Cutaneous Human Papillomaviruses and the Risk of Keratinocyte Carcinomas.

Cutaneous human papillomavirus (cuHPV) infections may be novel targets for skin cancer prevention and treatment, but critical information regarding the development of virus-positive skin cancers following cuHPV infection has been lacking. In this study, baseline cuHPV infection was measured by serology and viral DNA detection in eyebrow hairs (EBH) and forearm skin swabs (SSW) among 1,008 individuals undergoing routine skin cancer screening exams and followed for incidence of basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cuSCC). Baseline ß-HPV detection, particularly in SSW, significantly predicted cuSCC (HR = 4.32; 95% confidence interval, 1.00-18.66), whereas serologic evidence of past ß-HPV infection was not associated with cuSCC. Less than 5% of baseline ß-HPV types detected in SSW were present in subsequent cuSCC tumors, and cuHPV detected in SSW with higher mean fluorescence intensity values were more likely to be present in cuSCC compared with those with lower levels (P < 0.001). ß-HPV-positive cuSCC occurred more often in areas of highly sun-damaged skin than did ß-HPV-negative cuSCC. Overall, no clear patterns were observed between baseline ß-HPV detection and subsequent development of BCC, or between baseline γ-HPV detection and either cuSCC or BCC. Collectively, these results demonstrate that ß-HPV detection in SSW is a significant predictor of cuSCC risk, although evidence suggests only a small subset of cuSCC is etiologically linked to ß-HPV infection. SIGNIFICANCE: ß-HPV positivity may be a useful biomarker for identifying individuals who could benefit from increased screening or novel cutaneous squamous cell carcinoma prevention strategies.

Pigmented viral plaque and basal cell tumor associated with canine papillomavirus infection in Pug dogs.

Pigmented viral plaque is most commonly seen in Pug dogs in association with canine papillomavirus (CPV). In the present study, nucleic acid sequence and localization of viral genes were examined in 4 cases of pigmented viral plaque in Pug dogs. The results of polymerase chain reaction and nucleic acid sequence analysis showed that the 3 cases with pigmented viral plaque were infected with CPV4, and 1 case with CPV18. In the case with CPV18-positive viral plaque, CPV18 gene was also detected in a lesion of cytokeratin-14- and P63-positive basal cell tumor that developed adjacent to a pigmented viral plaque. Moreover, CPV gene was detected in the squamous cells of pigmented viral plaques and the neoplastic cells of basal cell tumor by in situ hybridization. This is the first report of basal cell tumor associated with CPV18-infection in the dog. Infection of CPV18 may be associated with development of basal cell tumor.

Transformation of enriched mammary cell populations with polyomavirus middle T antigen influences tumor subtype and metastatic potential.

INTRODUCTION: Breast cancer exhibits significant molecular, histological, and pathological diversity. Factors that impact this heterogeneity are poorly understood; however, transformation of distinct normal cell populations of the breast may generate different tumor phenotypes. Our previous study demonstrated that the polyomavirus middle T antigen (PyMT) oncogene can establish diverse tumor subtypes when broadly expressed within mouse mammary epithelial cells. In the present study, we assessed the molecular, histological, and metastatic outcomes in distinct mammary cell populations transformed with the PyMT gene. METHODS: Isolated mouse mammary epithelial cells were transduced with a lentivirus encoding PyMT during an overnight infection and then sorted into hormone receptor-positive luminal (CD133+), hormone receptor-negative luminal (CD133-), basal, and stem cell populations using the cell surface markers CD24, CD49f, and CD133. Each population was subsequently transplanted into syngeneic cleared mouse mammary fat pads to generate tumors. Tumors were classified by histology, estrogen receptor status, molecular subtype, and metastatic potential to investigate whether transformation of different enriched populations affects tumor phenotype. RESULTS: Although enriched mammary epithelial cell populations showed no difference in either the ability to form tumors or tumor latency, differences in prevalence of solid adenocarcinomas and squamous, papillary, and sebaceous-like tumors were observed. In particular, squamous metaplasia was observed more frequently in tumors derived from basal and stem cells than in luminal cells. Interestingly, both molecularly basal and luminal tumors developed from luminal CD133+, basal, and stem cell populations; however, luminal CD133- cells gave rise exclusively to molecularly basal tumors. Tumors arising from the luminal CD133-, basal, and stem cell populations were highly metastatic; however, luminal CD133+ cells generated tumors that were significantly less metastatic, possibly due to an inability of these tumor cells to escape the primary tumor site. CONCLUSIONS: Expression of PyMT within different mammary cell populations influences tumor histology, molecular subtype, and metastatic potential. The data demonstrate that luminal CD133+ cells give rise to less metastatic tumors, luminal CD133- cells preferentially establish basal tumors, and the cell of origin for squamous metaplasia likely resides in the basal and stem cell populations.

Prevalence of MCPyV in Merkel cell carcinoma and non-MCC tumors.

BACKGROUND: Merkel cell polyomavirus (MCPyV) is the likely causative agent of Merkel cell carcinoma (MCC). However, the prevalence of MCPyV in non-MCC population and its possible role in the pathogenesis of other skin cancers are not known yet. METHODS: A molecular pathology study was performed in 33 MCC samples and 33 age- and sex-matched samples of sun exposed non-MCC tumors [12 seborrheic keratoses (SK), 11 basal cell carcinomas (BCC) and 10 lentigo maligna melanomas (LMM)]. All tumors were analyzed for presence of MCPyV-DNA by polymerase chain reaction (PCR) and Southern-Blot hybridization of PCR products. RESULTS: MCPyV sequences were detected in 21 MCC samples (64%) and in 2 non-MCC tumors of sun exposed skin (6%; both SK-patients). Neither the tissue samples from BCC nor LMM proved positive for MCPyV sequences. CONCLUSION: We were able to confirm prior data on prevalence of MCPyV-DNA in MCC. Furthermore, a female predominance of MCPyV-positive MCC-patients was detected. There was no relevant association of MCPyV with SK, BCC and LMM. Speculative, prevalence of MCPyV in an age- and sex-matched non-MCC population could average up to 6%.

Detection of human papillomavirus infection in trichilemmomas and verrucae using in situ hybridization.

BACKGROUND: It is hypothesized that trichilemmomas are 'burned out' verrucae. By performing in situ hybridization using HPV type-specific probes, we explored this concept. METHODS: Verrucae vulgaris and plantaris were positive controls, and inverted follicular keratoses (IFKs) were negative controls. Additionally, all lesions were tested for HPV genital types (low and high risk). RESULTS: We analyzed 9 trichilemmomas, 20 verrucae vulgaris, 8 verrucae plana, 3 verrucae plantaris and 6 IFKs. All trichilemmomas were negative for HPV types 1, 2 and genital types. Conversely, 9/20 verrucae vulgaris, 2 verrucae plantaris, and 1 verruca plana were positive for HPV type 2. Among HPV-2 positive lesions, 2/2 verrucae plantaris and 1 verruca vulgaris (chin) were strongly positive for genital-type HPV. One verruca plana (shin) was positive for genital-type HPV only. All 6 IFKs were HPV negative. CONCLUSIONS: Using HPV type 1 and 2-specific probes and mixed genital-type probes, we were unable to detect HPV in trichilemmomas. This suggests that HPV-1, HPV-2 and low and high risk genital-type HPVs are not involved in the histogenesis of trichilemmoma. We also showed that genital HPV types could be present in non-genital verrucae.

Detection of HPV DNA in trichilemmomas by polymerase chain reaction.

Paraffin sections of 11 formalin-fixed trichilemmomas were investigated for the presence of human papillomavirus (HPV) DNA by the polymerase chain reaction (PCR) with the degenerated consensus primer pairs. PCRs were conducted with different annealing temperatures. When the annealing temperature was reduced from 55 degrees C to 50 degrees C, amplification products of the expected size were obtained for all 11 cases investigated. Determination of the HPV type was performed by cloning and sequencing of the amplification products. The sequence analysis of the eleven cloned amplicons gave the following data: based on sequence comparison with published amino acid sequences, the best homology was found to epidermodysplasia verruciformis (EV)-associated HPVs (supergroup B). In four specimens an HPV type 23 related type was found; five specimens contained HPV sequences which did not match with one of the known HPV types, but had the closest homology to HPV types 15, 17, and 37. Three of the HPV variants which had not been characterised, displayed identical sequences. Two additional HPV amplification fragments displayed played 100% homology to HPV-6b. These results demonstrate, for the first time, the presence of HPV DNA in trichilemmomas. The sequence data suggest that HPV variants or types in trichilemmoma are members of the EV-associated HPV supergroup B.

Human papillomavirus is associated with the frequent detection of warty and basaloid high-grade neoplasia of the vulva and cervical neoplasia among immunocompromised women.

A total of 158 women who either HIV-infected or under iatrogenic immunosuppression were examined regularly during a 4-year period to evaluate if certain vulvar neoplasms and cervical neoplasia have similar associated risk factors. Patients with CIN were matched prospectively with immunocompetent controls with CIN. Forty-eight cervical lesions were detected among patients, including 2 invasive carcinoma and 15 CIN-3 lesions, compared to 11 vulvar lesions, including 2 invasive carcinoma and 7 VIN-3 lesions. Women who have more than five life-time partners were more likely to have HPV-DNA positive cervical swabs and vulvar scrapes as well as cervical and/or vulvar neoplasia. Compared to 2.7% of controls 15.2% of patients with CIN had coexisting high-grade lesions of the vulva. With 1 exception all patients with vulvar neoplasia either suffered from symptomatic immunodeficiency or received immunosuppressive drugs for more than 10 years. Except for 1 VIN-3 lesions, all vulvar neoplasms were associated with HPV-DNA types 16, 31, and/or 33. Six of nine patients as well as the 2 controls with coexisting vulvar and cervical neoplasia had the same HPV-type associated with both lesions. All vulvar lesions were classified as either "warty" or "basaloid". In conclusion cervical and bowenoid/basaloid vulvar neoplasia seem to have a similar HPV-related genesis. Malfunction of the cellular immune response appears to be a cofactor in the genesis of HPV-associated neoplasia at both sites.