Merkel cell polyomavirus large T antigen is detected in rare cases of nonmelanoma skin cancer

Merkel cell polyomavirus and its etiological relationship with skin tumors

Viruses have been frequently identified in several human neoplasms, but the etiological role of these viruses in some tumors is still a matter of controversy. Polyomaviruses stand out among the main viruses with oncogenic capacity, specifically the Merkel cell polyomavirus (MCPyV). Recent revisions in the taxonomy of polyomaviruses have divided the Polyomaviridae family into six genera, including 117 species, with a total of 14 currently known human-infecting species. Although the oncogenicity of polyomaviruses has been widely reported in the literature since 1950, the first description of a polyomavirus as an etiological agent of a neoplasm in humans was made only in 2008 with the description of MCPyV, present in approximately 80% of cases of Merkel cell carcinoma (MCC), with the integration of its genome to that of the tumor cells and tumor-specific mutations, and it is considered the etiological agent of this neoplasm since then. MCPyV has also been detected in keratinocyte carcinomas, such as basal cell carcinoma and squamous cell carcinoma of the skin in individuals with and without immunosuppression. Data on the occurrence of oncogenic viruses potentially involved in oncogenesis, which cause persistence and tissue injury, related to the Merkel cell polyomavirus are still scarce, and the hypothesis that the Merkel cell polyomavirus may play a relevant role in the genesis of other cutaneous carcinomas in addition to MCC remains debatable. Therefore, the present study proposes to explore the current knowledge about the presence of MCPyV in keratinocyte carcinomas.

Quantitative analysis of Merkel cell polyomavirus (MCPyV) genome in non-melanoma skin cancer and normal tumor margins

Merkel cell polyomavirus (MCPyV) is the cause of approximately 80% of Merkel cell carcinomas (MCC). The common types of non-melanoma skin cancer (NMSC) including squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) are histologically similar to MCC. In the present study, 58 NMSC formalin-fixed paraffin-embedded tissue (FFPE) samples including 12 SCC, 46 BCC, and 58 FFPE samples of adjacent non-tumoral margins as the control were included. Determination of large tumor antigens (LTAg) copy number was performed by qReal-Time PCR as a viral copy number per cell to elucidate MCPyV carcinogenic role in non-melanoma skin cancer. Out of 58 samples, 36 (62%) cancerous and 22 (37.9%) normal tumor margins were positive for MCPyV LTAg. Median copy numbers of MCPyV LTAg among all NMSC samples and non-tumoral margins were 0.308×10-2 and 0.269×10-3 copies per cell respectively (P=0.001). In addition, although the viral load in the majority of samples was detected to be lower than one copy per cell, in 4 BCC samples, a viral load higher than one LTAg copy per cell was detected. The present study revealed that the detection of higher levels of MCPyV LTAg viral load in some BCC and SCC samples may be correlated with the role of MCPyV in some cases of BCC and SCC skin cancer.

Prevalence of Merkel Cell Polyomavirus in Normal and Lesional Skin: A Systematic Review and Meta-Analysis

The prevalence of Merkel cell polyomavirus(MCPyV) in Merkel cell carcinoma(MCC) and non-MCC skin lesions and its possible role in the etiology of other skin diseases remain controversial. To systematically assess the association between MCPyV infection and MCC, non-MCC skin lesions, and normal skin. For this systematic review and meta-analysis, a comprehensive search for eligible studies was conducted using Medline Ovid, Pubmed, Web of Science, and the Cochrane CENTRAL databases until August 2021; references were searched to identify additional studies. Observational studies that investigated the association between MCPyV infection and MCC, non-MCC skin lesions, and normal skin using polymerase chain reaction(PCR) as a detection method and provided sufficient data to calculate the prevalence of MCPyV positivity. A total of 50 articles were included in the study after exclusion criteria were applied. Two reviewers independently reviewed and assessed the eligibility of the studies, and all disagreements were resolved by consensus. To determine the association between MCPyV and MCC, overall odds ratio (OR) were calculated with 95% CI using a random-effects model. Single-arm meta-analyses were performed to examine the prevalence rate of MCPyV+ in MCC, non-MCC skin lesions, and normal skin. The primary analysis was the prevalence rate of MCPyV+ in MCC. Secondary outcomes included the prevalence rate of MCPyV+ in non-MCC skin lesions and normal skin. A total of 50 studies involving 5428 patients were reviewed based on our inclusion and exclusion criteria. Compared with the control group, MCPyV infection was significantly associated with MCC (OR = 3.51, 95% CI = 2.96 - 4.05). The global prevalence of MCPyV+ in MCC, melanoma, squamous cell carcinoma, basal cell carcinoma, Bowen's disease, actinic keratosis, keratoacanthoma, seborrheic keratosis, and normal skin was 80%, 4%, 15%, 15%, 21%, 6%, 20%, 10%, and 11%, respectively. The current results suggest that MCPyV infection is significantly associated with an increased risk of MCC. However, the low prevalence rate of MCPyV+ in non-MCC skin lesions does not exclude a pathogenic association of this virus with the development of non-MCC skin lesions.

Merkel cell polyomavirus and non-Merkel cell carcinomas: guilty or circumstantial evidence?

Merkel cell polyomavirus (MCPyV) is the major causative factor of the rare but aggressive cancer, Merkel cell carcinoma (MCC). Two characteristics of MCPyV-positive MCCs are integration of the viral genome and expression of a truncated version of one of its oncogenic proteins, namely large T antigen. The strong association of MCPyV with MCC development has incited researchers to further investigate a possible role of this virus in other cancers. However, many of the examples displaying the presence of the virus in the various non-MCC cancers are not able to clearly demonstrate a direct connection between cellular transformation and the presence of the virus. The prevalence of the virus is significantly lower in non-MCC cancers compared to MCCs, with a lower level of viral load and sparse viral protein expression. Moreover, the state of the viral genome, and whether a truncated large T antigen is expressed, has rarely been investigated. Nonetheless, considering the strong oncogenic potential of MCPyV proteins in MCC, the plausible contribution of MCPyV to transformation and cancer growth in non-MCC tumors cannot be ruled out. Furthermore, the absence of MCPyV in cancers does not exclude a hit-and-run mechanism, or the oncoproteins of MCPyV may potentiate the neoplastic process mediated by co-infecting oncoviruses such as high-risk human papillomaviruses and Epstein-Barr virus. The current review is focusing on the available data describing the presence of MCPyV in non-MCC tumors, with an aim to provide a comprehensive overview of the corresponding literature and to discuss the potential contribution of MCPyV to non-MCC cancer in light of this.

Danger is only skin deep: aggressive epidermal carcinomas. An overview of the diagnosis, demographics, molecular-genetics, staging, prognostic biomarkers, and therapeutic advances in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a high grade primary cutaneous neuroendocrine carcinoma and is among the most aggressive cutaneous malignancies. The rising incidence of MCC, together with its often rapidly aggressive course, underscore a critical need to recognize the histopathologic and the immunohistochemical features that inform its accurate diagnosis. In the current review, we summarize the current state of knowledge regarding the accurate diagnosis of MCC and the exclusion of other entities in the differential diagnosis. We provide a comprehensive review of genomic studies that identified the molecular-genetic drivers of MCC as well as a summary of studies identifying prognostic biomarkers that can facilitate risk stratification. Importantly, Merkel cell polyomavirus (MCPyV) appears to be causative in most cases of MCC and represents both a diagnostic and prognostic marker. Finally, as staging of MCC has undergone critical refinements with the introduction of the 8th Edition of the American Joint Committee on Cancer staging system, we provide an update on MCC staging. In particular, the prognostic significance of the sentinel lymph node (SLN) in MCC necessitates a systematic approach to its evaluation and diagnosis to ensure accurate and consistent risk stratification for patients, and we therefore provide a comprehensive overview of SLN evaluation in MCC. Finally, the intimate relationship between MCC and the integrity of the host immune system has led to paradigm-shifting therapeutic advances with the successful application of immune checkpoint blockade to treat patients with advanced disease, and we therefore summarize those studies and the correlative studies in which predictive biomarkers have been identified.

A pilot study of alternative TrkAIII splicing in Merkel cell carcinoma: a potential oncogenic mechanism and novel therapeutic target

BACKGROUND

Merkel cell carcinomas (MCCs) are rare, aggressive, therapeutically-challenging skin tumours that are increasing in incidence and have poor survival rates. The majority are caused by genomic Merkel cell polyomavirus (MCPyV) integration and MCPyV T-antigen expression. Recently, a potential oncogenic role for the tropomyosin-related tyrosine kinase A receptor (TrkA) has been proposed in MCC. Alternative TrkAIII splicing is a TrkA oncogenic activation mechanism that can be promoted by SV40 large T-antigen, an analogue of MCPyV large T-antigen. In this pilot study, therefore, we have evaluated TrkAIII splicing as a novel potential oncogenic mechanism and therapeutic target in MCPyV positive MCC.

METHODS

Formalin-fixed paraffin-embedded MCC tissues, consisting of 10 stage IV, 1 stage IIIB, 1 stage IIB, 4 stage IIA and 2 stage I tumours, from patients diagnosed and treated from September 2006 to March, 2019, at the University of L'Aquila, L'Aquila, Italy, were compared to 3 primary basal cell carcinomas (BCCs), 3 primary squamous cell carcinomas (SCCs) and 2 normal skin samples by RT-PCR for MCPyV large T-antigen, small T-antigen, VP-1 expression and alternative TrkAIII splicing and by indirect IF for evidence of intracellular TrkA isoform expression and activation.

RESULTS

9 of 10 Recurrent stage IV MCCs were from patients (P.1-3) treated with surgery plus loco-regional Melphalan chemotherapy and remaining MMCs, including 1 stage IV tumour, were from patients treated with surgery alone (P. 4-11). All MCPyV positive MCCs exhibiting MCPyV large T-antigen expression (17 of 18MCCs, 90%) exhibited alternative TrkAIII mRNA splicing (100%), which was exclusive in a significant number and predominant (> 50%) in all stage IV MCCs and the majority of stage 1-III MCCs. MCCs with higher TrkAIII to 18S rRNA expression ratios also exhibited strong or intermediate immunoreactivity to anti-TrkA antibodies, consistent with cytoplasmic TrkAIII expression and activation. In contrast, the MCPyV negative MCC, BCCs, SCCs and normal skin tissues all exhibited exclusive fully-spliced TrkA mRNA expression, associated with variable immunoreactivity for non-phosphorylated but not phosphorylated TrkA.

CONCLUSIONS

MCPyV positive MCCs but not MCPyV negative MCC, BCCs and SCCs exhibit predominant alternative TrkAIII splicing, with evidence of intracellular TrkAIII activation. This establishes a new potential MCC subset, unveils a novel potential MCPyV oncogenic mechanism and identifies TrkAIII as a novel potential therapeutic target in MCPyV positive MCC.

Neurofilament is superior to cytokeratin 20 in supporting cutaneous origin for neuroendocrine carcinoma

AIM

Primary cutaneous neuroendocrine carcinoma, or Merkel cell carcinoma (MCC), cannot be distinguished morphologically from small-cell neuroendocrine carcinomas (SmCC) from other sites. Immunohistochemistry is required to confirm cutaneous origin, and is also used for detection of sentinel lymph node (SLN) metastases of MCC. Cytokeratin 20 (CK20) expression is commonly used for these purposes, but is negative in some MCC cases, and has unclear specificity. We evaluated immunohistochemistry for neurofilament and CK20 in MCC compared with SmCC from other sites.

METHODS AND RESULTS

We evaluated neurofilament expression in 55 MCC specimens from 39 unique patients, including nine CK20-negative MCC tumours. Neurofilament expression was observed in 42 of 55 (76.4%) MCC cases, including seven of nine (77.8%) CK20-negative MCC cases. Neurofilament was expressed in nine of 12 (75%) Merkel cell polyomavirus-positive tumours and five of 10 (50%) virus-negative tumours. Compared to a standard immunohistochemical panel (cytokeratin cocktail and CK20), neurofilament was 87.5% sensitive for detecting SLN metastases. Neurofilament and CK20 expression was also assessed in 61 extracutaneous SmCC from 60 unique patients, with primary sites including lung (27), bladder (18), cervix (3), gastrointestinal tract (3), sinonasal tract (2) and other sites (7). The specificity of neurofilament and CK20 for MCC versus non-cutaneous SmCC was 96.7% and 59.0%, respectively.

CONCLUSIONS

Neurofilament has superior specificity to CK20 in distinguishing MCC from non-cutaneous SmCC. Neurofilament is frequently expressed in CK20- and virus-negative MCC tumours. Limitations of neurofilament immunohistochemistry include lower sensitivity than CK20 and subtle staining in some tumours. However, our findings indicate that neurofilament is useful for excluding non-cutaneous SmCC.

Update on Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma. Incidence of MCC continues to rise, and risk factors include advanced age, pale skin, chronic sun exposure, and immune suppression. Diagnosing MCC utilizes a combination of morphology and immunohistochemistry. Merkel cell polyomavirus (MCPyV) is present in approximately 70-80% of MCCs and represents a key pathogenic driver in those MCCs. In contrast, MCPyV-negative MCCs arise through progressive accumulation of ultraviolet-light induced somatic mutations. Staging of MCC proceeds according to the American Joint Commission on Cancer (AJCC) 8th Edition, which utilizes features of the primary tumor together with regional lymph node(s) (clinically and/or pathologically detected) and/or distant metastases. Many potentially useful biomarkers have been studied to refine risk stratification in MCC. In recent years, the host immune infiltrate has been leveraged as immune checkpoint blockade has emerged as an efficacious mode of treatment for patients with advanced MCC.

Detection of Merkel Cell Polyomavirus in Seborrheic Keratosis

Seborrheic keratosis (SK) is the most common benign cutaneous neoplasm. A subset shows increased p16 expression. Since SK shares several features with verruca vulgaris, e.g., increased p16 expression, human papillomaviruses (HPV) have been suggested as possible causal agents. However, a relevant association could not be established between HPV and SK. In the present study we aimed to investigate the presence of Merkel cell polyomavirus (MCPyV) in relation to p16 expression in SK. P16 expression was investigated using immunohistochemistry (IHC). Presence of MCPyV was assessed in 23 formalin-fixed paraffin-embedded tissue samples of SK by molecular techniques (i.e., PCR and FISH) and IHC. 16/23 SK showed strong to moderate p16 expression. 6/23 of SK were MCPyV positive by PCR which was confirmed by FISH. Of interest, two samples with strong FISH signals also showed MCPyV expression as tested by IHC. Samples with weaker signal intensity were negative in IHC. P16 expression was not associated with the presence of MCPyV. Concluding, the detection of MCPyV DNA by PCR and FISH in SK reflects the widespread prevalence of MCPyV in the skin. However, low detection rates exclude MCPyV as a major pathogenic factor in SK, most likely representing a coincidental infection. P16 IHC does not appear as useful adjunctive surrogate marker for the presence of MCPyV in SK.

Merkel Cell Polyomavirus: A New DNA Virus Associated with Human Cancer

Merkel cell polyomavirus (MCPyV or MCV) is a novel human polyomavirus that has been discovered in Merkel cell carcinoma (MCC), a highly aggressive skin cancer. MCPyV infection is widespread in the general population. MCPyV-associated MCC is one of the most aggressive skin cancers, killing more patients than other well-known cancers such as cutaneous T-cell lymphoma and chronic myelogenous leukemia (CML). Currently, however, there is no effective drug for curing this cancer. The incidence of MCC has tripled over the past two decades. With the widespread infection of MCPyV and the increase in MCC diagnoses, it is critical to better understand the biology of MCPyV and its oncogenic potential. In this chapter, we summarize recent discoveries regarding MCPyV molecular virology, host cellular tropism, mechanisms of MCPyV oncoprotein-mediated oncogenesis, and current therapeutic strategies for MCPyV-associated MCC. We also present epidemiological evidence for MCPyV infection in HIV patients and links between MCPyV and non-MCC human cancers.

Prevalence of cutaneous viral infections in incident cutaneous squamous cell carcinoma detected among chronic lymphocytic leukemia and hematopoietic stem cell transplant patients

The role of cutaneous viral infections in the development of non-melanoma skin cancer (NMSC), including cutaneous squamous cell carcinoma (SCC), among chronic lymphocytic leukemia (CLL) and blood and marrow transplant (BMT) patients is not established. CLL (n = 977) and BMT (n = 3587) patients treated at the Moffitt Cancer Center were included in a retrospective cohort study. Human papillomavirus (HPV) and human polyomavirus (HPyV) DNA were examined in a subset of incident SCC tumors. Five-year cumulative incidence of NMSC was 1.42% in both BMT (n = 31 NMSCs) and CLL (n = 18 NMSCs) cohorts. Of the nine SCC tumors examined from each cohort, 22.2% and 33.3% were positive for viral DNA in the transplant (HPV 65, MCV) and CLL (HPV 38, HPV 15, HPyV6) cohort, respectively. Enhanced skin cancer screening of BMT/CLL patients should be conducted to better capture incident NMSCs and examine the role of viral infections in these tumors.

Update on Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous neuroendocrine malignancy. Merkel cell polyomavirus, a tumorigenic DNA virus, is present in most MCC tumors, with implications for tumor biology, diagnosis, and management. Merkel cell polyomavirus-negative tumors have a high burden of UV-signature mutations, similar to melanoma. The histopathologic diagnosis of MCC requires immunohistochemistry to exclude morphologically similar entities. Therapies for advanced disease are currently lacking. Here, the features of MCC are reviewed, including recent molecular discoveries with implications for improved therapy for advanced disease.

Age and Gender Associations of Virus Positivity in Merkel Cell Carcinoma Characterized Using a Novel RNA In Situ Hybridization Assay

Purpose: Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine tumor of the skin. Merkel cell polyomavirus (MCPyV) plays an oncogenic role in the majority of MCCs. Detection of MCPyV in MCCs has diagnostic utility and prognostic potential. We investigated whether RNAscope, an RNA in situ hybridization (ISH) assay for detection of RNA transcripts in tissues, is useful for MCPyV detection.Experimental Design: We applied an RNAscope probe targeting MCPyV T antigen transcripts on tissue microarrays (TMA) and whole-tissue sections encompassing 87 MCCs from 75 patients, 14 carcinomas of other types, and benign tissues. For comparison, qPCR was performed on 57 cases of MCC from 52 patients.Results: RNA-ISH demonstrated the presence of MCPyV in 37 of 75 cases (49.3%). Notably, tumors from younger patients (<73 years) had a significantly higher virus positivity than those from elderly patients (≥73 years; 64.9% vs. 34.2%, P = 0.011). Female patients had a higher positive rate of MCPyV than male patients (66.7% vs. 39.6%, P = 0.032). Data from both RNA-ISH and qPCR were available for 57 samples. Considering MCPyV qPCR as the gold standard for determining MCPyV status, RNAscope had 100% sensitivity and 100% specificity. There was a strong correlation between qPCR copy number and RNA-ISH product score (Spearman correlation coefficient R² = 0.932, P < 0.0001).Conclusions: RNA-ISH is comparably sensitive to qPCR for detection of MCPyV and allows for correlation with tissue morphology. This study also reveals a significant association between age, gender, and MCPyV positivity. Clin Cancer Res; 23(18); 5622-30. ©2017 AACR.

Phylogenetic and structural analysis of merkel cell polyomavirus VP1 in Brazilian samples

Our understanding of the phylogenetic and structural characteristics of the Merkel Cell Polyomavirus (MCPyV) is increasing but still scarce, especially in samples originating from South America. In order to investigate the properties of MCPyV circulating in the continent in more detail, MCPyV Viral Protein 1 (VP1) sequences from five basal cell carcinoma (BCC) and four saliva samples from Brazilian individuals were evaluated from the phylogenetic and structural standpoint, along with all complete MCPyV VP1 sequences available at Genbank database so far. The VP1 phylogenetic analysis confirmed the previously reported pattern of geographic distribution of MCPyV genotypes and the complexity of the South-American clade. The nine Brazilian samples were equally distributed in the South-American (3 saliva samples); North American/European (2 BCC and 1 saliva sample); and in the African clades (3 BCC). The classification of mutations according to the functional regions of VP1 protein revealed a differentiated pattern for South-American sequences, with higher number of mutations on the neutralizing epitope loops and lower on the region of C-terminus, responsible for capsid formation, when compared to other continents. In conclusion, the phylogenetic analysis showed that the distribution of Brazilian VP1 sequences agrees with the ethnic composition of the country, indicating that VP1 can be successfully used for MCPyV phylogenetic studies. Finally, the structural analysis suggests that some mutations could have impact on the protein folding, membrane binding or antibody escape, and therefore they should be further studied.

Merkel cell polyomavirus (MCV) T-antigen seroreactivity, MCV DNA in eyebrow hairs, and squamous cell carcinoma

Background

The role of Merkel cell polyomavirus (MCV) infection in the etiology of non-melanoma skin cancers, other than Merkel cell carcinoma, is unclear. Previously, we reported a significant association between seropositivity to MCV capsid antigen and MCV DNA-positive cutaneous squamous cell carcinoma (SCC). Here we present associations between SCC and seroreactivity to MCV T-antigen (T-Ag) oncoprotein, as well as MCV DNA detected in eyebrow hairs.

Findings

A clinic-based case–control study, including 171 SCC cases and 300 controls without skin cancer, was conducted at Moffitt Cancer Center in Tampa, Florida. Multiplex assays were used to measure serum antibodies against MCV small and large T-Ag and MCV DNA in both eyebrow hairs and SCC tumors (n = 144). Odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated using logistic regression to evaluate the associations between MCV and SCC. No significant association was observed between seroreactivity to MCV full-length large or small T-Ag and SCC, overall [OR_{large T-Ag} = 0.99 (0.48-2.08), OR_{small T-Ag} = 0.31 (0.06–1.62)] or when comparing tumor MCV DNA-positive cases to controls [OR_{large T-Ag} = 1.06 (0.38–2.93)]. Only presence of MCV DNA in eyebrow hairs was significantly associated with MCV DNA-positive SCC [OR = 4.05 (2.01–8.18)].

Conclusion

MCV infection is unlikely to play a direct role in SCC.

Early and late promoters of BK polyomavirus, Merkel cell polyomavirus, Trichodysplasia spinulosa-associated polyomavirus and human polyomavirus 12 are among the strongest of all known human polyomaviruses in 10 different cell lines

Recently, 11 new human polyomaviruses (HPyVs) have been isolated and named KI, WU, Merkel cell polyomavirus (MCPyV), HPyV6,  -7,  -9,  -10 and  -12, Trichodysplasia spinulosa-associated polyomavirus (TSPyV), STLPyV and NJPyV-2013. Little is known about cell tropism of the novel HPyVs, and cell cultures allowing virus propagation are lacking. Because viral tropism partially depends on the interaction of cellular transcription factors with the viral promoter, we monitored the promoter activity of all known HPyVs. Therefore, we compared the relative early and late promoter activity of the BK polyomavirus (BKPyV) (WW strain) with the corresponding activities of the other HPyVs in 10 different cell lines derived from brain, colon, kidney, liver, lung, the oral cavity and skin. Our results show that the BKPyV, MCPyV, TSPyV and HPyV12 early promoters displayed the strongest activity in most cell lines tested, while the remaining HPyV had relative low early promoter activity. HPyV12 showed the highest late promoter activity of all HPyVs in most cell lines, but also the BKPyV, MCPyV and TSPyV late promoters belonged to the stronger ones among HPyVs. The HPyVs with weak early promoter activity had in general also weak late promoter activity, except for HPyV10 whose late promoter was relatively strong in six of the 10 cell lines. A 20 bp deletion in the promoter of an HPyV12 variant significantly affected both early and late promoter activity in most cell lines. In conclusion, our findings suggest which cell lines may be suitable for virus propagation and may give an indication of the cell tropism of the HPyVs.

Natural history of polyomaviruses in men: the HPV infection in men (HIM) study

BACKGROUND

Several new polyomaviruses have been discovered in the last decade, including Merkel cell polyomavirus (MCPyV). Little is known about the natural history of the more recently discovered polyomaviruses. We estimated the incidence, prevalence, and persistence of 9 polyomaviruses (MCPyV, BK polyomavirus, KI polyomavirus, JC polyomavirus, WU polyomavirus, Human polyomavirus 6 [HPyV6], HPyV7, HPyV9, and Trichodysplasia spinulosa-associated polyomavirus) and examined factors associated with MCPyV infection in a prospective cohort of 209 men initially enrolled in the HPV Infection in Men (HIM) study.

METHODS

Participants enrolled at the US site of the HIM study were recruited into a substudy of cutaneous viral infections and followed for a median of 12.6 months. Eyebrow hair and normal skin swab specimens were obtained at each study visit, and the viral DNA load was measured using multiplex polymerase chain reaction.

RESULTS

MCPyV infection showed the highest prevalence (65.1% of normal skin swab specimens and 30.6% of eyebrow hair specimens), incidence (81.7 cases per 1000 person-months among normal skin swab specimens, and 24.1 cases per 1000 person-months among eyebrow hair specimens), and persistence (85.8% of normal skin swab specimens and 58.9% of eyebrow hair specimens) among all polyomaviruses examined. Age of >44 years (odds ratio [OR], 2.11; 95% confidence interval [CI], 1.03-4.33) and Hispanic race (OR, 2.64; 95% CI, 1.01-6.88) were associated with an increased prevalence of MCPyV infection in eyebrow hair and normal skin swab specimens, respectively.

CONCLUSION

MCPyV infection is highly prevalent in adults, with age and race being predisposing factors.

Association of Merkel cell polyomavirus infection with EGFR mutation status in Chinese non-small cell lung cancer patients

OBJECTIVES

Female lung cancer patients with no smoking habit and non-mucinous adenocarcinoma have a higher rate of epidermal growth factor receptor (EGFR) gene mutations, which is related to tyrosine kinase inhibitors (TKIs) sensitivity. Unfortunately the cause of EGFR gene mutations is still elusive. In this study, we search for the association between Merkel cell polyomavirus (MCPyV) infection and EGFR gene mutations.

MATERIALS AND METHODS

We studied 189 non-small cell lung cancer (NSCLC) samples for the presence of MCPyV large T (LT) DNA, LT antigen and EGFR hotspot mutations. Clinicopathological parameters of this cohort were also analyzed.

RESULTS

Thirty out of 163 adenocarcinoma and 2 out of 18 squamous cell carcinoma were found to have MCPyV LT DNA by PCR. Immunostaining also showed LT protein expression in most of the DNA positive samples. EGFR mutations were more frequently detected in female (P=0.009) and non-smoking patients (P=0.0001). Furthermore, a significant association between MCPyV infection and EGFR mutations was found (P=0.001).

CONCLUSION

Our study shows that MCPyV LT DNA is present in a subgroup of NSCLC, which is significantly correlated with EGFR mutations. To the best of our knowledge, this is the first study to find an association between MCPyV infection and EGFR hotspot mutations. These results support the possibility that MCPyV has a partial role in the carcinogenesis of NSCLC in a subgroup of patients.

Support for p63 expression as an adverse prognostic marker in Merkel cell carcinoma: report on a Canadian cohort

Recent evidence has invoked immunohistochemical expression of p63 in Merkel cell carcinoma as an adverse prognostic factor. Conflicting data led us to evaluate this. An Eastern Canadian cohort diagnosed between 1990 and 2012 was studied. Demographic and clinical data were obtained from pathology records and Provincial Cancer Registries. Pathological features were evaluated by the investigators. Merkel cell polyomavirus status was known in a subset of cases. Clinicopathological features were correlated with overall survival. The cohort consisted of 83 patients (mean age, 75.8 ± 11.7 years) with a male/female ratio of 1.24:1. In a mean follow-up period of 175 weeks (±177), 51 patients died (61.4%). Of several parameters examined, 6 showed significant adverse associations with survival on univariate analysis: age (hazard ratio [HR], 1.05 [1.02-1.08]), clinical stage (III/IV versus I/II; HR, 2.24 [1.18-4.27]), tumor size (HR, 1.16 [1.05-1.28]), combined versus pure morphology (HR, 1.82 [1.04-3.18]), minimal tumor-infiltrating lymphocytes (HR, 2.23 [1.04-4.78]), and expression of p63 (positive in 49.4%; HR, 1.93 [1.09-3.43]). In the stage I/II subgroup, p63 expression was associated with a trend toward poor survival. On multivariate analysis, p63 expression was not significantly associated with reduced survival. Our data support existing evidence that p63 expression in Merkel cell carcinoma carries adverse implications for survival. That it was not an independent prognostic factor may be due to study size and/or its potential as a confounding variable with clinical stage. Of clinical importance is its association with a trend toward a poor outcome in early stage disease.

Simulators of squamous cell carcinoma of the skin: diagnostic challenges on small biopsies and clinicopathological correlation

Squamous cell carcinoma (SCC) is a common and important primary cutaneous malignancy. On skin biopsies, SCC is characterized by significant squamous cell atypia, abnormal keratinization, and invasive features. Diagnostic challenges may occasionally arise, especially in the setting of small punch biopsies or superficial shave biopsies, where only part of the lesion may be assessable by the pathologist. Benign mimics of SCC include pseudoepitheliomatous hyperplasia, eccrine squamous syringometaplasia, inverted follicular keratosis, and keratoacanthoma, while malignant mimics of SCC include basal cell carcinoma, melanoma, and metastatic carcinoma. The careful application of time-honored diagnostic criteria, close clinicopathological correlation and a selective request for a further, deeper, or wider biopsy remain the most useful strategies to clinch the correct diagnosis. This review aims to present the key differential diagnoses of SCC, to discuss common diagnostic pitfalls, and to recommend ways to deal with diagnostically challenging cases.