Polyomavirus Research Articles

Long-read sequencing reveals complex patterns of wraparound transcription in polyomaviruses.

Polyomaviruses (PyV) are ubiquitous pathogens that can cause devastating human diseases. Due to the small size of their genomes, PyV utilize complex patterns of RNA splicing to maximize their coding capacity. Despite the importance of PyV to human disease, their transcriptome architecture is poorly characterized. Here, we compare short- and long-read RNA sequencing data from eight human and non-human PyV. We provide a detailed transcriptome atlas for BK polyomavirus (BKPyV), an important human pathogen, and the prototype PyV, simian virus 40 (SV40). We identify pervasive wraparound transcription in PyV, wherein transcription runs through the polyA site and circles the genome multiple times. Comparative analyses identify novel, conserved transcripts that increase PyV coding capacity. One of these conserved transcripts encodes superT, a T antigen containing two RB-binding LxCxE motifs. We find that superT-encoding transcripts are abundant in PyV-associated human cancers. Together, we show that comparative transcriptomic approaches can greatly expand known transcript and coding capacity in one of the simplest and most well-studied viral families.

Clinical, FDG-PET and Molecular Markers of Immune Checkpoint Inhibitor Response in Patients with Advanced Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare, highly aggressive, neuroendocrine cancer of the skin, associated with immunosuppression, Merkel cell polyoma virus (MCPyV) infection and UV-carcinogenesis.Whilst impressive and durable responses to immune checkpoint inhibitors have revolutionised the treatment of advanced MCC.

Two Cases of BK Polyoma Virus Nephropathy in Patients with Isolated Heart Transplantation: Clinical Usefulness of Urinary Cytology

<h3>Introduction</h3> BK polyoma virus (BKpV) nephropathy (BKpVN) has been often reported in patients with kidney transplantation, whereas reports regarding BKpVN in patients with heart transplantation (HTx) is still sparse. <h3>Case Report</h3> We recently encountered two patients who developed BKpVN after HTx. Both patients (Case 1 and 2) coincidentally received HTx at the age of 56. A standard triple-drug regimen consisting of tacrolimus, mycophenolate mofetil (MMF), and a corticosteroid was started after surgery and the regimen was converted to everolimus (EVL) with reduced tacrolimus within 6 months after HTx because of donor transmitted atherosclerosis in both patients. Case 1 further underwent percutaneous coronary intervention 3.5 years after HTx. Despite renal-sparing immunosuppresion, values of creatinine begun to increase after HTx in both patients and they were diagnosed with BKpVN through high viral DNA copy number in the urine and blood. Regarding case 1, pathological analysis of kidney biopsy specimens disclosed interstitial infiltrate with lymphocytes associated with tubular injury which also lead to the diagnosis of BKpVN. Retrospectively, both patients were positive for decoy cell within 1 year after HTx therefore, these patients should have been recognized as high risk for BKpVN. After the diagnosis of BKpVN, immunosuppressive regimen of them was further changed to minimum dose of EVL (a trough concentration of 6-7 ng/ml) and MMF (500 mg daily) respectively under the guidance of myocardial biopsy and they have been uneventful for over a year after the diagnosis of BKpVN despite severe chronic kidney disease. <h3>Summary</h3> We presented two rare cases of BKpVN after HTx. In our institution, urinary cytology is regularly examined if there are decoy cells which we think are the sign of over immunosuppression. However, decoy cells detected by urinary cytology also suggest that there is subclinical BKpV infection. Urinary cytology, a noninvasive and cost-effective examination, should be routinely performed for the risk assessment of BKpVN even in HTx patients, since detecting decoy cell would be helpful for the early diagnosis of BKpVN.

The Oncogenic Effects, Pathways, and Target Molecules of JC Polyoma Virus T Antigen in Cancer Cells.

JC polyoma virus (JCPyV) is a ubiquitous polyoma virus that infects the individual to cause progressive multifocal leukoencephalopathy and malignancies. Here, we found that T-antigen knockdown suppressed proliferation, glycolysis, mitochondrial respiration, migration, and invasion, and induced apoptosis and G2 arrest. The reverse was true for T-antigen overexpression, with overexpression of Akt, survivin, retinoblastoma protein, β-catenin, β-transducin repeat-containing protein (TRCP), and inhibitor of growth (ING)1, and the underexpression of mammalian target of rapamycin (mTOR), phosphorylated (p)-mTOR, p-p38, Cyclin D1, p21, vascular endothelial growth factor (VEGF), ING2, and ING4 in hepatocellular and pancreatic cancer cells and tissues. In lens tumor cells, T antigen transcriptionally targeted viral carcinogenesis, microRNAs in cancer, focal adhesion, p53, VEGF, phosphoinositide 3 kinase-Akt, and Forkhead box O signaling pathways, fructose and mannose metabolism, ribosome biosynthesis, and choline and pyrimidine metabolism. At a metabolomics level, it targeted protein digestion and absorption, aminoacryl-tRNA biosynthesis, biosynthesis of amino acids, and the AMPK signal pathway. At a proteomic level, it targeted ribosome biogenesis in eukaryotes, citrate cycle, carbon metabolism, protein digestion and absorption, aminoacryl-tRNA biosynthesis, extracellular-matrix-receptor interaction, and biosynthesis of amino acids. In lens tumor cells, T antigen might interact with various keratins, ribosomal proteins, apolipoproteins, G proteins, ubiquitin-related proteins, RPL19, β-catenin, β-TRCP, p53, and CCAAT-enhancer-binding proteins in lens tumor cells. T antigen induced a more aggressive phenotype in mouse and human cancer cells due to oncogene activation, inactivation of tumor suppressors, and disruption of metabolism, cell adhesion, and long noncoding RNA-microRNA-target axes.

Refractory bladder haemorrhage managed with cystoscopic diathermy in a patient with Ataxia-Telangiectasia and intercurrent BK polyomavirus infection

Ataxia telangiectasia (A-T) is a rare neurodegenerative immunodeficiency syndrome, characterised eponymously by progressive cerebellar ataxia and telangiectatic vessels, most often cutaneous. A-T displays autosomal recessive inheritance, is characterised by defective DNA repair due to mutations within the ATM gene on chromosome 11 [ 1 ]; and a lack of native ATM protein gives rise to the aforementioned hallmarks of the disease. With A-T comes a predisposition to haematological malignancy and humoral immunodeficiency, and as such these patients often suffer truncated lifespans [ 1 , 2 ]. Urological manifestations are rare, and intravesical involvement comprising bladder telangiectasia has only been described in a handful of cases, all of which have previously been treated with cyclophosphamide for malignancies, a known instigator of bladder haemorrhage [ [3] , [4] , [5] ]. Similarly, BK polyomavirus is a known precipitant of nephropathy and haemorrhagic cystitis in actively immunosuppressed renal transplant patients, though has not been established as such in genetically immunodeficient patients with native urological tissue [ 6 ]. Here we present, to our knowledge, the first case of refractory haemorrhagic cystitis in an A-T patient with intercurrent BK polyoma virus infection, who had previously been treated with cyclophosphamide for leukaemia, and propose that recurrent cystoscopic diathermy is a robust and relatively conservative surgical option to treat haemorrhagic cystitis secondary to bladder wall telangiectasia.

POS-800 OUTCOMES OF DECEASED DONOR KIDNEY TRANSPLANTATION AT CHO RAY HOSPITAL, VIETNAM

Cho Ray Hospital (CRH) started the kidney transplantation from deceased donor program with donor after brain death (DBD) in 2008, and with donor after circulatory death (DCD) in 2015. The aim of the study was to evaluate the outcomes of the deceased donor program of Cho ray Hospital, Ho Chi Minh City (HCMC), over 12 years. Case series study, both DBD and DCD kidney transplantation at CRH from 2008 to 2020. Of 30 donors, we had 25 DBD, 5 DCD, 24 males. Median age of donors was 39 Yo. 5 donors were extended criteria donor (ECD). 15 donors had Kidney Donor Profile Index < 80%. Causes of donor death included 5 strokes, 25 head traumas. 7 kidneys from 4 DBD were procured outside HCMC, the longest distance was 1712 km. We proceeded 55 kidney transplants (46 pts from DBD and 9 pts from DCD). 4 DBD recipients (DBDR) had second kidney transplant, 1 DCD recipient (DCDR) had dual kidney transplant from an ECD. Median waiting time were 45 months for DCDRs and 39 months for DBDRs (p=0.005). Median HLA mismatches was 4 antigens. Mean cold ischemic time of DCDRs was higher than that of DBDRs (no statistic significant). DCDRs had higher rate of delayed graft function (DGF) than that of DBDRs (77.9% vs 19.5%). Surgical complications were 4 hematomas, 2 ureteral stenosis, 1 symptomatic lymphocele, 1 renal artery thrombosis. Both DCD and DBD recipients had similar graft function at discharge time. Our deceased donor transplant had graft survival of 98.2%, and 84.7% at 1 year, and 5 years and patient survival of 92.7% and 89.5% at 1 year, and 5 years. Acute rejection in the first year and later were 6/55 cases (10.9%) and 5/55 cases (9.1%), respectively. DCDRs had lower graft and patient survival than DBDRs. 5 pts died with graft functioning. The most common infections occurred post-transplant were cytomegalovirus (CMV) infection (19 pts), and polyoma (BK) virus infection (8 pts). Median onset time of CMV and BK infection was 5 months, and 16 months, respectively. Tabled 1AllDCDDBDPNumber of recipients (n)55946Age at kidney Tx (median)3744360.461Male (n)398310.188WIT (min)(median)1213.550.001SWIT (min) (median)3837380.617CIT (h)(median)7.7115.20.065DGF (n)16880.000PNF (n)110Length of stays (days) (median)1227100.095Serum creatinine at discharge (mg%) (median)1.31.71.30.807Induction therapy (n)• Â · IL-2inhibitor397320.836• Â · Leukocyte depletion14212Maintenance immunosuppressive therapy (n)• Â · Tac+MMF/MPA+Pred498410.983• Â · Cyc+MMF/MPA+Pred615Biopsy-proven AR (n)7160.874• Â · ACR5050.300• Â · AMR2110.190Non-biopsy proven AR4130.628Graft survival• Â · At 1-year98.2%88.9%100%0.086• Â · At 5-year84.7%71.1%87.8%Pts survival• Â · At 1-year92.7%66.7%97.8%0.002• Â · At 5-year89.5%66.7%94.2%Death with graft functioning (n)5230.210Death total (n)9360.132Causes of death (n)• Â · Sudden cardiacdeath1010.150• Â · Aortic aneurysmrupture101• Â · Sepsis due tobacteria523• Â · PCP110• Â · SARS-COVI-2101Infection post-transplant (n)• Â · CMV196130.027• Â · BK virus8350.080• Â · PCP6240.234• Â · Pulmonary TB5230.134 Open table in a new tab Deceased donor kidney transplantation at CRH showed feasible outcomes and has increased the chance of kidney transplantation to patients on waiting list.

IKBKE phosphorylates and stabilizes Snail to promote breast cancer invasion and metastasis.

IKBKE, a non-canonical inflammatory kinase, is frequently amplified or activated, and plays predominantly oncogenic roles in human cancers, especially in breast cancer. However, the potential function and underlying mechanism of IKBKE contributing to breast cancer metastasis remain largely elusive. Here, we report that depletion of Ikbke markedly decreases polyoma virus middle T antigen (PyVMT)-induced mouse mammary tumorigenesis and subsequent lung metastasis. Biologically, ectopic expression of IKBKE accelerates, whereas depletion of IKBKE attenuates breast cancer invasiveness and migration in vitro and tumor metastasis in vivo. Mechanistically, IKBKE tightly controls the stability of transcriptional factor Snail in different layers, in particular by directly phosphorylating Snail, which markedly blocks the E3 ligase β-TRCP1-mediated Snail degradation, resulting in breast cancer epithelial-mesenchymal transition (EMT) and metastasis. These findings together reveal a novel oncogenic function of IKBKE in promoting breast cancer metastasis by governing Snail abundance, and highlight the potential of targeting IKBKE for metastatic breast cancer therapies.

Advances in Immunology: A Cornerstone in Diagnosis and Therapy of Merkel Cell Carcinoma.

Merkel cell cancer (MCC) is a rare cutaneous malignancy arising from neuroendocrine cells. This rare but lethal malignancy (mortality greater than 30%) has also tripled in incidence over the last two decades. The role of immunodeficiency in pathogenesis of this rare malignancy is well established, with elucidation of viral pathogenesis by Merkel cell polyoma virus (MCPyV), a novel polyoma virus, in a majority of patients. Viral neoantigens while playing an important role in oncogenesis can also aid in early immunologic detection of recurrent disease. Viral neoantigens can also be targets for immunotherapy. Immune checkpoint inhibitors (ICI) have established role in frontline therapy in addition to recurrence of metastatic MCC. ICI therapy is being explored in adjuvant and neoadjuvant settings as well. We would like to illustrate curative potential of early diagnosis of recurrence and prompt use of ICI in treatment of oligometastatic disease in our case presentation.

JC Polyoma Virus as a Possible Risk Factor for Prostate Cancer Development - Immunofluorescence and Molecular Based Case Control Study.

In vitro studies have produced conflicting results about the significance of the JC Polyoma Virus (JCV) in the human cancers. Our study aims to detect the presence of JCV Large T antigen (LTag) together with viral load quantitation in the prostate tumor samples to assess if JCV harbors risk factor for prostate cancer (PCa). This was a case control-based study. A total of 110 patients participated in this study, including 55 patients with PCa and another 55 patients with benign prostatic hyperplasia (BPH) as cases and controls, respectively. Tissue, blood and urine samples were collected from each participant. Tissues samples were analyzed for the presence of JCV Ltag using a direct immunofluorescence assay (IF). Only positive IF tested samples were subjected to viral quantitation assay. Data were collected and managed using SPSS version 20. The JCV LTag in the cases group was 23.63% (13/55) which was higher than that of the controls group 5.45% (3/55) with a P. value of .006 and O.R of 5.76. The mean of viral load was significantly higher among cases tissue specimens 20156 ± 5450 copies/ml compared to controls group 6378 ± 2456copies/ml with P-value of .002. The virus was detected in 11/13 (84.6%) urine samples of cases with a mean viral load of 14068 ± 4590 copies/ml compared to 2/3 (66.6%) of controls viral load 2534 ± 1267 copies/ml. In conclusion, a higher JCV LTag with more viral load were detected in cases group compared to controls. Our findings support a strong relationship between JCV infection and the probability of developing PCa.

NeuN, a DNA-binding neuron-specific protein expressed by Merkel cell carcinoma: analysis of 15 cases.

SummaryAimMerkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma, with an increasing worldwide incidence. It presents as a painless red to purple nodule on sun-exposed skin. MCC is presumed to arise from resident cutaneous Merkel cells. The pathogenesis of MCC is likely multifactorial with immunosuppression, UV-induced skin damage, and Merkel cell polyomavirus contributing to the development. The diagnosis of MCC relies upon characteristic morphologic features and use of immunohistochemical stains. Histologically, the differential diagnosis of Merkel cell carcinoma includes the ‘small round cell’ tumor group, particularly metastatic small cell carcinoma and hematological malignancies. This study investigates the expression of NeuN antibody, which recognizes the protein NeuN, normally present in most neuronal cell types and neuronal tumors, in Merkel cell carcinomas.Methods and resultsFifteen cases of Merkel cell carcinoma (7 men and 7 women; mean age 74 years) were retrieved from the institute database between the years 2011-2020. The immunohistochemical profile was investigated: CK20 (14/14), Neurofilament, (12/12), Synaptophysin (14/14); Chromogranin A (11/13), PAX5 (10/12), TDT (5/12), CK7 (1/14), TTF1 (0/14). Infection by Polyoma virus was detected in 11 of 14 patients. Most tumors showed middle/strong expression of NeuN. No cutaneous structures, or epidermal Merkel cells, showed expression of NeuN. The expression of NeuN was investigated in 17 primary small cell lung carcinomas: 2 cases were positive for Neu-N.ConclusionsAwareness of the staining pattern of Neu-N could aid in diagnosis of Merkel cell carcinoma, avoiding misinterpretation and erroneous diagnosis with other tumors.

Native BK virus nephropathy in lung transplant: a case report and literature review.

ABSTRACTClassically described in renal allografts, BK virus nephropathy is increasingly recognized in native kidneys of other non-renal solid organ transplants. We discuss a 68-year-old woman with a history of bilateral lung transplant referred for worsening renal function, confirmed to have BK virus nephropathy by biopsy with a serum BK virus polymerase chain reaction of over 59 million copies/mL. She was managed with a reduction in immunosuppression and intravenous cidofovir with no improvement in her clinical parameters. The seven prior reported cases of polyoma virus nephropathy in lung transplant recipients are reviewed, and the challenges of screening and management are discussed.

Merkel cell carcinoma: an updated overview of clinico-pathological aspects, molecular genetics and therapy.

Merkel cell carcinoma (MCC) is a rare cutaneous neuroendocrine carcinoma of uncertain origin. MCC incidence varies by country and has been increasing among white populations over the last three decades. MCC occurs most commonly in elderly men and typically arises on sun-exposed areas. It is associated with a high mortality rate due to rapid growth and significant metastatic potential. Clinical and histopathological diagnosis are challenging, but prompt recognition of the disease is imperative for a correct management. Several hypotheses have been proposed to define the cell of origin, which still remains controversial. The discovery of Merkel cell polyoma virus, identified in the majority of MCCs, led to the hypothesis of the existence of two tumour subtypes showing biological, clinico-pathological and prognostic differences. Significant interest is nowadays directed to characterize MCC genomic alterations and microRNA (miRNA) expression profiles. Current treatment strategies for MCC depend on staging, and typically consist of surgery, radiation therapy, chemotherapy and/or, more recently, immunotherapy. The aim of this review is to provide an updated overview of MCC with a special focus on clinico-pathological aspects, molecular-genetics and therapy.

Off-the-Shelf Third-Party Virus-Specific T Cell Therapy to Treat JC Polyomavirus Infection in Hematopoietic Stem Cell Transplantation Recipients

Progressive multifocal leukoencephalopathy (PML) is a progressive and generally fatal demyelinating neurologic disease that occurs in profoundly immunocompromised patients due to infection with the human polyomavirus JC virus (JCPyV). Treatment options are limited and are largely focused on restoring T cell immunity, and outcomes are historically poor. Control of JCPyV in the setting of an immunocompromised patient by adoptive transfer of third-party virus specific T cells (VSTs) has been described in a small number of cases. To investigate treatment response and outcomes in recipients of hematopoietic stem cell transplantation (HSCT) with PML treated with third-party VSTs directed against the BK virus, a highly homologous polyoma virus that shares immunogenic epitopes with JCPyV. A retrospective chart review was performed on 4 patients who received VSTs for the treatment of PML at Cincinnati Children's Hospital Medical Center since 2019. VSTs were administered safely, with no cases of graft-versus-host disease and no infusion reactions. One patient who was treated almost immediately after diagnosis was able to clear JCPyV from blood and cerebrospinal fluid, with resultant stabilization of neurologic decline. IFN-γ enzyme-linked immunospot (ELISpot) analysis demonstrated VSTs in the peripheral blood following infusion. Response was maintained through repeat infusions. Three other patients, all of whom had a longer delay between diagnosis and infusion, exhibited progressive neurologic decline despite varying degrees of improvement in viral load. PML is a rare but often fatal complication following HSCT for which few treatment options are available. BK-directed, JCPyV cross-reactive VSTs are a safe and viable therapeutic option, and prompt administration should be considered once PML is diagnosed. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

A 2-fold Approach to Polyoma Virus (BK) Nephropathy in Kidney Transplants: Distinguishing Direct Virus Effects From Cognate T Cell-mediated Inflammation.

BK nephropathy (BKN) in kidney transplants diagnosed by histology is challenging because it involves damage from both virus activity and cognate T cell-mediated inflammation, directed against alloantigens (rejection) or viral antigens. The present study of indication biopsies from the Integrated Diagnostic System in the International Collaborative Microarray Study Extension study measured major capsid viral protein 2 (VP2) mRNA to assess virus activity and a T cell-mediated rejection (TCMR) classifier to assess cognate T cell-mediated inflammation. Biopsies were assessed by local standard-of-care histology and by genome-wide microarrays and Molecular Microscope Diagnostic System (MMDx) algorithms to detect rejection and injury. In a subset of 102 biopsies (50 BKN and 52 BKN-negative biopsies with various abnormalities), we measured VP2 transcripts by real-time polymerase chain reaction. BKN was diagnosed in 55 of 1679 biopsies; 30 had cognate T cell-mediated activity assessed by by MMDx and TCMR lesions, but only 3 of 30 were histologically diagnosed as TCMR. We developed a BKN probability classifier that predicted histologic BKN (area under the curve = 0.82). Virus activity (VP2 expression) was highly selective for BKN (area under the curve = 0.94) and correlated with acute injury, atrophy-fibrosis, macrophage activation, and the BKN classifier, but not with the TCMR classifier. BKN with molecular TCMR had more tubulitis and inflammation than BKN without molecular TCMR. In 5 BKN cases with second biopsies, VP2 mRNA decreased in second biopsies, whereas in 4 of 5 TCMR classifiers, scores increased. Genes and pathways associated with BKN and VP2 mRNA were similar, reflecting injury, inflammation, and macrophage activation but none was selective for BKN. Risk-benefit decisions in BKN may be assisted by quantitative assessment of the 2 major pathologic processes, virus activity and cognate T cell-mediated inflammation.

Urinary extracellular vesicles: Assessment of pre-analytical variables and development of a quality control with focus on transcriptomic biomarker research.

Urinary extracellular vesicles (uEV) are a topical source of non‐invasive biomarkers for health and diseases of the urogenital system. However, several challenges have become evident in the standardization of uEV pipelines from collection of urine to biomarker analysis. Here, we studied the effect of pre‐analytical variables and developed means of quality control for uEV isolates to be used in transcriptomic biomarker research. We included urine samples from healthy controls and individuals with type 1 or type 2 diabetes and normo‐, micro‐ or macroalbuminuria and isolated uEV by ultracentrifugation. We studied the effect of storage temperature (‐20°C vs. ‐80°C), time (up to 4 years) and storage format (urine or isolated uEV) on quality of uEV by nanoparticle tracking analysis, electron microscopy, Western blotting and qPCR. Urinary EV RNA was compared in terms of quantity, quality, and by mRNA or miRNA sequencing. To study the stability of miRNA levels in samples isolated by different methods, we created and tested a list of miRNAs commonly enriched in uEV isolates. uEV and their transcriptome were preserved in urine or as isolated uEV even after long‐term storage at ‐80°C. However, storage at ‐20°C degraded particularly the GC‐rich part of the transcriptome and EV protein markers. Transcriptome was preserved in RNA samples extracted with and without DNAse, but read distributions still showed some differences in e.g. intergenic and intronic reads. MiRNAs commonly enriched in uEV isolates were stable and concordant between different EV isolation methods. Analysis of never frozen uEV helped to identify surface characteristics of particles by EM. In addition to uEV, qPCR assays demonstrated that uEV isolates commonly contained polyoma viruses. Based on our results, we present recommendations how to store and handle uEV isolates for transcriptomics studies that may help to expedite standardization of the EV biomarker field.

Atypical Urine Samples with Polyoma Virus Cytopathic Effect: Role of SV40 Immunostaining

Atypical Urine Samples with Polyoma Virus Cytopathic Effect: Role of SV40 Immunostaining

Elevated levels of Merkel cell polyoma virus in the anophthalmic conjunctiva

The human ocular surface hosts a paucibacterial resident microbiome and virome. The factors contributing to homeostasis of this mucosal community are presently unknown. To determine the impact of ocular enucleation and prosthesis placement on the ocular surface microbiome, we sampled conjunctival swabs from 20 anophthalmic and 20 fellow-eye intact conjunctiva. DNA was extracted and subjected to quantitative 16S rDNA PCR, biome representational karyotyping (BRiSK), and quantitative PCR (qPCR) confirmation of specific organisms. 16S ribosomal qPCR revealed equivalent bacterial loads between conditions. Biome representational in silico karyotyping (BRiSK) demonstrated comparable bacterial fauna between anophthalmic and intact conjunctiva. Both torque teno virus and Merkel cell polyoma virus (MCPyV) were detected frequently in healthy and anophthalmic conjunctiva. By qPCR, MCPyV was detected in 19/20 anophthalmic samples compared with 5/20 fellow eyes. MCPyV copy number averaged 891 copies/ng in anophthalmic conjunctiva compared with 193 copies/ng in fellow eyes (p < 0.001). These results suggest that enucleation and prosthesis placement affect the ocular surface flora, particularly for the resident virome. As MCPyV has been shown to be the etiologic cause of Merkel cell carcinoma, understanding the mechanisms by which the ocular surface regulates this virus may have clinical importance.

Merkel Cell Carcinoma of the Head and Neck: Epidemiology, Pathogenesis, Current State of Treatment and Future Directions.

Simple SummaryMerkel cell carcinoma of the head and neck is a relatively uncommon cutaneous malignancy with distinct treatment management from Merkel cell carcinoma occurring in other anatomic locations. The efficacy of immunotherapy has markedly changed prognosis for patients with locally advanced or metastatic Merkel cell carcinoma of the head and neck. However, patients with primary or acquired resistance to immunotherapy remain therapeutically challenging, with novel treatment being vital to improving outcomes. Given the novel therapeutic options available for these patients, as well as increasing characterization regarding the differing oncogenesis of Merkel cell polyoma virus-positive vs. -negative tumors, up to date information regarding epidemiology; oncogenesis; current standards of treatment; and future therapeutic avenues are important to improving outcomes for patients with Merkel cell carcinoma of the head and neck.Merkel cell carcinoma (MCC) is a rare, cutaneous neuroendocrine malignancy with increasing incidence. The skin of the head and neck is a common subsite for MCC with distinctions in management from other anatomic areas. Given the rapid pace of developments regarding MCC pathogenesis (Merkel cell polyoma virus (MCPyV)-positive or virus-negative, cell of origin), diagnosis, staging and treatment, and up to date recommendations are critical for optimizing outcomes. This review aims to summarize currently available literature for MCC of the head and neck. The authors reviewed current literature, including international guidelines regarding MCC pathogenesis, epidemiology, diagnosis, staging, and treatment. Subsequently recommendations were derived including the importance of baseline imaging, MCPyV serology testing, primary site surgery, nodal evaluation, radiotherapy, and the increasing role of immune modulating agents in MCC. MCPyV serology testing is increasingly important with potential distinctions in treatment response and surveillance between virus-positive and virus-negative MCC. Surgical management continues to balance optimizing local control with minimal morbidity. Similarly, radiotherapy continues to have importance in the adjuvant, definitive, and palliative setting for MCC of the head and neck. Immunotherapy has changed the paradigm for advanced MCC, with increasing work focusing on optimizing outcomes for non-responders and high-risk patients, including those with immunosuppression.

Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a rare neuroendocrine carcinoma. The cellular origin of MCC may include Merkel cell precursors. The incidence of MCC has increased significantly however trends may have been confounded by evolving diagnostic criteria. The two key aetiologies of MCC are ultraviolet radiation and Merkel cell polyoma virus (MCPyV). Both have unique mechanisms of carcinogenesis. MCC presents non‐specifically as a rapidly growing, red‐to‐violet nodule on sun‐exposed areas. Diagnostic accuracy has improved through immunohistochemical markers such as CK‐20. Lymph nodes should be evaluated in MCC through examination and sentinel biopsy. USS, CT, MRI and CT‐PET may be useful in staging. Management depends on tumour location, stage and comorbidities. MCPyV status may guide treatment strategy in the future. Treatment for the primary MCC is commonly wide local excision followed by radiotherapy, guided by anatomical constraints. There is uncertainty about surgical margins. Treatments for nodal disease have not been determined through trials. They include nodal dissection or radiotherapy for clinically or radiologically apparent disease, and adjuvant nodal irradiation for negative nodes, microscopic disease or following nodal dissection for definite disease. Patients with loco‐regional advanced inoperable disease should be considered for combination therapy including chemotherapy, radiotherapy, surgery and immunotherapy. Systemic therapy for advanced disease includes immune checkpoint inhibitors targeting the PD‐1/PD‐L1 pathway. Avelumab can improve survival in metastatic MCC. Immunotherapy may result in longer disease control. Various other immunotherapeutic and molecular agents are undergoing trials. MCC continues to have a high mortality characterized by high recurrence and early metastases.

Virus-Driven Carcinogenesis.

Simple SummaryCarcinogens, causes of cancer, are usually invisible and therefore in vivo carcinogenesis is difficult to detect. Tumor viruses, definitive carcinogens, are also usually unremarkable, particularly due to latent infection. However, recent developments in tumor virology are unraveling how a single infected cell becomes a life-threatening cell population from a molecular perspective. The recognition and characterization of virus-driven carcinogenesis is the first step in the eradication of tumor virus-associated cancer.Cancer arises from the accumulation of genetic and epigenetic alterations. Even in the era of precision oncology, carcinogens contributing to neoplastic process are still an important focus of research. Comprehensive genomic analyses have revealed various combinations of base substitutions, referred to as the mutational signatures, in cancer. Each mutational signature is believed to arise from specific DNA damage and repair processes, including carcinogens. However, as a type of carcinogen, tumor viruses increase the cancer risk by alternative mechanisms, including insertional mutagenesis, viral oncogenes, and immunosuppression. In this review, we summarize virus-driven carcinogenesis to provide a framework for the control of malignant cell proliferation. We first provide a brief overview of oncogenic viruses and describe their implication in virus-related tumors. Next, we describe tumor viruses (HPV, Human papilloma virus; HBV, Hepatitis B virus; HCV, Hepatitis C virus; EBV, Epstein–Barr virus; Kaposi sarcoma herpesvirus; MCV, Merkel cell polyoma virus; HTLV-1, Human T-cell lymphotropic virus, type-1) and tumor virus-related cancers. Lastly, we introduce emerging tumor virus candidates, human cytomegalovirus (CMV), human herpesvirus-6 (HHV-6) and adeno-associated virus-2 (AAV-2). We expect this review to be a hub in a complex network of data for virus-associated carcinogenesis.