULTS

A total of 4000 tumors were identified, 2249 (56.2%) in male and 1751 (43.8%) in female patients. The standard incidence rates varied from 40 cases in 1980 to 120 cases/100,000 inhabitants in 2011. The morbidity above 70 years of age reached 1484 cases/100,000 inhabitants in male and 975 in female patients. As to primary anatomic site, we found more tumors on the lips and ears in male and on the face and legs in female patients. As to the degree of involvement, the more frequent were Well Differentiated Squamous cell carcinomas (70%) and Moderate Squamous cell carcinomas (19,1%). The Low Differentiated Squamous cell carcinomas, which represented those with the worst prognosis, were found in 4.5% of the tumors.

CONCLUSION

Squamous cell cancers in Blumenau - SC have similar patterns of distribution regarding age, primary anatomic site and histological types as found in the international literature. The morbidity increased by 300% in the last 31 years, which indicates that we need to dedicate special attention to the older population.