Persistence of Betapapillomavirus Infections as a Risk Factor for Actinic Keratoses, Precursor to Cutaneous Squamous Cell Carcinoma

HPV transcription in skin tumors

BACKGROUND

Although more than 95% of viral sequences found in skin tumors typically belong to human papillomaviruses (HPVs), HPV transcription has so far not been detected. As current technology allows very deep transcriptome sequencing, we examined skin tumors and precursor lesions for HPV transcription.

METHOD

Fresh frozen biopsies from 12 skin specimens (11/12 were positive for HPV DNA) were subjected to total RNA sequencing. The cervical cancer cell line CaSki was included as a positive control for HPV transcription.

RESULTS

HPV RNA was detected and confirmed in 1/12 skin lesions at a median depth of 66 million reads per sample. One specimen was positive for HPV 110 transcripts mapping to E6, E7, E2/E4 and L2 open reading frames, as well as to a spliced E1^E4 transcript.

CONCLUSION

In conclusion, the study revealed that a minority of skin lesions contains HPV transcripts and that HPV DNA detection does not predict HPV transcriptional activity.

An Emerging Issue in Oncogenic Virology: the Role of Beta Human Papillomavirus Types in the Development of Cutaneous Squamous Cell Carcinoma

Evidence suggests that beta human papillomaviruses (HPVs), together with ultraviolet radiation, contribute to the development of cutaneous squamous cell carcinoma. Beta HPVs appear to be not the main drivers of carcinogenesis but rather facilitators of the accumulation of ultraviolet-induced DNA mutations. Beta HPVs are promoters of skin carcinogenesis, although they are dispensable for the maintenance of the malignant phenotype. Therefore, beta HPV represents a target for skin cancer prevention, especially in high-risk populations.

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.

Cancer risks after solid organ transplantation and after long-term dialysis

Immunosuppression involves an inability to control virus infections and increased incidence of virus-associated cancers. Some cancers without known viral etiology are also increased, but data on exactly which cancer forms are increased has been inconsistent. To provide a reliable and generalizable estimate, with high statistical power and long follow-up time, we assessed cancer risks using comprehensive, population-based registries in two different countries and from two different immunosuppressed patient groups (solid organ transplant recipients (OTRs) and long-term dialysis patients (LDPs)). National registries in Denmark and Sweden identified 20,804 OTRs and 31,140 LDPs that were followed up using national cancer registries. Standardized incidence ratios (SIR) compared to the general population were estimated. We found highly similar results, both for the two different countries and for the two different immunosuppressed cohorts, namely an increased incidence for the following specific cancer forms: Non-melanoma skin cancer (NMSC), non-Hodgkin's lymphoma and cancers of the lip, kidney, larynx and thyroid. The SIR for overall cancer among OTRs was 3.5 [n = 2,142, 95% CI, 3.4-3.7] in Sweden, 2.9 [n = 1,110, 95% CI, 2.8-3.1] in Denmark and 1.6 [n = 1,713, 95% CI, 1.5-1.6] among LDP. The SIR for NMSC among OTRs was 44.7 [n = 994, 95% CI, 42-47.5] in Sweden and 41.5 [n = 445, 95% CI, 37.8-45.5] in Denmark. The increased SIR for NMSC among LDPs was 5.3 [n = 304, 95% CI, 4.7-5.9]). In summary, an increased SIR for a specific, similar set of cancer forms is consistently found among the immunosuppressed. Conceivable explanations include surveillance bias and immunosuppression-related susceptibility to viral infections.

Improved detection reveals active β-papillomavirus infection in skin lesions from kidney transplant recipients

The aim of this study was to determine whether detection of β-HPV gene products, as defined in epidermodysplasia verruciformis skin cancer, could also be observed in lesions from kidney transplant recipients alongside the viral DNA. A total of 111 samples, corresponding to 79 skin lesions abscised from 17 kidney transplant recipients, have been analyzed. The initial PCR analysis demonstrated that β-HPV-DNA was highly present in our tumor series (85%). Using a combination of antibodies raised against the E4 and L1 proteins of the β-genotypes, we were able to visualize productive infection in 4 out of 19 actinic keratoses, and in the pathological borders of 1 out of 14 squamous cell carcinomas and 1 out of 31 basal cell carcinomas. Increased expression of the cellular proliferation marker minichromosome maintenance protein 7 (MCM7), that extended into the upper epithelial layers, was a common feature of all the E4-positive areas, indicating that cells were driven into the cell cycle in areas of productive viral infections. Although the present study does not directly demonstrate a causal role of these viruses, the detection of E4 and L1 positivity in actinic keratosis and the adjacent pathological epithelium of skin cancer, clearly shows that β-HPV are actively replicating in the intraepidermal precursor lesions of kidney transplant recipients and can therefore cooperate with other carcinogenic agents, such as UVB, favoring skin cancer promotion.

Betapapillomaviruses in the anal canal of HIV positive and HIV negative men who have sex with men

BACKGROUND

Betapapillomaviruses (β-PV) are etiologically associated with epidermodysplasia verruciformis and a proportion of skin precancerous lesions and cancer, mainly in immunocompromised individuals.

OBJECTIVES

The prevalence and persistence of anal β-PV infection and β-PV type distribution were determined in a cohort of men who have sex with men (MSM). A correlation with HIV-1 infection status and selected demographic and behavioral risk factors were additionally established.

STUDY DESIGN

A total of 181 anal swabs (135 initial and 46 follow-up swabs) obtained from 135 Slovenian MSMs (17.0% HIV-1 positive) were tested for the presence of 25 different β-PV types using Diassay RHA Kit Skin (beta) HPV assay and, if negative, with an in-house nested M(a)/H(a) PCR.

RESULTS

β-PVs were detected in 88/135 (65.2%) initial anal swabs. Infection with multiple β-PV types was found in 26 samples; the number of β-PVs ranged from 2 to 9. A total of 29 distinct β-PVs were detected: HPV-36 and HPV-38 were the most prevalent, followed by HPV-23, HPV-24, and HPV-93. HIV-1 positive status, promiscuity and use of alkyl nitrites were significantly associated with a higher prevalence of anal β-PV infection. Three partial DNA sequences suggesting putative new HPV types were identified.

CONCLUSION

To the best of our knowledge, this is the first study to investigate and characterize β-PV infections in the anal region. We showed that anal β-PV infection is highly prevalent in the MSM population and that β-PVs can establish persistent infection in the anal region for up to 4.8 years.

Human papillomavirus status in extragenital nonmelanoma skin cancers

About 5% of all cancers worldwide can be attributed to human papillomaviruses (HPVs); namely, six sites are strongly associated with HPV infections: cervix, penis, vulva, vagina, anus, and oropharynx. Nonmelanoma skin cancers (NMSC), basal cell carcinoma (BCC), and squamous cell carcinoma (SCC) are the most common malignancies in Caucasians. In fact, there is an intense connection between sunlight exposure, fair skin, HPV, and development of NMSC. We have conducted a pilot study that included tissue samples from 26 carcinoma patients, of which there were 13 BCC and 13 SCC. HPV detection and typing was done with DNA amplification and sequencing, respectively. In total, 23.1% of SCC samples (3/13) and 7.7% of BCC samples (1/13) were positive for HPV DNA. The importance of understanding all aspects of NMSC carcinogenesis may be to reveal novel therapeutic options or preventive measures for HPV containing NMSC patients.

Cutaneous squamous cell carcinoma: defining the high-risk variant

With a lifetime incidence of approximately 10% in the general population, cutaneous squamous cell carcinoma (CSCC) is the second most common type of nonmelanoma skin cancer. Most CSCCs are benign and can be completely eradicated by surgery or other dermatological procedures. There is, however, a subgroup associated with an increased likelihood of lymph node metastases and, therefore, with high morbidity and mortality. This article analyzes the various factors that define aggressive CSCC. We propose a method for defining high-risk SCC on the basis of a series of major and minor criteria. This method will allow better prognostic evaluation and enable personalized management of patients with high-risk SCC, possibly leading to improved overall survival.

Cutaneous squamous cell carcinoma in the cat: current understanding and treatment approaches

PRACTICAL RELEVANCE

Squamous cell carcinoma (SCC) is a tumour that commonly involves the skin or oral cavity and is, therefore, an important differential diagnosis for any cutaneous lesion(s), especially any non-healing scabbing lesions on the eyelids, nasal planum or ears of light-coloured cats.

CLINICAL CHALLENGES

Superficial lesions of the nasal planum, discrete small eyelid lesions and lesions on the tips of pinnae are relatively easily treated, but higher stage lesions are more challenging to manage and may compromise the cosmetic appearance of the cat.

AUDIENCE

This review article is aimed at all veterinary practitioners that see cats.

EVIDENCE BASE

The review summarises the peer-reviewed literature relating to our understanding of feline cutaneous SCC. Unfortunately, the literature is limited and in need of updating in areas.

Eyebrow hairs from actinic keratosis patients harbor the highest number of cutaneous human papillomaviruses

BACKGROUND

Cutaneous human papillomavirus (HPV) infections seem to be associated with the onset of actinic keratosis (AK). This study compares the presence of cutaneous HPV types in eyebrow hairs to those in tissues of normal skin and skin lesions of 75 immunocompetent AK patients.

METHODS

Biopsies from AK lesions, normal skin and plucked eyebrow hairs were collected from each patient. DNA from these specimens was tested for the presence of 28 cutaneous HPV (betaPV and gammaPV) by a PCR based method.

RESULTS

The highest number of HPV prevalence was detected in 84% of the eyebrow hairs (63/75, median 6 types) compared to 47% of AK lesions (35/75, median 3 types) (p< 0.001) and 37% of normal skin (28/75, median 4 types) (p< 0.001), respectively. A total of 228 HPV infections were found in eyebrow hairs compared to only 92 HPV infections in AK and 69 in normal skin. In all three specimens HPV20, HPV23 and/or HPV37 were the most prevalent types. The highest number of multiple types of HPV positive specimens was found in 76% of the eyebrow hairs compared to 60% in AK and 57% in normal skin. The concordance of at least one HPV type in virus positive specimens was 81% (three specimens) and 88-93% of all three combinations with two specimens.

CONCLUSIONS

Thus, eyebrow hairs revealed the highest number of cutaneous HPV infections, are easy to collect and are an appropriate screening tool in order to identify a possible association of HPV and AK.

Actinic keratosis: a clinical and epidemiological revision

Actinic keratoses are benign intraepithelial skin neoplasms constituted by atypical proliferation of keratinocytes that may evolve to squamous cell carcinoma. They develop in photoexposed skin areas; they are induced mainly by ultraviolet radiation and are considered cutaneous markers of chronic exposure to sunlight. They develop mainly in adults and older, fair skinned individuals, and are the fourth most common cause of dermatologic consultation in Brazil. Damage to the apoptosis pathway in photoexposed epithelium favors cellular proliferation and the permanence of the lesions. In this revision, the authors assemble the main epidemiological data regarding this disease and suggest that strategies to identify risky phenotypes, early diagnosis, adequate treatment, clinical follow-up, stimulus to skin self examination, photoeducation and photoprotection should be promoted with the aim of avoiding the progression to malignancy and also the prevention and the diagnose of concomitant neoplasms also induced by ultraviolet radiation.

Prospective study of human papillomavirus seropositivity and risk of nonmelanoma skin cancer

Cutaneous human papillomaviruses (HPVs) have been associated with squamous cell carcinoma (SCC) in case-control studies, but there are limited data from prospective studies assessing whether virus exposure predicts risk of future cancer development. Two major biobanks, the Southern Sweden Microbiology Biobank (1971-2003) and the Janus Biobank (1973-2003) in Norway, containing samples from 850,000 donors, were searched for incident skin cancer for up to 30 years using registry linkages. Altogether, 2,623 donors with samples taken before diagnosis of SCC or basal cell carcinoma (BCC) of the skin were identified. Prediagnostic samples and samples from 2,623 matched controls were tested for antibodies against 33 types of HPV. Baseline seropositivity to HPV types in genus β species 2 was associated with SCC risk (odds ratio = 1.3, 95% confidence interval: 1.1, 1.7); this was also the case for samples taken more than 18 years before diagnosis (odds ratio = 1.8, 95% confidence interval: 1.1, 2.8). Type-specific persistent seropositivity entailed elevated point estimates for SCC risk for 29 HPV types and decreased point estimates for only 3 types. After multiple hypothesis adjustment, HPV 76 was significantly associated with SCC risk and HPV 9 with BCC risk. In summary, seropositivity for certain HPV types was associated with an increased risk for future development of SCC and BCC.

Human papillomavirus 8 E6 disrupts terminal skin differentiation and prevents pro-Caspase-14 cleavage

Expression of the betapapillomavirus (betaPV) E6/E7 genes has been shown to impair both keratinocyte differentiation and apoptosis. Especially late-terminal keratinocyte differentiation shares certain aspects with apoptosis, such as fragmentation of DNA and activation of caspases. Here we investigated the disruption of keratinocyte differentiation in organotypic skin (raft) cultures of primary (PHK) and immortalized (N/TERT) human keratinocytes, in particular by human papillomavirus (HPV)8. Immunohistochemical analysis of HPV5 and HPV8 E6/E7-expressing PHK revealed thickening of the rafts and complete absence of stratum corneum formation, even after 18 days of culture. This phenotype was confirmed in N/TERT raft cultures. When expressed separately, the aberrant morphology was observed only in rafts expressing E6, not E7. Immunofluorescence analysis of HPV8 E6 PHK rafts showed an increase in number and size of Filaggrin- and Caspase-14-positive cells in the granular layer. In raft lysates analyzed by western-blot, the presence of pro-Caspase-14 in the differentiated keratinocytes was confirmed, but in the HPV8 E6 rafts none of the Caspase-14 subunits were detected. In conclusion, in the raft system, HPV8 E6 prevented late-terminal keratinocyte differentiation resulting in an accumulation of Filaggrin and pro-Caspase-14-positive cells in the absence of stratification. This differentiation arrest was accompanied by the failure to express Caspase-14 subunits, suggesting absence of Caspase-14 activation and probable abrogation of Filaggrin maturation in HPV8 E6-expressing keratinocytes.

Factors associated with the seroprevalence of 26 cutaneous and two genital human papillomavirus types in organ transplant patients

Viral skin infections are commonly present in organ transplant recipients (OTR). In this study, we aimed to identify factors associated with human papillomavirus (HPV) infections in OTR. Patients with solid-organ transplants were recruited from the outpatient nephrology and dermatology clinics in five European countries. Only patients with no current or past skin cancer were included in this analysis. Serum samples were analysed for antibodies to the L1 proteins of 26 cutaneous and two genital HPV types from five phylogenetic genera (α, β, γ, μ and ν). The most consistent association was found between recreational sun exposure and the seroprevalence of all tested genera, except α. The antibody presence of any β type was higher among people who had been transplanted at least 23 years prior to participation than in those who had been transplanted for less than 7 years. The prevalence of two γ-HPV types (60 and 65) and three β-HPV types (15, 38 and 49) was associated with time since transplantation. The presence of a high number of warts was associated with the presence of any μ-PV or ν-PV types, and having greater than 50 keratotic skin lesions was almost significantly associated with the presence of antibodies to two or more γ-PV. Discrepancies in the results of the present study, as well as in previous reports, may depend on different methodologies and on geographical variations. Our results also indicate that further research with more standardized methods is needed to clarify the role of cutaneous HPV in OTR.

The Association between cutaneous squamous cell carcinoma and betapapillomavirus seropositivity: a cohort study

BACKGROUND

It is currently unclear whether betapapillomaviruses (betaPV) play a role in the etiology of cutaneous squamous cell carcinoma (SCC). We investigated the association between betaPV antibodies and subsequent SCC in a population-based cohort study.

METHODS

Serum samples were collected in 1992 and/or 1996 from 1,311 participants of the community-based Nambour Skin Cancer Study. These were tested for the presence of L1 antibodies against 21 different betaPV types. Histologically diagnosed SCCs were ascertained through three full-body skin examinations and linkage with the local pathology laboratories. We used age- and sex-adjusted Cox proportional hazards models to analyze the relationship between betaPV antibodies and SCC occurrence from 1992 until 2007.

RESULTS

SCC was newly diagnosed in 150 people. No associations were found between the presence of any betaPV L1 antibodies and the occurrence of SCC (HR = 1.0), and stratification by sex, skin color, and sunburn propensity did not affect these results. However, among people who were less than 50 years old in 1992, the presence of betaPV antibodies was associated with a two-fold increased risk of SCC. There was no significant association between antibodies to any individual betaPV type examined and the later development of SCC.

CONCLUSIONS

Whether betaPV infection of the skin, and indirectly betaPV antibodies, are involved in the oncogenic process in the general population remains unclear, and this longitudinal study provides only limited support.

IMPACT

This study emphasizes the need for additional longitudinal studies of HPV (human papilloma virus) and SCC, to avoid the possibility of reverse causality in case--control studies.

The combined influence of oral contraceptives and human papillomavirus virus on cutaneous squamous cell carcinoma

The vast majority of cutaneous squamous cell carcinoma (CSCC) will occur in those with fair complexion, tendency to burn, and high ultraviolet radiation (UVR) exposure. Organ transplant recipients also are an important population at great risk for CSCC. An association has been reported between oral contraceptive (OC) use, human papillomavirus virus (HPV) and cervical cancer, and there could be a similar association for CSCC. The cutaneous HPV β-E6 protein, a close cousin of the transformative E6 protein underlying anogenital cancers, has been shown to inhibit apoptosis in response to UVR damage and stimulate morphologic transformation in rodent fibroblast cell lines. Furthermore, OC use has been shown to enhance HPV transcription and may contribute to CSCC risk through this pathway.

Enhanced StefinA and Sprr2 expression during papilloma formation in HPV8 transgenic mice

BACKGROUND

The human papillomavirus type 8 (HPV8) is associated with the development of non-melanoma skin cancer. Transgenic mice expressing the complete early gene region of HPV8 (E6/E7/E1/E2/E4=CER) or E6 separately under the control of the keratin14 promoter spontaneously developed papillomas characterized by varying degrees of epidermal dysplasia. Papilloma growth could be synchronized by a single UVA/B irradiation of the skin, which led to the development of papillomas within three weeks.

OBJECTIVE

The objective of this study was to identify alterations in cellular gene expression correlated with HPV8 oncogene expression in transgenic mice.

METHODS

We applied global gene expression profiling by microarray analysis and confirmed deregulation of cellular genes by qRT-PCR and immunohistochemical analysis.

RESULTS

By comparison of non-lesional HPV8-CER skin with skin of the parental mouse strain FVB/n, two cellular genes, namely StefinA and Sprr2, coding for precursor proteins of the cornified envelope, were predicted to be strongly upregulated in transgenic skin, which could be confirmed in subsequent qRT-PCR experiments. StefinA and Sprr2 mRNA expression was enhanced until day 7 after UV treatment with higher levels in HPV8 positive skin. While the expression of both genes returned to a normal level in the course of epidermis regeneration in wt mice, the expression persisted elevated in hyperplastic transgenic skin. Staining of an UV induced papilloma of FVB/n wt mouse revealed also strong expression of StefinA and Sprr2 indicating that upregulation in later stages of papilloma formation is independent of HPV8.

CONCLUSION

In non-lesional HPV8-CER transgenic skin StefinA and Sprr2 were found to be indirect/direct transcriptional targets of HPV8.

Infection, stem cells and cancer signals

The association of cancer with preceding parasitic infections has been observed for over 200 years. Some such cancers arise from infection of tissue stem cells by viruses with insertion of viral oncogenes into the host DNA (mouse polyoma virus, mouse mammary tumor virus). In other cases the virus does not insert its DNA into the host cells, but rather commandeers the metabolism of the infected cells, so that the cells continue to proliferate and do not differentiate (human papilloma virus and cervical cancer). Cytoplasmic Epstein Barr virus infection is associated with a specific gene translocation (Ig/c-myc) that activates proliferation of affected cells (Burkitt lymphoma). In chronic osteomyelitis an inflammatory reaction to the infection appears to act through production of inflammatory cytokines and oxygen radical formation to induce epithelial cancers. Infection with Helicobacter pylori leads to epigenetic changes in methylation and infection by a parasite. Clonorchis sinensis also acts as a promoter of cancer of the bile ducts of the liver (cholaniocarcinoma). The common thread among these diverse pathways is that the infections act to alter tissue stem cell signaling with continued proliferation of tumor transit amplifying cells.

Lack of association between the presence and persistence of betapapillomavirus DNA in eyebrow hairs and betapapillomavirus L1 antibodies in serum

Betapapillomavirus (betaPV) DNA and seroresponses are highly prevalent in the general population and both are frequently used as infection markers in epidemiological studies to elucidate an association with cutaneous squamous cell carcinoma (SCC). Little is known about the natural history of betaPV infection and the aspects of infection that drive antibody responses. To investigate the relationship between these markers, this study assessed whether the presence or persistence of betaPV DNA in eyebrow hairs and L1 antibodies of the same betaPV type co-occurred more frequently than would be expected by chance in both a cross-sectional assessment and a longitudinal study. betaPV DNA in plucked eyebrow hairs and L1 antibodies in serum were measured in 416 participants of the Australian community-based Nambour Skin Cancer Study in 1996. Similar data were available for a subset of 148 participants in 2003. Observed co-occurrence of betaPV DNA and antibodies was compared with expected values based on prevalence. A case-wise concordance index was used to calculate the overall concordance of betaPV DNA and antibodies of the same type. No significant associations were found between the presence or persistence of betaPV DNA and antibody responses. The age and sex of the host did not influence the association, and nor did SCC status or a history of sunburns. It was concluded that betaPV antibody responses in adults are not primarily driven by betaPV infection as measured in eyebrow hairs. Other factors, such as viral load, may play a more pivotal role in the induction of detectable seroresponses.