Prevalence and Correlates of β- and γ-Human Papillomavirus Detection in Oral Samples From Mid-Adult Women

HPV Infections-Classification, Pathogenesis, and Potential New Therapies

To date, more than 400 types of human papillomavirus (HPV) have been identified. Despite the creation of effective prophylactic vaccines against the most common genital HPVs, the viruses remain among the most prevalent pathogens found in humans. According to WHO data, they are the cause of 5% of all cancers. Even more frequent are persistent and recurrent benign lesions such as genital and common warts. HPVs are resistant to many disinfectants and relatively unsusceptible to external conditions. There is still no drug available to inhibit viral replication, and treatment is based on removing lesions or stimulating the host immune system. This paper presents the systematics of HPV and the differences in HPV structure between different genetic types, lineages, and sublineages, based on the literature and GenBank data. We also present the pathogenesis of diseases caused by HPV, with a special focus on the role played by E6, E7, and other viral proteins in the development of benign and cancerous lesions. We discuss further prospects for the treatment of HPV infections, including, among others, substances that block the entry of HPV into cells, inhibitors of viral early proteins, and some substances of plant origin that inhibit viral replication, as well as new possibilities for therapeutic vaccines.

Prevalence of Alpha, Beta, and Gamma Human Papillomaviruses in Patients With Head and Neck Cancer and Noncancer Controls and Relation to Behavioral Factors

BACKGROUND

Human papillomaviruses (HPVs) cause head and neck cancer (HNC), which is increasing in incidence in developed countries. We investigated the prevalence of alpha (α), beta (β), and gamma (γ) HPVs among HNC cases and controls, and their relationship with sociodemographic, behavioral, and oral health factors.

METHODS

We obtained oral rinse and brush samples from incident HNC cases (n = 369) and hospital-based controls (n = 439) and tumor samples for a subsample of cases (n = 121). We genotyped samples using polymerase chain reaction with PGMY09-PGMY11 primers and linear array for α-HPV and type-specific multiplex genotyping assay for β-HPV and γ-HPV. Sociodemographic and behavioral data were obtained from interviews.

RESULTS

The prevalence of α-, β-, and γ-HPV among controls was 14%, 56%, and 24%, respectively, whereas prevalence among cases was 42%, 50%, and 33%, respectively. Prevalence of α- and γ-HPV, but not β-HPV, increased with increase in sexual activity, smoking, and drinking habits. No HPV genus was associated with oral health. Tumor samples included HPV genotypes exclusively from the α-genus, mostly HPV-16, in 80% of cases.

CONCLUSIONS

The distribution of α- and γ-HPV, but not β-HPV, seems to vary based on sociodemographic and behavioral characteristics. We did not observe the presence of cutaneous HPV in tumor tissues.

Betapapillomavirus natural history and co-detection with alphapapillomavirus in cervical samples of adult women

Human papillomaviruses (HPV) of the genus Betapapillomavirus can infect both cutaneous and mucosal sites, but research on their natural history at mucosal sites remains scarce. We examined the risk factors and co-detection patterns of HPVs of the Betapapillomavirus and Alphapapillomavirus genera in cervical samples of the Ludwig-McGill cohort study. We assessed a subset of 505 women from the Ludwig-McGill cohort study from São Paulo, Brazil. Cervical samples over the first year of follow-up were tested for DNA of over 40 alphapapillomavirus types and 43 betapapillomavirus types using a type-specific multiplex genotyping polymerase chain reaction assay. We assessed the risk factors for prevalent and incident betapapillomavirus type detection, and whether types were detected more frequently together than expected assuming independence using permutation tests, logistic regression, and Cox regression. We observed significant within-genus clustering but not cross-genus clustering. Multiple betapapillomavirus types were co-detected in the same sample 2.24 (95% confidence interval [CI]: 1.65-3.29) times more frequently than expected. Conversely, co-detections of alphapapillomavirus and betapapillomavirus types in the same sample occurred only 0.64 (95% CI: 0.51-0.83) times as often as expected under independence. In prospective analyses, positivity to one HPV genus was associated with a nonsignificant lower incidence of detection of types in the other genus. Lifetime number of sex partners and new sex partner acquisition were associated with lower risks of prevalent and incident betapapillomavirus detection. Betapapillomaviruses are commonly found in the cervicovaginal tract. Results suggest potentially different mechanisms of transmission for betapapillomavirus genital infections other than vaginal sex.

Prevalence of novel gamma HPV types 223 and 225 in oral cavity and skin of Indian normal and neoplastic participants

Gamma-papillomaviruses, though traditionally classified as cutaneotropic, actual tissue tropism is largely unexplored. This study aimed to evaluate the tissue-specific prevalence of two novel-HPV 223 and 225 in samples of oral mucosa and keratinized epithelium of varied skin parts from 226 female and male subjects, with or without neoplastic/dysplastic lesions in oral cavity or cervix. The gamma-human papillomavirus (gamma-HPV) 223 and 225 DNA presences were determined by polymerase chain reaction (PCR) ursing the HPV type-specific primers and confirmed by Sanger sequencing. Viral load in the HPV 223 and HPV 225 positive samples were determined by absolute real-time quantification method. Alpha-HPV DNA prevalence was also checked in oral mucosa to ascertain coinfection status. Novel HPV 223 was present in 4.4% (10/226) oral mucosal samples of the study population; interestingly all were females with no prevalence in their corresponding skin swab samples. Whereas, the prevalence of HPV 225 was found both in the skin and oral mucosa of 28.2% (N = 37/131) female and 17.9% (N = 17/95) male participants. Alongside, HPV 223 viral load was found to be significantly higher (p = 0.02 < 0.05) in the oral mucosa of diseased participants, whereas, HPV 225 viral load was higher in the oral mucosa of normal participants. Our results suggest that gamma-HPV 223 has its prevalence only in the oral mucosal epithelium, whereas, HPV 225 has its prevalence on both mucosal and keratinized skin epithelium, indicating its dual tropism nature.

Transmission and clearance of human papillomavirus infection in the oral cavity and its role in oropharyngeal carcinoma - A review

The majority of sexually active individuals becomes infected with human papillomavirus (HPV) at least once in their lifetime. Pathways for HPV transmission vary across different mucosal sites per individual. They include autoinoculation within one host, direct transmission between individuals (including perinatal transmission and transmission during sexual activity), and indirect transmission through contact with hands. The authors aim to clarify the prevalence and route of transmission per anatomic site, inter- and intra-individually, using a narrative review of the literature. In conclusion, transmission of HPV to the oral cavity and oropharynx is hypothesised to occur mainly through sexual contact. Transmission of particles through saliva has not been proven and daily living activities are not a documented source of HPV infection. Oropharyngeal HPV related cancer survivors and their partners do not show increased risk of infection during sexual intercourse. Transmission of HPV to the oral cavity (autoinoculation with fingers or transmission through saliva in deep kissing) is probably of limited importance.

Interaction of HPV16 and Cutaneous HPV in Head and Neck Cancer

Simple Summary

Infection with human papillomaviruses (HPV) increases the risk of developing head and neck cancer (HNC). There are over 200 known genotypes of HPV, but only a minority are carcinogenic. Cutaneous genotypes, which are traditionally isolated from the skin, were thought to be benign. However, recent evidence shows that they could be related to some cancers including HNC. Our goal in this study has been to investigate if there is an interaction between HPV16, a high-risk genotype from the alpha genus, with cutaneous HPV (beta and gamma genera) in HNC. We found preliminary evidence that among those infected with HPV16, co-infection with beta HPV could weaken the carcinogenic effect whereas coinfection with gamma HPV could strengthen the carcinogenic effect. While our findings show there might be an interaction between HPV16 and cutaneous HPV, these results are not conclusive and warrant further investigation. Future studies with larger sample sizes are needed.

Abstract

Objectives: Human papillomavirus 16 (HPV16) is an established risk factor for Head and Neck Cancer (HNC). Recent reports have shown that genotypes from the beta (β) and gamma (γ) genera, also known as cutaneous HPV, can be found in the oral cavity, but their role is largely unidentified. We investigated the interaction between oral HPV16 and cutaneous HPV in HNC. Methods: We use data on incident HNC cases (n = 384) and frequency-matched hospital-based controls (n = 423) from the HeNCe Life study in Montreal, Canada. Participants were tested for alpha HPV and cutaneous genera using oral mouth rinse and brush samples. We used unconditional logistic regression to obtain adjusted odds ratios (aOR) and 95% confidence interval (CI) as a measure of the effect between HPV and HNC and assessed the interaction between HPV genotypes on the multiplicative and additive scales. Results: Prevalence of HPV infection was higher among cases (73%) than controls (63.4%), with cases more likely to be coinfected with more than a single genotype, 52.9% vs. 43.5%, respectively. Infection with HPV16 alone had a strong effect on HNC risk aOR = 18.2 [6.2, 53.2], while infection with any cutaneous HPV, but not HPV16, appeared to have the opposite effect aOR = 0.8 [0.6, 1.1]. The observed effect of joint exposure to HPV16 and any cutaneous HPV (aOR = 20.4 [8.3, 50.1]) was stronger than the expected effect based on an assumption of independent exposures but was measured with considerable imprecision. While the point estimate suggests a positive interaction between HPV16 and cutaneous HPV, results were imprecise with relative excess risk due to interaction (RERI) = 2.4 [−23.3, 28.2]. Conclusion: There could be biologic interaction between HPV16 and genotypes from cutaneous genera, which warrants further investigation. Although cutaneous HPVs are not usually found in tumor tissues, they are cofactors that could interact with HPV16 in the oral cavity and thus strengthen the latter’s carcinogenic effect.

Beta HPV Deregulates Double-Strand Break Repair

Beta human papillomavirus (beta HPV) infections are common in adults. Certain types of beta HPVs are associated with nonmelanoma skin cancer (NMSC) in immunocompromised individuals. However, whether beta HPV infections promote NMSC in the immunocompetent population is unclear. They have been hypothesized to increase genomic instability stemming from ultraviolet light exposure by disrupting DNA damage responses. Implicit in this hypothesis is that the virus encodes one or more proteins that impair DNA repair signaling. Fluorescence-based reporters, next-generation sequencing, and animal models have been used to test this primarily in cells expressing beta HPV E6/E7. Of the two, beta HPV E6 appears to have the greatest ability to increase UV mutagenesis, by attenuating two major double-strand break (DSB) repair pathways, homologous recombination, and non-homologous end-joining. Here, we review this dysregulation of DSB repair and emerging approaches that can be used to further these efforts.

Human Papillomavirus Oral Infection: Review of Methodological Aspects and Epidemiology

Oral infection by Human Papillomavirus (HPV) has recently gained great attention because of its involvement in the development of a subset of head and neck squamous cell carcinoma. The role of specific Alpha-HPVs in this regard has been well established, whereas the contribution of other genera is under investigation. Despite their traditional classification as “cutaneous” types, Beta and Gamma HPVs are frequently detected in oral samples. Due to the lack of a standardized protocol, a large variety of methodologies have been used for oral sample collection, DNA extraction, HPV detection and genotyping. Laboratory procedures influence the evaluation of oral HPV prevalence, which largely varies also according to the population characteristics, e.g., age, gender, sexual behavior, Human Immunodeficiency Virus (HIV) status. Nevertheless, oral infection by Beta and Gamma HPVs seems to be even more common than Alpha-HPVs. The latter is 5–7% in the general population, and increases up to 30% approximately in HIV-infected men who have sex with men. Despite major advances in the evaluation of oral HPV prevalence, its natural history is still little understood, especially for Beta and Gamma HPVs. The latest technologies, such as Next Generation Sequencing (NGS), can be exploited to gain new insights into oral HPV, and to improve the identification of novel HPV types.

Predictors of Oral Infection by Mucosal and Cutaneous Human Papillomaviruses in HIV-Infected and Uninfected Men Who Have Sex with Men of the OHMAR Study

Mucosal Human Papillomaviruses (HPVs) play a role in the development of a subset of head and neck cancers. Cutaneous HPVs are abundantly present in the oral cavity. The determinants of these infections have not been extensively investigated. We assessed the correlates of oral infection by alpha and beta and/or gamma HPVs in HIV-infected and uninfected men who have sex with men (MSM). Oral rinse-and-gargles were collected with a mouthwash. Alpha and beta/gamma HPVs were detected using the Linear Array HPV genotyping test and a multiplex PCR combined with Luminex technology, respectively. Multiple logistic regression was performed to identify independent predictors of oral HPV infection. Overall, 193 HIV-uninfected and 117 HIV-infected MSM were enrolled. Among HIV-infected MSM, the only determinant of alpha HPV infection was the number of lifetime oral sex partners (AOR: 8.26, 95% CI: 2.26-30.16). The strongest determinant of beta/gamma HPV infection was represented by practicing condomless receptive oral sex (AOR: 10.76, 95% CI: 1.56-74.17). Age was independently associated with alpha HPV infection in HIV-uninfected MSM. Beta/gamma HPV infection was not associated with sexual behavior in these subjects. In conclusion, predictors of oral infection differ between HIV-infected and uninfected MSM, as well as between alpha and beta/gamma HPVs.

Diversity of human papillomavirus in the anal canal of HIV-positive and HIV-negative men

BACKGROUND

To characterize the HPV diversity in the anal mucosa of men with different sexual behavior and HIV status by next-generation sequencing (NGS).

METHODS

Anal swabs from HIV-positive (n = 94; mean age, 38 years) and HIV-negative (n = 100; mean age, 37.5 years) men who have sex with men (MSM) and HIV-negative men (predominantly men who have sex with women, MSW) (n = 99; mean age, 38.2 years) were analyzed by broad-spectrum PCR protocols combined with NGS.

FINDINGS

Alpha HPV types (n = 74) were detected mainly in the MSM groups (HPV6, 11, and 43 were the most abundant types) compared with MSW (n = 16) (HPV11, 32, and 87 were among the most abundant). In contrast, beta HPVs were more abundantly detected among MSW (n = 45) than in the HIV-positive (n = 16) and HIV-negative (n = 26) MSM groups. Gamma HPVs were detected almost equally in HIV-positive MSM (n = 62), HIV-negative MSM (n = 58), and MSW (n = 57). In addition, 31 putative novel PV types were identified.

CONCLUSIONS

Our data show that beta and gamma HPV types are present in the anal mucosa, thus reinforcing the existing evidence that they can be detected at anatomical sites other than skin. Alpha and beta HPV distribution among these three groups appears to vary according to sexual behavior.

Oral Infection by Mucosal and Cutaneous Human Papillomaviruses in the Men Who Have Sex with Men from the OHMAR Study

Both mucosal and cutaneous Human Papillomaviruses (HPVs) can be detected in the oral cavity, but investigations regarding the epidemiology of cutaneous HPVs at this site are scarce. We assessed mucosal (alpha) and cutaneous (beta and gamma) HPV infection in oral samples of HIV-infected and uninfected men who have sex with men (MSM). Oral rinse-and-gargles were collected from 310 MSM. Alpha HPVs were detected using the Linear Array, whereas beta and gamma HPVs were detected using multiplex PCR and Luminex technology. An amplicon-based next-generation sequencing (NGS) protocol was applied to a subset of samples collected from 30 HIV-uninfected and 30 HIV-infected MSM. Beta HPVs were significantly more common than alpha types (53.8% vs. 23.9% for HIV-infected subjects, p < 0.0001; 50.3% vs. 17.1% for HIV-uninfected subjects, p < 0.0001). Gamma HPVs were also frequently detected (30.8% and 25.9% in HIV-infected and uninfected MSM, respectively). NGS produced 2,620,725 reads representative of 146 known HPVs (16 alpha-PVs, 53 beta-PVs, 76 gamma-PVs, one unclassified) and eight putative new HPVs, taxonomically assigned to the beta genus. The oral cavity contains a wide spectrum of HPVs, with beta types representing the predominant genus. The prevalence of beta and gamma HPVs is high even in immunorestored HIV-infected individuals. NGS confirmed the abundance of cutaneous HPVs and identified some putative novel beta HPVs. This study confirms that cutaneous HPVs are frequently present at mucosal sites and highlights that their pathological role deserves further investigation since it may not be limited to skin lesions.

Evidence for swine and human papillomavirus in pig slurry in Italy

AIMS

The diversity and the geographical distribution of swine papillomaviruses (PVs) are virtually unknown. The occurrence and the diversity of swine PV were therefore investigated in pig slurry collected in Italy, to contribute towards filling this gap in knowledge.

METHODS AND RESULTS

Twenty-two slurry samples underwent analysis by nested PCR and DNA sequencing using published and newly designed specific primer pairs for Sus scrofa papillomavirus (SsPV) type 1 and 2 (SsPV1 and 2), along with degenerate PV-specific primers targeting the major coat protein L1 and the helicase protein E1. Overall, three samples (13·6%) were positive for SsPV1 by specific primers, and nucleotide (nt) sequences showed 99-100% nt identity with SsPV1 variant a (EF395818), while SsPV2 was not found in any sample. Using generic primers, eight samples (36·4%) were tested positive for human papillomavirus (HPV), and were characterized as follows: β1-HPV8, β1-HPV14, β1-HPV206, β2-HPV113, β2-HPV120 and γ1-HPV173. Moreover, one unclassified γ-type was detected.

CONCLUSIONS

Both swine and human PVs were detected in pig slurry in this study. The unexpected presence of HPV in pig waste could be explained as the result of an improper use of the sewage collection pits and/or with improper procedures of the operators.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study reports the first detection of SsPV1 in Italy, along with the first detection of HPVs in pig slurry samples in Italy, and expands our knowledge about PV diversity and geographic distribution.