Human Merkel cell polyomavirus: virological background and clinical implications

Is the presence of Merkel cell polyomavirus and human papillomavirus DNA in keratinocyte cancers and precancers associated with HIV status? A case-control study

The epidemiology and potential pathogenic roles of human papillomavirus (HPV) and Merkel cell polyomavirus (MCV) in keratinocyte cancers (KCs) arising in people living with HIV (PLWH) compared with HIV-negative individuals are poorly understood. These issues were investigated by a case-control study in which the presence of MCV and HPV DNA was identified by polymerase chain reaction in microdissected formalin-fixed paraffin-embedded tissue from PLWH and HIV-negative individuals. The samples comprised 190 cutaneous and genital KCs/precancers (actinic keratoses, n = 43; cutaneous squamous cell carcinoma (cSCC) in situ, n = 24; basal cell carcinoma, n = 78; cSCC, n = 34; penile carcinoma in situ, n = 9; penile SCC, n = 2 from 104 individuals (PLWH, n = 51; HIV-negative, n = 53). Almost one-quarter of samples were positive for MCV: this was not significantly associated with either HIV status (P = 0.06) nor lesion type. Overall, 36% (16/44) of MCV-positive lesions were coinfected with HPV; this was also not associated with HIV status. These findings indicate that if these viruses do contribute to the pathogenesis of KCs, it is likely to be independent of HIV status.

The prognostic role of PD-L1 expression and the presence of polyomavirus in Merkel cell carcinoma cases

BACKGROUND

Merkel cell carcinoma (MCC) comprises a rare malignant primary skin tumor presenting neuroendocrine differentiation. Recently, agents blocking the programmed cell death protein 1 and programmed cell death protein ligand 1 pathway (PD-1/PD-L1) have demonstrated objective and durable tumor regressions in patients presenting advanced MCC. This study aimed to describe the sociodemographic, clinical, and histopathological characteristics of MCC patients, also assessing the prevalence of PD-L1 expression and Merkel cell Polyomavirus (MCPyV), as well as their prognostic roles.

METHODS

Data from patients diagnosed with MCC between 1996 and 2019 at a reference cancer center in Rio de Janeiro, southeastern Brazil, were evaluated in a retrospective study. Tumor samples were tested for MCPyV and PD-L1 employing immunohistochemistry. Survival analyses were carried out employing the Kaplan-Meier method and curves were compared using the log-rank test. A multiple semiparametric Cox model was used. Values p < 0.05 were considered significant.

RESULTS

A total of 65 patients were included in the study, with a mean age at diagnosis of 72 (standard deviation 13.9). A total of 56.9% (37/65) of the patients were male, 86.2% (56/65) were white, and 56.9% (37/64) were illiterate or with incomplete elementary school. MCPyV immunohistochemistry was positive in 29 cases (44.6%) and PD-L1 positivity was ≥ 1% in 42 cases (64.6%). Significant associations between MCPyV and PD-L1 expression ≥ 1% (p = 0.003) and PD-L1 expression ≥ 5% (p = 0.005) were noted. Concerning the multivariate analysis, only education level and advanced MCC stage indicated statistically significant worse progression-free survival. Regarding overall survival (OS), being male, education level and advanced stage comprised risk factors. The estimated OS at 60 months for stages I to III was of 48.9% and for stage IV, 8.9%.

CONCLUSIONS

This is the first large Brazilian cohort to assess the prevalence of MCPyV in MCC tumors, as well as PD-L1 expression and their associations. No correlations were noted between MCPyV infection or PD-L1 expression and survival rates.

Metagenomic Analysis of DNA Viruses with Targeted Sequence Capture of Canine Lobular Orbital Adenomas and Normal Conjunctiva

Our study aims are: (1) to evaluate phenotypically normal canine conjunctival and orbital tissue and tissue from canine lobular orbital adenomas (CLOAs) for the presence of viral genomic material and (2) phylogenetically classify detected DNA viruses to determine if a DNA virus is associated with CLOAs. A total of 31 formalin fixed paraffin embedded CLOA tissue samples, 4 papillomas or sarcoid, and 10 fresh clinically normal conjunctival tissues were included in this study. Genomic DNA was isolated from all samples and sequencing libraries were prepared. The libraries were molecularly indexed and pooled and viral DNA was enriched via targeted sequence capture utilizing ViroCap. The libraries were sequenced on the Illumina HiSeq platform and compared to known viral DNA reference genomes to identify viral DNA. Carnivore parvovirus was identified in 6.4% and 20% of CLOA tissue and normal conjunctival samples, respectively. This study showed that conjunctival tissue from healthy dogs and CLOAs uncommonly harbor DNA viruses, and no DNA virus was associated with these tumors. Further studies are needed to evaluate the etiologic cause of CLOAs.

Immunological evidence of an early seroconversion to oncogenic Merkel cell polyomavirus in healthy children and young adults

Oncogenic Merkel cell polyomavirus (MCPyV) provokes a widespread and asymptomatic infection in humans. Herein, sera from healthy children and young adults (HC, n = 344) aged 0-20 years old were evaluated for anti-MCPyV immunoglobulin G (IgG) and IgM antibodies employing a recently developed immunoassay. Serum MCPyV IgG data from healthy subjects (HS, n = 510) and elderlies (ES, n = 226), aged 21-65/66-100 years old, from our previous studies, were included. The anti-MCPyV IgG and IgM rates in HC sera were 40.7% and 29.7%, respectively. A lower prevalence of anti-MCPyV IgGs was found in HC aged 0-5 years old (13%) compared to 6-10 (52.3%), 11-15 (60.5%) and 16-20 years old (61.6%) cohorts. Age-stratified HCs exhibited similar anti-MCPyV IgM rates (27.9%-32.9%). Serological profiles indicated that anti-MCPyV IgGs and IgMs had low optical densities (ODs) during the first years of life, while IgM ODs appeared to decrease throughout young adulthood. A lower anti-MCPyV IgGs rate was found in HC (40.7%) than HS (61.8%) and ES (63.7%). Upon the 5-years range age-stratification, a lower anti-MCPyV IgGs rate was found in the younger HC cohort aged 0-5 years old compared to the remaining older HC/HS/ES cohorts (52.3%-72%). The younger HC cohort exhibited the lowest anti-MCPyV IgG ODs than the older cohorts. Low anti-MCPyV IgMs rates and ODs were found in the 21-25 (17.5%) and 26-30 (7.7%) years old cohorts. Our data indicate that, upon an early-in-life seroconversion, the seropositivity for oncogenic MCPyV peaks in late childhood/young adulthood and remains at high prevalence and relatively stable throughout life.

Clinical-Pathological Evaluation and Prognostic Analysis of 228 Merkel Cell Carcinomas Focusing on Tumor-Infiltrating Lymphocytes, MCPYV Infection and ALK Expression

Merkel cell carcinoma is a rare and aggressive primary neuroendocrine carcinoma of the skin, whose pathogenesis can be traced back to UV radiation damage or Merkel cell polyomavirus (MCPyV) infection. Despite some improvements on the characterization of the disease partly due to its increased incidence, crucial pathogenetic and prognostic factors still need to be refined. A consecutive series of 228 MCC from three hospitals in Turin was collected with the aim of both analyzing the apparent increase in MCC incidence in our area and investigating the distribution and prognostic role of clinical-pathological parameters, with a focus on MCPyV status, ALK tumor expression and tumor infiltrating lymphocytes (TILs). Review of morphology and conventional immunohistochemical staining was possible in 191 cases. In 50 cases, the expression of the novel neuroendocrine marker INSM1 was additionally assessed. Fourteen cases of MCC of unknown primary skin lesion were identified and separately analyzed. While confirming an exponential trend in MCC incidence in the last decades and providing a description of histological and cytological features of a large series of MCC, the present study concludes that 1) INSM1 is a highly sensitive marker in both skin and lymph node primary MCC; 2) positive MCPyV status, brisk TILs and lower tumor size and thickness are independent positive prognostic parameters, and the combination of the former two may provide a novel tool for prognostic stratification; 3) ALK is expressed 87% of MCC and associated with positive viral status, and could represent a prognostic biomarker, if validated in larger series.

Virus-Like Particles as Preventive and Therapeutic Cancer Vaccines

Virus-like particles (VLPs) are self-assembled viral protein complexes that mimic the native virus structure without being infectious. VLPs, similarly to wild type viruses, are able to efficiently target and activate dendritic cells (DCs) triggering the B and T cell immunities. Therefore, VLPs hold great promise for the development of effective and affordable vaccines in infectious diseases and cancers. Vaccine formulations based on VLPs, compared to other nanoparticles, have the advantage of incorporating multiple antigens derived from different proteins. Moreover, such antigens can be functionalized by chemical modifications without affecting the structural conformation or the antigenicity. This review summarizes the current status of preventive and therapeutic VLP-based vaccines developed against human oncoviruses as well as cancers.

Significantly Low Levels of IgG Antibodies Against Oncogenic Merkel Cell Polyomavirus in Sera From Females Affected by Spontaneous Abortion

Merkel cell polyomavirus (MCPyV) is a small DNA tumor virus ubiquitous in humans. MCPyV establishes a clinically asymptomatic lifelong infection in healthy immunocompetent individuals. Viral infections are considered to be risk factors for spontaneous abortion (SA), which is the most common adverse complication of pregnancy. The role of MCPyV in SA remains undetermined. Herein, the impact of MCPyV infection in females affected by SA was investigated. Specifically, an indirect enzyme-linked immunosorbent assay (ELISA) method with two linear synthetic peptides/mimotopes mimicking MCPyV antigens was used to investigate immunoglobulin G (IgG) antibodies against MCPyV in sera from 94 females affected by SA [mean ± standard deviation (SD) age 35 ± (6) years] and from 96 healthy females undergoing voluntary pregnancy interruption [VI, mean (±SD) age 32 ± (7) years]. MCPyV seroprevalence and serological profiles were analyzed. The overall prevalence of serum IgG antibodies against MCPyV was 35.1% (33/94) and 37.5% (36/96) in SA and VI females, respectively (p > 0.05). Notably, serological profile analyses indicated lower optical densities (ODs) in females with SA compared to those undergoing VI (p < 0.05), thus indicating a reduced IgG antibody response in SA females. Circulating IgGs were identified in sera from SA and VI females. Our immunological findings indicate that a relatively reduced fraction of pregnant females carry serum anti-MCPyV IgG antibodies, while SA females presented a more pronounced decrease in IgG antibody response to MCPyV. Although yet to be determined, this immunological decrease might prompt an increase in MCPyV multiplication events in females experiencing abortive events. The role of MCPyV in SA, if present, remains to be determined.

Epigenetic Dysregulations in Merkel Cell Polyomavirus-Driven Merkel Cell Carcinoma

Merkel cell polyomavirus (MCPyV) is a small DNA virus with oncogenic potential. MCPyV is the causative agent of Merkel Cell Carcinoma (MCC), a rare but aggressive tumor of the skin. The role of epigenetic mechanisms, such as histone posttranslational modifications (HPTMs), DNA methylation, and microRNA (miRNA) regulation on MCPyV-driven MCC has recently been highlighted. In this review, we aim to describe and discuss the latest insights into HPTMs, DNA methylation, and miRNA regulation, as well as their regulative factors in the context of MCPyV-driven MCC, to provide an overview of current findings on how MCPyV is involved in the dysregulation of these epigenetic processes. The current state of the art is also described as far as potentially using epigenetic dysregulations and related factors as diagnostic and prognostic tools is concerned, in addition to targets for MCPyV-driven MCC therapy. Growing evidence suggests that the dysregulation of HPTMs, DNA methylation, and miRNA pathways plays a role in MCPyV-driven MCC etiopathogenesis, which, therefore, may potentially be clinically significant for this deadly tumor. A deeper understanding of these mechanisms and related factors may improve diagnosis, prognosis, and therapy for MCPyV-driven MCC.

Decreased IgG Antibody Response to Viral Protein Mimotopes of Oncogenic Merkel Cell Polyomavirus in Sera From Healthy Elderly Subjects

Merkel cell polyomavirus (MCPyV) is the main causative agent of Merkel cell carcinoma (MCC), a rare but aggressive skin tumor with a typical presentation age >60 years. MCPyV is ubiquitous in humans. After an early-age primary infection, MCPyV establishes a clinically asymptomatic lifelong infection. In immunocompromised patients/individuals, including elders, MCC can arise following an increase in MCPyV replication events. Elders are prone to develop immunesenescence and therefore represent an important group to investigate. In addition, detailed information on MCPyV serology in elders has been debated. These findings cumulatively indicate the need for new research verifying the impact of MCPyV infection in elderly subjects (ES). Herein, sera from 226 ES, aged 66-100 years, were analyzed for anti-MCPyV IgGs with an indirect ELISA using peptides mimicking epitopes from the MCPyV capsid proteins VP1-2. Immunological data from sera belonging to a cohort of healthy subjects (HS) (n = 548) aged 18-65 years, reported in our previous study, were also included for comparisons. Age-/gender-specific seroprevalence and serological profiles were investigated. MCPyV seroprevalence in ES was 63.7% (144/226). Age-specific MCPyV seroprevalence resulted as 62.5% (25/40), 71.7% (33/46), 64.9% (37/57), 63.8% (30/47), and 52.8% (19/36) in ES aged 66-70, 71-75, 76-80, 81-85, and 86-100 years, respectively (p > 0.05). MCPyV seroprevalence was 67% (71/106) and 61% (73/120) in ES males and females, respectively (p > 0.05). Lack of age-/gender-related variations in terms of MCPyV serological profiles was found in ES (p > 0.05). Notably, serological profile analyses indicated lower optical densities (ODs) in ES compared with HS (p < 0.05), while lower ODs were also determined in ES males compared with HS males (p < 0.05). Our data cumulatively suggest that oncogenic MCPyV circulates in elders asymptomatically at a relatively high prevalence, while immunesenescence might be responsible for a decreased IgG antibody response to MCPyV, thereby potentially leading to an increase in MCPyV replication levels. In the worse scenario, alongside other factors, MCPyV might drive MCC carcinogenesis, as described in elders with over 60 years of age.

Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare and extremely aggressive neuroendocrine carcinoma of the skin, with increasing incidence worldwide. This review intends to propose a comprehensive evaluation of MCC epidemiology, clinical features, pathogenetic mechanisms, diagnosis, and therapies. A section is dedicated to immunological aspects and another to the involvement of angiogenesis and angiogenic growth factors in MCC progression, proposing novel diagnostic and therapeutic approaches. Advanced MCC tumors have been treated with immune checkpoint inhibitors with effective results. Therefore, the state of art of this immunotherapy is also examined, reporting on the most recent clinical trials in the field. We conclude by underlining the achievements in the understanding of MCC pathology and indicating the present needs for effective diagnosis and therapeutic management of the disease.

Serum Antibodies Against the Oncogenic Merkel Cell Polyomavirus Detected by an Innovative Immunological Assay With Mimotopes in Healthy Subjects

Merkel cell polyomavirus (MCPyV), a small DNA tumor virus, has been detected in Merkel cell carcinoma (MCC) and in normal tissues. Since MCPyV infection occurs in both MCC-affected patients and healthy subjects (HS), innovative immunoassays for detecting antibodies (abs) against MCPyV are required. Herein, sera from HS were analyzed with a novel indirect ELISA using two synthetic peptides mimicking MCPyV capsid protein epitopes of VP1 and VP2. Synthetic peptides were designed to recognize IgGs against MCPyV VP mimotopes using a computer-assisted approach. The assay was set up evaluating its performance in detecting IgGs anti-MCPyV on MCPyV-positive (n=65) and -negative (n=67) control sera. Then, the ELISA was extended to sera (n=548) from HS aged 18-65 yrs old. Age-specific MCPyV-seroprevalence was investigated. Performance evaluation indicated that the assay showed 80% sensitivity, 91% specificity and 83.9% accuracy, with positive and negative predictive values of 94.3% and 71%, respectively. The ratio expected/obtained data agreement was 86%, with a Cohen's kappa of 0.72. Receiver-operating characteristic (ROC) curves analysis indicated that the areas under the curves (AUCs) for the two peptides were 0.82 and 0.74, respectively. Intra-/inter-run variations were below 9%. The overall prevalence of serum IgGs anti-MCPyV in HS was 62.9% (345/548). Age-specific MCPyV-seroprevalence was 63.1% (82/130), 56.7% (68/120), 64.5% (91/141), and 66.2% (104/157) in HS aged 18-30, 31-40, 41-50 and 51-65 yrs old, respectively (p>0.05). Performance evaluation suggests that our indirect ELISA is reliable in detecting IgGs anti-MCPyV. Our immunological data indicate that MCPyV infection occurs asymptomatically, at a relatively high prevalence, in humans.

Colorectal Carcinoma Affected Patients Are Significantly Poor Responders Against the Oncogenic JC Polyomavirus

Background

Many investigations reported the association between human tumors and JCPyV, a polyomavirus with oncogenic potential. The association has been supported by studies that found JCPyV footprints in CRC and gliomas of different types. Indeed, JCPyV footprints including its nucleic acids and Tag oncoprotein have been revealed in CRC tissues.

Methods

Herein, sera from colorectal carcinoma (CRC) affected patients and healthy individuals (HS), employed as control, were analysed for immunoglobulin G (IgG) antibodies against specific JCPyV viral capsid protein 1 (VP1) antigens. The investigation was carried out employing an innovative immunological assay. Indeed, an indirect enzyme-linked immunosorbent assay (ELISA) with JCPyV VP1 mimotopes was used. JCPyV VP1 mimotopes consisted of synthetic peptides mimicking VP1 epitopes.

Results

Sera from CRC affected patients, evaluated using indirect ELISAs with synthetic mimotopes, showed a significant lower prevalence of IgG antibodies against JCPyV VP1 mimotopes (26%) compared to HS (51%), p<0.005. These data were confirmed by another method, the hemagglutination inhibition (HAI) assay. Altogether these results, i.e. the prevalence of serum IgG antibodies against JCPyV VP1 mimotopes from patients with CRC is approximately 50% lower than in HS, are of interest.

Discussion

Our data suggest that patients with CRC are significantly poor responders against JCPyV VP1 antigens. It is possible that CRC patients are affected by a specific immunological deregulation. This immunological dysfunction, revelled in CRC patients, may account for their predisposition to the colorectal carcinoma onset.

Merkel Cell Carcinoma: New Trends

Simple Summary

In this review, we discuss a rare skin cancer that occurs mostly in elderly people called “Merkel cell carcinoma” (MCC). The incidence is increasing due to ageing of the population, increased sun exposure, and the use of medication that inhibits the immune system. Unlike most other skin cancers, MCC grows rapidly and forms metastases easily. We discuss the biology and treatment of MCC. Management should be by an experienced and multidisciplinary team, and treatment must start quickly. The standard practice of MCC treatment is surgery followed by radiotherapy. However, because it concerns an elderly and often frail population, (extensive) surgery may not always be feasible due to the associated morbidity. In those situations, radiotherapy alone is a good alternative. An important new development is immunotherapy that can cause long-lasting responses in a significant proportion of the patients with recurrent or metastatic MCC.

Abstract

Merkel cell carcinoma (MCC) is a rare neuroendocrine tumor of the skin mainly seen in the elderly. Its incidence is rising due to ageing of the population, increased sun exposure, and the use of immunosuppressive medication. Additionally, with the availability of specific immunohistochemical markers, MCC is easier to recognize. Typically, these tumors are rapidly progressive and behave aggressively, emphasizing the need for early detection and prompt diagnostic work-up and start of treatment. In this review, the tumor biology and immunology, current diagnostic and treatment modalities, as well as new and combined therapies for MCC, are discussed. MCC is a very immunogenic tumor which offers good prospects for immunotherapy. Given its rarity, the aggressiveness, and the frail patient population it concerns, MCC should be managed in close collaboration with an experienced multidisciplinary team.

Structural Analysis of Merkel Cell Polyomavirus (MCPyV) Viral Capsid Protein 1 (VP1) in HIV-1 Infected Individuals

Merkel cell polyomavirus (MCPyV) viral protein 1 (VP1) is the capsid protein that mediates virus attachment to host cell receptors and is the major immune target. Given the limited data on MCPyV VP1 mutations, the VP1 genetic variability was examined in 100 plasma and 100 urine samples from 100 HIV+ individuals. Sequencing of VP1 DNA in 17 urine and 17 plasma specimens, simultaneously MCPyV DNA positive, revealed that 27 samples displayed sequences identical to VP1 of MCC350 strain. VP1 from two urine specimens had either Thr47Ser or Ile115Phe substitution, whereas VP1 of one plasma contained Asp69Val and Ser251Phe substitutions plus deletion (∆) of Tyr79. VP1 DNA in the remaining samples had mutations encoding truncated protein. Three-dimensional prediction models revealed that Asp69Val, Ser251Phe, and Ile115Phe caused neutral effects while Thr47Ser and Tyr79∆ produced a deleterious effect reducing VP1 stability. A549 cells infected with urine or plasma samples containing full-length VP1 variants with substitutions, sustained viral DNA replication and VP1 expression. Moreover, medium harvested from these cells was able to infect new A549 cells. In cells infected by samples with truncated VP1, MCPyV replication was hampered. In conclusion, MCPyV strains with unique mutations in the VP1 gene are circulating in HIV+ patients. These strains display altered replication efficiency compared to the MCC350 prototype strain in A549 cells.

Merkel Cell Polyomavirus and Merkel Cell Carcinoma

Viruses are the cause of approximately 15% of all human cancers. Both RNA and DNA human tumor viruses have been identified, with Merkel cell polyomavirus being the most recent one to be linked to cancer. This virus is associated with about 80% of Merkel cell carcinomas, a rare, but aggressive cutaneous malignancy. Despite its name, the cells of origin of this tumor may not be Merkel cells. This review provides an update on the structure and life cycle, cell tropism and epidemiology of the virus and its oncogenic properties. Putative strategies to prevent viral infection or treat virus-positive Merkel cell carcinoma patients are discussed.

Polyomavirus-driven Merkel cell carcinoma: Prospects for therapeutic vaccine development

Great strides have been made in cancer immunotherapy including the breakthrough successes of anti-PD-(L)1 checkpoint inhibitors. In Merkel cell carcinoma (MCC), a rare and aggressive skin cancer, PD-(L)1 blockade is highly effective. Yet, ~50% of patients either do not respond to therapy or develop PD-(L)1 refractory disease and, thus, do not experience long-term benefit. For these patients, additional or combination therapies are needed to augment immune responses that target and eliminate cancer cells. Therapeutic vaccines targeting tumor-associated antigens, mutated self-antigens, or immunogenic viral oncoproteins are currently being developed to augment T-cell responses. Approximately 80% of MCC cases in the United States are driven by the ongoing expression of viral T-antigen (T-Ag) oncoproteins from genomically integrated Merkel cell polyomavirus (MCPyV). Since T-Ag elicits specific B- and T-cell immune responses in most persons with virus-positive MCC (VP-MCC), and ongoing T-Ag expression is required to drive VP-MCC cell proliferation, therapeutic vaccination with T-Ag is a rational potential component of immunotherapy. Failure of the endogenous T-cell response to clear VP-MCC (allowing clinically evident tumors to arise) implies that therapeutic vaccination will need to be potent anśd synergize with other mechanisms to enhance T-cell activity against tumor cells. Here, we review the relevant underlying biology of VP-MCC, potentially applicable therapeutic vaccine platforms, and antigen delivery formats. We also describe early successes in the field of therapeutic cancer vaccines and address several clinical scenarios in which VP-MCC patients could potentially benefit from a therapeutic vaccine.

Immune status and the efficacy of radiotherapy on overall survival for patients with localized Merkel cell carcinoma: An analysis of the National Cancer Database

BACKGROUND

Immunosuppressed (IS) patients with Merkel cell carcinoma (MCC) have worse outcomes compared to immunocompetent (IC) patients, and it is unclear if adjuvant radiotherapy (RT) is beneficial for these patients. We sought to determine the effect of immune status on adjuvant RT efficacy regarding overall survival (OS) for patients with localized MCC.

METHODS

This was an observational study of National Cancer Database (NCDB) identifying patients with stage I/II or III MCC with known immune status diagnosed from 2010 to 2014. The median follow-up time was 29 months. OS was described using Kaplan-Meier methods and compared for subgroups by immune status and adjuvant RT using log-rank tests, multivariable Cox regression and interaction effect testing.

RESULTS

A total of 2049 IC and 255 IS patients were included. Adjuvant RT was associated with decreased hazard of death for stage I/II MCC (HR 0.65, CI 0.54-0.78) adjusting for factors including immune status. Interaction effect testing did not demonstrate a significant difference in the effect of adjuvant RT on OS between IC and IS status in either stage I/II or III MCC (both P values > 0.05).

CONCLUSIONS

In this observational study, adjuvant RT was associated with decreased hazard of death for patients with stage I/II MCC regardless of immune status. Adjuvant RT should be considered for both IS and IC patients with localized MCC.

Tumor Ulceration, Reduced Infiltration of CD8-Lymphocytes, High Neutrophil-to-CD8-Lymphocyte Ratio and Absence of MC Virus are Negative Prognostic Markers for Patients with Merkel Cell Carcinoma

(1) Background: Merkel cell carcinoma (MCC) is caused by the Merkel cell polyomavirus and UV radiation. Understanding of the underlying biology is limited, but identification of prognostic markers may lead to better prognostic stratification for the patients. (2) Methods: Ninety patients diagnosed with MCC (1996–2012) were included. Virus status was estimated by polymerase chain reaction (qPCR) and immunohistochemistry (IHC). Ulceration status, PD-L1, cd66b neutrophils, cd8 lymphocytes and biomarkers of vascularization (cd34 endothelial cells) and migration (e-cadherin) were estimated by IHC and analyzed with digital pathology. (3) Results: Virus was present in 47% of patient samples and correlated with lower E-cadherin expression (p = 0.0005), lower neutrophil-to-CD8 lymphocyte ratio (N:CD8 ratio) (p = 0.02) and increased PD-L1 expression (p = 0.03). Ulceration was associated with absence of virus (p = 0.03), increased neutrophil infiltration (p < 0.0001) and reduced CD8 lymphocyte infiltration (p = 0.04). In multivariate analysis, presence of virus (p = 0.01), ulceration (p = 0.05) and increased CD8 lymphocyte infiltration (p = 0.001) showed independent prognostic impacts on MCC-specific survival. (3) Conclusions: In this study, we found that a high N:CD8 ratio, ulceration, virus-negative status and absence of CD8 lymphocytes are negative prognostic markers. Accurate prognostic stratification of the patients may be important in the clinical setting for determination of adjuvant treatment.

Immune status and the efficacy of adjuvant radiotherapy for patients with localized Merkel cell carcinoma of the head and neck

PURPOSE

Immunosuppressed (IS) patients are at increased risk for developing Merkel cell carcinoma (MCC) with worsened outcomes compared to immunocompetent (IC) patients. We sought to determine the effects of immune status on the efficacy of adjuvant RT regarding OS for patients with stage I, II or III (localized) MCC of the head and neck.

METHODS/PATIENTS

The National Cancer Database was queried for patients with resected, localized MCC of the head and neck with known immune status. Kaplan-Meier methods were used to describe OS. Log-rank tests, multivariable Cox regression models and interaction effect testing were used to compare OS by subgroup categorized by patient and treatment factors including immune status and adjuvant RT receipt.

RESULTS

A total of 892 (89.6%) IC and 104 (10.4%) IS patients with MCC of the head and neck were included. Adjuvant RT was associated with improved 3-year OS rate for both IS patients (49.4% vs. 35.5%, p = 0.0467) and stage I/II IC patients (72.4% vs. 62.9%, p = 0.0092). Adjuvant RT was associated with decreased hazard of death (HR 0.77, 95% CI 0.62-0.95). Interaction effect testing did not demonstrate a difference in the efficacy of adjuvant RT on OS between IC and IS status (p = 0.157).

CONCLUSIONS

In this NCDB analysis, adjuvant RT was associated with decreased hazard of death for patients with localized MCC of the head and neck regardless of immune status and should be considered for both IS and IC patients.

The biology and treatment of Merkel cell carcinoma: current understanding and research priorities

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer associated with advanced age and immunosuppression. Over the past decade, an association has been discovered between MCC and either integration of the Merkel cell polyomavirus, which likely drives tumorigenesis, or somatic mutations owing to ultraviolet-induced DNA damage. Both virus-positive and virus-negative MCCs are immunogenic, and inhibition of the programmed cell death protein 1 (PD-1)–programmed cell death 1 ligand 1 (PD-L1) immune checkpoint has proved to be highly effective in treating patients with metastatic MCC; however, not all patients have a durable response to immunotherapy. Despite these rapid advances in the understanding and management of patients with MCC, many basic, translational and clinical research questions remain unanswered. In March 2018, an International Workshop on Merkel Cell Carcinoma Research was held at the US National Cancer Institute, at which academic, government and industry experts met to identify the highest-priority research questions. Here, we review the biology and treatment of MCC and report the consensus-based recommendations agreed upon during the workshop.

Merkel cell carcinoma (MCC) is a rare and aggressive form of nonmelanoma skin cancer. The availability of immune checkpoint inhibition has improved the outcomes of a subset of patients with MCC, although many unmet needs continue to exist. In this Consensus Statement, the authors summarize developments in our understanding of MCC while also providing consensus recommendations for future research.

Newly detected DNA viruses in juvenile nasopharyngeal angiofibroma (JNA) and oral and oropharyngeal squamous cell carcinoma (OSCC/OPSCC)

PURPOSE

Approximately 20% of cancers are estimated to have a viral etiology. We aimed to investigate whether DNA of 8 human parvoviruses [bocavirus 1-4 (HBoV1-4), parvovirus B19 (B19V), protoparvoviruses (bufa-, tusa-, and cutavirus)] and 13 human polyomaviruses (HPyV) can be detected in oropharyngeal and oral cavity squamous cell carcinoma (OPSCC/OSCC), and in juvenile nasopharyngeal angiofibroma (JNA) tissue samples.

METHODS

Fresh samples of seven JNA tissues and ten paired tissues of OSCC/OPSCC tumor and adjacent healthy tissues were collected. DNA extraction and real-time PCRs were performed to detect HBoV1-4, B19V, bufa- tusa- and cutavirus, and HPyV genomes.

RESULTS

JNA specimens were negative for all parvoviruses tested, whereas one JNA sample was Merkel cell polyomavirus (MCPyV) DNA positive. The OSCC/OPSCC samples were negative for the human protoparvoviruses, HBoV1-4, and all human polyomaviruses, except for one patient that was MCPyV DNA positive in both healthy and tumor tissues. Seven OSCC/OPSCC patients were positive for B19V DNA, three of them in both healthy and cancerous tissues and three in only healthy tissues. Three of the B19V DNA-positive patients harbored viral genotype 1, three genotype 2, and one genotype 3B.

CONCLUSIONS

These are the first reports of MCPyV and B19V DNA being detected in JNA and OPSCC. The significance of viral DNA positivity is unclear. B19V DNA is known to remain in the tissues lifelong, however, it is of interest that there are some patients with B19 DNA in healthy tissue, but not in the corresponding cancer tissue.

Merkel Cell Polyoma Viral Load and Intratumoral CD8+ Lymphocyte Infiltration Predict Overall Survival in Patients With Merkel Cell Carcinoma

Introduction: Merkel cell carcinoma (MCC) is linked to the presence of clonally integrated Merkel cell polyomavirus (MCPyV) in up to 80% of the cases. The aim of the study was to determine the prognostic value of baseline MCPyV viral load and lymphocytic infiltration.

Methods: MCPyV DNA prevalence, integration status and viral load were determined by specific quantitative real-time PCR in surgical specimens obtained from 49 patients with MCC treated with (n = 22, 45%) or without postoperative radiotherapy (RT). CD8+ tumor infiltrating lymphocytes (TILs) and programmed death ligand 1 (PD-L1) status were assessed using immunohistochemistry. MCPyV characteristics and immune marker expression were correlated with clinicopathological factors and overall survival (OS).

Results: Median age at diagnosis was 74 (range, 42–100); 51% of the patients were female. One-, three, and five-year OS rates were 83.8, 58.6, and 47.1%, respectively. A positive MCPyV status was associated with female gender (p = 0.042). Tumor localization (head/arms vs. trunk) positively correlated with PD-L1 status (p = 0.011) and combined CD8/PD-L1 expression (p = 0.038). Overall CD8+ infiltration was inversely associated with N-stage (p = 0.048). Stromal TILs correlated significantly with both PD-L1 expression (p = 0.010) and N-stage (p = 0.037). A high viral load (>median) was significantly associated with worse OS (p = 0.029) and high intratumoral CD8+ infiltration with improved OS for the entire cohort (p = 0.045).

Conclusion: These data provide important insight on the role of MCPy DNA viral load and TILs in the context of PD-L1 in patients with Merkel cell carcinoma. Future clinical studies should aim to explore the effect of PD-1/PD-L1 immune-checkpoint inhibitors in combination with existing radiotherapy approaches.

MicroRNAs as Potential Biomarkers in Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare and aggressive type of skin cancer associated with a poor prognosis. This carcinoma was named after its presumed cell of origin, the Merkel cell, which is a mechanoreceptor cell located in the basal epidermal layer of the skin. Merkel cell polyomavirus seems to be the major causal factor for MCC because approximately 80% of all MCCs are positive for viral DNAs. UV exposure is the predominant etiological factor for virus-negative MCCs. Intracellular microRNA analysis between virus-positive and virus-negative MCC cell lines and tumor samples have identified differentially expressed microRNAs. Comparative microRNA profiling has also been performed between MCCs and other non-MCC tumors, but not between normal Merkel cells and malignant Merkel cells. Finally, Merkel cell polyomavirus encodes one microRNA, but its expression in virus-positive MCCs is low, or non-detectable or absent, jeopardizing its biological relevance in tumorigenesis. Here, we review the results of microRNA studies in MCCs and discuss the potential application of microRNAs as biomarkers for the diagnosis, progression and prognosis, and treatment of MCC.

Effect of Patient Immune Status on the Efficacy of Radiation Therapy and Recurrence-Free Survival Among 805 Patients With Merkel Cell Carcinoma

PURPOSE

Patients with Merkel cell carcinoma (MCC) with chronic immunosuppression (IS) have worse outcomes, but the mechanisms are not well understood. We hypothesized that these differences may be mediated in part by differential response to treatment, and we evaluated whether radiation therapy (RT) efficacy is altered among IS compared with immune-competent (IC) patients with MCC.

METHODS AND MATERIALS

Among 805 patients with MCC, recurrence-free survival (RFS) and patterns of first recurrence were compared between 89 IS and 716 IC patients with stage I to III MCC treated with curative intent. We used a Fine and Gray's competing risk multivariable analysis to estimate associations with RFS.

RESULTS

IS and IC patients with MCC had similar demographic and disease characteristics. Most (77% IC, 86% IS) were irradiated (median, 50.4 Gy IC, 50.3 Gy IS), although more IS patients were irradiated to the primary site (97% vs 81%). With a median follow-up of 54.4 months, IS patients had inferior RFS (2-year: 30% vs 57%; P < .0001) and higher rates of local recurrence as the first site of relapse (25% vs 12%; P = .0002). The association between RT and RFS differed by immune status (interaction P = .01). Although RT was associated with significantly improved RFS among IC patients (hazard ratio 0.56, 95% confidence interval 0.44-0.72), no difference in RFS was observed with RT among IS patients (hazard ratio 1.49, 95% confidence interval 0.70-3.17).

CONCLUSIONS

Radiation therapy efficacy at current standard RT doses for MCC is impaired among immunosuppressed patients with MCC. Although a strong link between durability of RT response and immune function does not appear to be evident in most cancers, our results may reflect an especially dynamic interaction between immune status and RT efficacy in MCC.

Serum IgG antibodies from healthy subjects up to 100 years old react to JC polyomavirus

JC polyomavirus (JCPyV) was identified in 1971 in the brain tissue of a patient (J.C.) affected by the progressive multifocal leukoencephalopathy (PML). JCPyV encodes for the oncoproteins large T antigen (Tag) and small t-antigen (tag). These oncoproteins are responsible of the cell transformation and tumorigenesis in experimental animals. JCPyV is ubiquitous in human populations. After the primary infection, which is usually asymptomatic, JCPyV remains lifelong in the host in a latent phase. Its reactivation may occur in heathy subjects and immunocompromised patients. Upon reactivation, JCPyV could reach (i) the CNS inducing the PML, (ii) the kidney of transplant patients causing the organ rejection. Association between JCPyV, which is a small DNA tumor virus, and gliomas and colorectal carcinomas has been published. In the present investigation, we report on a new indirect ELISA with two specific synthetic peptides mimicking JCPyV VP1 immunogenic epitopes to detect specific serum IgG antibodies against JCPyV. Serum samples of healthy subjects (n = 355) ranging 2-100 years old, were analyzed by this new indirect ELISA. The linear peptides VP1 K and VP1 N resemble the natural JCPyV VP1 capsidic epitopes constituting a docking site for serum antibodies. Data from this innovative immunologic assay indicate that the overall prevalence of JCPyV-VP1 antibodies in healthy subjects is at 39%. The innovative indirect ELISA with JCPyV VP1 mimotopes seems to be a useful method to detect specific IgG antibodies against this virus, without cross-reactivity with the closely related SV40 and BKPyV polyomaviruses.

Histologic Mimics of Basal Cell Carcinoma

CONTEXT

- Basal cell carcinoma (BCC) is the most common human malignant neoplasm and is a frequently encountered diagnosis in dermatopathology. Although BCC may be locally destructive, it rarely metastasizes. Many diagnostic entities display morphologic and immunophenotypic overlap with BCC, including nonneoplastic processes, such as follicular induction over dermatofibroma; benign follicular tumors, such as trichoblastoma, trichoepithelioma, or basaloid follicular hamartoma; and malignant tumors, such as sebaceous carcinoma or Merkel cell carcinoma. Thus, misdiagnosis has significant potential to result in overtreatment or undertreatment.

OBJECTIVE

- To review key features distinguishing BCC from histologic mimics, including current evidence regarding immunohistochemical markers useful for that distinction.

DATA SOURCES

- Review of pertinent literature on BCC immunohistochemistry and differential diagnosis.

CONCLUSIONS

- In most cases, BCC can be reliably diagnosed by histopathologic features. Immunohistochemistry may provide useful ancillary data in certain cases. Awareness of potential mimics is critical to avoid misdiagnosis and resulting inappropriate management.

Survey of KI, WU, MW, and STL Polyomavirus in Cancerous and Non-Cancerous Lung Tissues

BACKGROUND/AIMS

The pathogenesis of the human polyomavirus (PyV) KI, WU, MW, and STL has not been elucidated yet. Respiratory transmission is suggested, but the site of the replication, tissue, and cell tropism is not clarified. KIPyV and WUPyV DNA and/or antigen were detected in normal lung tissues previously by others. In fact, a KIPyV DNA sequence was found in lung cancer samples. Up to date, there is no publication about the DNA prevalence of MWPyV and STLPyV neither in normal nor in cancerous lung tissues. The aim of the present study was to examine the DNA prevalence of these polyomaviruses in cancerous and non-cancerous lung tissue samples, in order to study the possible site for viral replication and/or persistence, and the potential association of these viruses with lung carcinogenesis as well.

METHODS

100 cancerous and 47 non-cancerous, formalin-fixed paraffin-embedded lung tissue samples were studied for KIPyV, WUPyV, MWPyV, and STLPyV by real-time PCR.

RESULTS AND CONCLUSION

Neither of the viruses was found in samples from small-cell, non-small-cell (adenocarcinoma, squamous-cell carcinoma and large-cell neuroendocrine lung cancer), mixed-type and non-differentiated lung carcinoma, and non-cancerous lung tissues (from patients with pneumonia, emphysema and fibrosis).

Polyomavirus Replication and Smoking Are Independent Risk Factors for Bladder Cancer After Renal Transplantation

BACKGROUND

Solid organ transplant recipients are at increased risk for developing malignancies. Polyomaviruses (PV) have been historically associated with experimental tumor development and recently described in association with renourinary malignancies in transplant patients. The aim of this study was to investigate the relationship between PV replication and smoking, and the development of malignant neoplasms in kidney transplant recipients.

METHODS

A retrospective case-control study was conducted for PV replication in all kidney biopsies and urine cytologies performed between 1998 and 2014 from kidney transplant recipients at the University of Maryland Medical Center. Polyomavirus-positive patients (n = 943) were defined as having any of the following: a kidney biopsy with PV associated nephropathy, any urine cytology demonstrating "decoy" cells, and/or significant polyomavirus BK viremia. Polyomavirus-negative matched patients (n = 943) were defined as lacking any evidence of PV replication. The incidence of malignancy (excluding nonmelanoma skin tumors) was determined in these 1886 patients and correlated with demographic data and history of smoking.

RESULTS

There was a 7.9% incidence of malignant tumors after a mean posttransplant follow-up of 7.9 ± 5.4 years. Among all cancer subtypes, only bladder carcinoma was significantly associated with PV replication. By multivariate analysis, only PV replication and smoking independently increased the risk of bladder cancer, relative risk, 11.7 (P = 0.0013) and 5.6 (P = 0.0053), respectively.

CONCLUSIONS

The findings in the current study indicate that kidney transplant recipients with PV replication and smoking are at particular risk to develop bladder carcinomas and support the need for long-term cancer surveillance in these patients.

Merkel Cell Carcinoma of the Head and Neck: Recommendations for Diagnostics and Treatment

Background

Merkel cell carcinoma (MCC) is a rare, aggressive tumor that often occurs in the head and neck region. Because of these features, the classifications and diagnostic and treatment regimens are frequently modified. Especially in the anatomically complex head and neck region, it is crucial to be aware of the current recommendations for diagnostics and treatment of MCC to ensure appropriate treatment. This overview aims to summarize the currently available literature.

Methods

The authors reviewed the relevant literature and international guidelines for MCC from 2012 to 2017 with respect to epidemiology and prognosis, diagnostic procedures and imaging, surgery, radiation, systemic treatment, and aftercare. These results were compared with existing guidelines, some of them current, and recommendations were derived.

Results

Marked developments in imaging have resulted in an increased use of functional imaging. The surgical concepts have changed regarding safety margins and the use of sentinel node biopsies. In systemic treatment, a move from conventional agents toward immuno-oncology can be observed.

Conclusions

For staging, it is important to be as exact as possible using functional imaging (e.g., positron emission tomography/computed tomography scan), especially in the head and neck area with its complex lymph drainage. This often plays an especially important role in early stages of the tumor, when the resection margin can be reduced to preserve the organ. Aftercare also should include functional imaging. In an advanced, metastatic stage, immuno-oncology (PD-1, PD-L1, CTLA-4) is superior to the previous methods of systemic treatment.

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.

Multiplex detection in tonsillar tissue of all known human polyomaviruses

BACKGROUND

In the past few years, eleven new human viruses have joined the two previously known members JCPyV and BKPyV of the Polyomaviridae family, by virtue of molecular methods. Serology data suggest that infections with human polyomaviruses (HPyVs) occur since childhood and the viruses are widespread in the general population. However, the viral persistence sites and transmission routes are by and large unknown. Our previous studies demonstrated that the four new HPyVs - KIPyV, WUPyV, MCPyV and TSPyV - were present in the tonsils, and suggested lymphoid tissue as a persistent site of these emerging human viruses. We developed a Luminex-based multiplex assay for simultaneous detection of all 13 HPyVs known, and explored their occurrence in tonsillar tissues of children and adults mostly with tonsillitis or tonsillar hypertrophy.

METHODS

We set up and validated a new Luminex-based multiplex assay by using primer pairs and probes targeting the respective HPyV viral protein 1 (VP1) genes. With this assay we tested 78 tonsillar tissues for DNAs of 13 HPyVs.

RESULTS

The multiplex assay allowed for simultaneous detection of 13 HPyVs with high analytical sensitivity and specificity, with detection limits of 100-102 copies per microliter, and identified correctly all 13 target sequences with no cross reactions. HPyV DNA altogether was found in 14 (17.9%) of 78 tonsils. The most prevalent HPyVs were HPyV6 (7.7%), TSPyV (3.8%) and WUPyV (3.8%). Mixed infection of two HPyVs occurred in one sample.

CONCLUSIONS

The Luminex-based HPyV multiplex assay appears highly suitable for clinical diagnostic purposes and large-scale epidemiological studies. Additional evidence was acquired that the lymphoid system plays a role in HPyV infection and persistence. Thereby, shedding from this site during reactivation might take part in transmission of the newly found HPyVs.

Specific IgG Antibodies React to Mimotopes of BK Polyomavirus, a Small DNA Tumor Virus, in Healthy Adult Sera

BK polyomavirus (BKPyV) was isolated in 1971 from the urine of a kidney transplant patient. Soon after its identification, BKPyV was characterized as a kidney-tropic virus, which is responsible of a significant fraction of the rejection of transplant kidney in the host. Moreover, in experimental conditions, BKPyV is able to transform different types of animal and human cells and to induce tumors of different histotypes in experimental animals. BKPyV DNA sequences have been detected in healthy individuals and cancer patients using polymerase chain reaction/Shouthern blot hybridization methods. Serum antibodies against this polyomavirus were revealed using immunological techniques, which, however, cross-react with other polyomaviruses such as JC (JCPyV) and Simian Virus 40. These non-specific data indicate the need of novel immunological methods and new investigations to check in a specific manner, BKPyV spread in humans. To this aim, mimotopes from BKPyV structural capsid protein 1 (VP1) were employed for specific immunological reactions to IgG antibodies of human serum samples. An indirect enzyme-linked immunosorbent assay with synthetic peptides mimicking immunogenic epitopes of BKPyV VP1 was set up and employed to test sera of healthy adult subjects. Data from this innovative immunological assay indicate that serum antibodies against BKPyV VP1 mimotopes are detectable in healthy subjects ranging from 18 to 90 years old. The overall prevalence of serum samples that reacted to BKPyV VP1 mimotopes was 72%. The strong points from this investigation are the novelty of the immunological method, its simplicity of the approach, and the specificity of BKPyV antibody reaction to VP1 mimotopes.

Clinicopathological characteristics of head and neck Merkel cell carcinomas

BACKGROUND

There are still controversies about the therapeutic strategies and subsequent outcome in head and neck Merkel cell carcinoma.

METHODS

Clinicopathological data of 23 Merkel cell carcinomas, 93 cutaneous head and neck squamous cell carcinomas (HNSCCs), 126 malignant melanomas, and 91 primary parotid gland carcinomas were comprehensively analyzed. Merkel cell carcinomas were cytokeratin 20 (CK20)/neuron-specific enolase (NSE)/chromogranin A (CgA)/synaptophysin (Syn)/thyroid transcription factor-1 (TTF-1)/MIB1 immunostained.

RESULTS

All Merkel cell carcinomas underwent wide local excision. Parotidectomy/neck dissection was performed in 40%/33% cutaneous Merkel cell carcinoma and 100%/100% in parotid gland Merkel cell carcinoma. Five-year recurrence-free interval (RFI)/overall survival (OS) was significantly higher in malignant melanoma (81/80%) than in cutaneous Merkel cell carcinoma/HNSCC. Interestingly, 5-year RFI/OS was significantly higher in Merkel cell carcinoma (61%/79%) than in HNSCC (33%/65%; p < .0001) despite comparable TNM classifications and treatment regimens. There were neither differences of RFI/OS between parotid gland Merkel cell carcinoma and parotid gland carcinomas, nor in the immunohistochemical profile.

CONCLUSION

Five-year RFI/OS was significantly better in cutaneous Merkel cell carcinoma when compared with TNM classification matched HNSCC. Five-year RFI/OS was comparable in parotid gland Merkel cell carcinoma and other primary parotid gland malignancies. © 2016 Wiley Periodicals, Inc. Head Neck 39: 92-97, 2017.

No Evidence of Human Polyomavirus 9, WU and KI DNA in Kidney and Urinary Bladder Tumour Tissue Samples

BACKGROUND/AIMS

The oncogenic potential of human polyomaviruses (HPyVs) has been proposed, but so far only Merkel cell carcinoma polyomavirus seems to be associated with a human tumour. The role of BK polyomavirus (BKPyV) in human tumourigenesis remains controversial. BKPyV establishes persistent infection in the urinary tract, and renal and bladder neoplasms have been studied extensively, but conflicting prevalence data are reported. KI, WU and HPyV9 were detected in urine samples suggesting that these viruses may also infect the urinary tract, but their presence in urinary tract tumours has not been studied. The aim of this work was to examine the prevalence of KIPyV, WUPyV, HPyV9 and BKPyV by PCR in renal and bladder neoplasms.

METHODS

A total of 190 formalin-fixed paraffin-embedded renal neoplasms, bladder cancer and kidney biopsy samples were analysed for the presence of BKPyV, KIPyV, WUPyV and HPyV9 DNA by real-time and nested PCR.

RESULTS

Amplifiable DNA was extracted from all the samples, but none of the studied viruses were detected in benign renal neoplasia (0/23), malignant renal tumours (0/89) or bladder cancer (0/76).

CONCLUSION

Our study did not find any evidence that BKPyV, KIPyV, WUPyV or HPyV9 are associated with bladder and renal tumours.

Merkel cell carcinoma: Do you know your guidelines?

BACKGROUND

Merkel cell carcinoma (MCC) is a cutaneous neuroendocrine malignancy that exhibits clinically aggressive features and is associated with a poor prognosis. The incidence of MCC seems to be increasing for reasons unknown, and is estimated to be 0.32/100,000 in the United States.

METHODS

This article will review the current literature and National Comprehensive Cancer Network practice guidelines in the treatment of MCC.

RESULTS

Resection of MCC with negative margins remains the mainstay of therapy. Positive nodal disease should be treated with neck dissection and adjuvant radiotherapy. High-risk patients should undergo adjuvant radiotherapy, which improves oncologic outcomes. The role of chemotherapy is less clear and is currently reserved for advanced-stage MCC and palliative therapy.

CONCLUSION

The pathogenesis of MCC has recently been impacted with the discovery of the Merkel cell polyomavirus (MCPyV). Research to establish targeted and immunologic therapeutic options are ongoing.

Update on the biology and clinical management of Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine cutaneous malignancy, with a predilection for sun-exposed sites in elderly patients. Despite an incidence 30 times less than that of melanoma, its disease-specific mortality is three times higher. Management of MCC remains challenging because of a limited understanding of its molecular biology, lack of prospective clinical trials, and limitations associated with retrospective reviews of therapeutic options. With the recent discovery of an associated human polyomavirus, significant progress has been made in the understanding of the pathogenesis of this malignancy. With this progress, there has been increasing optimism regarding new tools in the therapeutic armamentarium to fight this deadly disease. Here we present an overview on MCC with an emphasis on the most recent biologic discoveries and the rationale for novel targeted and immunotherapies.

European perspective on human polyomavirus infection, replication and disease in solid organ transplantation

Human polyomaviruses (HPyVs) are a growing challenge in immunocompromised patients in view of the increasing number of now 12 HPyV species and their diverse disease potential. Currently, histological evidence of disease is available for BKPyV causing nephropathy and haemorrhagic cystitis, JCPyV causing progressive multifocal leukoencephalopathy and occasionally nephropathy, MCPyV causing Merkel cell carcinoma and TSPyV causing trichodysplasia spinulosa, the last two being proliferative skin diseases. Here, the current role of HPyV in solid organ transplantation (SOT) was reviewed and recommendations regarding screening, monitoring and intervention were made. Pre-transplant screening of SOT donor or recipient for serostatus or active replication is currently not recommended for any HPyV. Post-transplant, however, regular clinical search for skin lesions, including those associated with MCPyV or TSPyV, is recommended in all SOT recipients. Also, regular screening for BKPyV replication (e.g. by plasma viral load) is recommended in kidney transplant recipients. For SOT patients with probable or proven HPyV disease, reducing immunosuppression should be considered to permit regaining of immune control. Antivirals would be desirable for treating proven HPyV disease, but are solely considered as adjunct local treatment of trichodysplasia spinulosa, whereas surgical resection and chemotherapy are key in Merkel cell carcinoma. Overall, the quality of the clinical evidence and the strength of most recommendations are presently limited, but are expected to improve in the coming years.

Polyomaviruses and disease: is there more to know than viremia and viruria?

Purpose of review

Polyomavirus nephropathy (PVN) mainly caused by BK virus (BKV) remains the most common productive viral infection of the kidney. Over the past decade, clinical interest often focused on BK viremia and viruria as the diagnostic mainstays of patient management. The purpose of this review is to discuss viral nephropathy in the context of BK viremia and viruria and new strategies to optimize diagnostic accuracy and patient management. The emerging roles of polyomaviruses in oncogenesis, salivary gland disease, and post-bone marrow transplantation as well as novel Polyomavirus strains are highlighted.

Recent findings

Areas of investigation include proposals by the Banff working group on the classification of PVN and studies on PVN progression and resolution, including the role cellular immune responses may play during reconstitution injury. New noninvasive strategies to optimize the diagnosis of PVN, that is, the urinary ‘polyomavirus-haufen’ test and mRNA expression levels for BKV in the urine, hold great promise to accurately identify patients with viral nephropathy. Tools are now available to separate ‘presumptive’ from ‘definitive’ disease in various patient cohorts including individuals post-bone marrow transplantation. Recent observations also point to a currently underrecognized role of polyomaviruses in oncogenesis post-transplantation and salivary gland disease in patients with HIV-AIDS.

Summary

This review summarizes recent studies on PVN and the significance of the BKV strain in disease. Current paradigms for patient management post-(renal) transplantation are discussed in the setting of new observations. Issues that still require clarification and further validation are highlighted.

Merkel cell carcinoma of the head and neck: pathogenesis, current and emerging treatment options

Merkel cell carcinoma (MCC) is a relatively uncommon, neuroendocrine, cutaneous malignancy that often exhibits clinically aggressive features and is associated with a poor prognosis. It typically presents as a painless, rapidly enlarging, dome-shaped red or purplish nodule in a sun-exposed area of the head and neck or upper extremities. Our understanding of MCC has increased dramatically over the last several years and the pathogenesis continues to be an area of active research. The etiology is likely multifactorial with immunosuppression, UV-induced skin damage, and viral factors contributing to the development of MCC. The recent discovery of Merkel cell polyomavirus has allowed for at least one aspect of disease development to be much better understood. In most cases, treatment consists of wide local excision with adjuvant radiation therapy. The role of chemotherapeutics is still being defined. The recent advancement of knowledge regarding the pathogenesis of MCC has led to an explosion research into novel therapeutic agents and strategies. This review seeks to summarize the current body of literature regarding the pathogenesis of MCC and potential targets for future therapies.

Human BK Polyomavirus-The Potential for Head and Neck Malignancy and Disease

Members of the human Polyomaviridae family are ubiquitous and pathogenic among immune-compromised individuals. While only Merkel cell polyomavirus (MCPyV) has conclusively been linked to human cancer, all members of the polyomavirus (PyV) family encode the oncoprotein T antigen and may be potentially carcinogenic. Studies focusing on PyV pathogenesis in humans have become more abundant as the number of PyV family members and the list of associated diseases has expanded. BK polyomavirus (BKPyV) in particular has emerged as a new opportunistic pathogen among HIV positive individuals, carrying harmful implications. Increasing evidence links BKPyV to HIV-associated salivary gland disease (HIVSGD). HIVSGD is associated with elevated risk of lymphoma formation and its prevalence has increased among HIV/AIDS patients. Determining the relationship between BKPyV, disease and tumorigenesis among immunosuppressed individuals is necessary and will allow for expanding effective anti-viral treatment and prevention options in the future.

Cytokeratin 20-negative Merkel cell carcinoma is infrequently associated with the Merkel cell polyomavirus

Merkel cell carcinoma is a rare, highly aggressive cutaneous neuroendocrine carcinoma most commonly seen in sun-damaged skin. Histologically, the tumor consists of primitive round cells with fine chromatin and numerous mitoses. Immunohistochemical stains demonstrate expression of neuroendocrine markers. In addition, cytokeratin 20 (CK20) is expressed in ∼95% of cases. In 2008, Merkel cell carcinoma was shown to be associated with a virus now known as Merkel cell polyomavirus in ∼80% of cases. Prognostic and mechanistic differences between Merkel cell polyomavirus-positive and Merkel cell polyomavirus-negative Merkel cell carcinoma may exist. There has been the suggestion that CK20-negative Merkel cell carcinomas less frequently harbor Merkel cell polyomavirus, but a systematic investigation for Merkel cell polyomavirus incidence in CK20-negative Merkel cell carcinoma has not been done. To test the hypothesis that Merkel cell polyomavirus is less frequently associated with CK20-negative Merkel cell carcinoma, we investigated 13 CK20-negative Merkel cell carcinomas from the files of the Cleveland Clinic and the University of Michigan for the virus. The presence or absence of Merkel cell polyomavirus was determined by quantitative PCR performed for Large T and small T antigens, with sequencing of PCR products to confirm the presence of Merkel cell polyomavirus. Ten of these (77%) were negative for Merkel cell polyomavirus and three (23%) were positive for Merkel cell polyomavirus. Merkel cell polyomavirus is less common in CK20-negative Merkel cell carcinoma. Larger series and clinical follow-up may help to determine whether CK20-negative Merkel cell carcinoma is mechanistically and prognostically unique.

Mutational analysis of merkel cell carcinoma

Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine malignancy that is associated with a poor prognosis. The pathogenesis of MCC is not well understood, and despite a recent plethora of mutational analyses, we have yet to find a set of signature mutations implicated in the majority of cases. Mutations, including TP53, Retinoblastoma and PIK3CA, have been documented in subsets of patients. Other mechanisms are also likely at play, including infection with the Merkel cell polyomavirus in a subset of patients, dysregulated immune surveillance, epigenetic alterations, aberrant protein expression, posttranslational modifications and microRNAs. In this review, we summarize what is known about MCC genetic mutations and chromosomal abnormalities, and their clinical significance. We also examine aberrant protein function and microRNA expression, and discuss the therapeutic and prognostic implications of these findings. Multiple clinical trials designed to selectively target overexpressed oncogenes in MCC are currently underway, though most are still in early phases. As we accumulate more molecular data on MCC, we will be better able to understand its pathogenic mechanisms, develop libraries of targeted therapies, and define molecular prognostic signatures to enhance our clinicopathologic knowledge.

Skin cancer in organ transplant recipients: more than the immune system

Organ transplant recipients (OTRs) are at increased risk of developing nonmelanoma skin cancers. This has long been thought to be caused by immunosuppression and viral infection. However, skin cancer risk among individuals with AIDS or iatrogenic immunodeficiency does not approach the levels seen in OTRs, suggesting other factors play a critical role in oncogenesis. In clinical trials of OTRs, switching from calcineurin inhibitors to mammalian target of rapamycin inhibitors consistently led to a significant reduction in the risk of developing new skin cancers. New evidence suggests calcineurin inhibitors interfere with p53 signaling and nucleotide excision repair. These two pathways are associated with nonmelanoma skin cancer, and squamous cell carcinoma in particular. This finding may help explain the predominance of squamous cell carcinoma over basal cell carcinoma in this population. Mammalian target of rapamycin inhibitors do not appear to impact these pathways. Immunosuppression, viral infection, and impaired DNA repair and p53 signaling all interact in OTRs to create a phenotype of extreme risk for nonmelanoma skin cancer.