Monday, June 8, 2009

Detection of Merkel cell polyomavirus DNA in Merkel cell carcinomas.

Detection of Merkel cell polyomavirus DNA in Merkel cell carcinomas.

Br J Dermatol. 2009 May

Varga E, Kiss M, Szabó K, Kemény L.
Department of Dermatology and Allergology, University of Szeged, Korányi fasor 6, H-6720 Szeged, Hungary.


Background Merkel cell carcinoma (MCC) is a rare, aggressive tumour for which an increasing incidence has been reported. A new human polyomavirus, Merkel cell polyomavirus (MCV), was recently isolated from these tumours by applying digital transcriptome subtraction methodology. Objectives To detect the presence or absence of MCV in MCCs and other, randomly selected neoplasms. Methods Nine primary or recurrent MCCs from seven patients were examined; 29 other tumours (squamous cell, basal cell and basosquamous carcinomas and malignant melanomas) were examined for comparative purposes. Viral large T protein (LT1 and LT3), and viral capsid protein (VP1) were detected by primer-directed amplification, using a polymerase chain reaction (PCR)-based method, and the amplified PCR products were analysed by agarose gel electrophoresis and subsequent sequence analysis. Results The presence of viral T antigen and/or viral capsid DNA sequences was demonstrated in seven of the eight MCC lesions. None of the comparative samples contained MCV DNA. Conclusions Our findings strongly support the hypothesis that MCV infection may well be specific for MCC, and MCV may play a role in the pathogenesis of MCC.

WileyInterScience

Human Merkel cell polyomavirus infection I. MCV T antigen expression in Merkel cell carcinoma, lymphoid tissues and lymphoid tumors.

Human Merkel cell polyomavirus infection I. MCV T antigen expression in Merkel cell carcinoma, lymphoid tissues and lymphoid tumors.
Int J Cancer. 2009 Apr

Shuda M, Arora R, Kwun HJ, Feng H, Sarid R, Fernández-Figueras MT, Tolstov Y, Gjoerup O, Mansukhani MM, Swerdlow SH, Chaudhary PM, Kirkwood JM, Nalesnik MA, Kant JA, Weiss LM, Moore PS, Chang Y.
Molecular Virology Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA.


Merkel cell polyomavirus (MCV) is a recently discovered human virus closely related to African green monkey lymphotropic polyomavirus. MCV DNA is integrated in approximately 80% of Merkel cell carcinomas (MCC), a neuroendocrine skin cancer linked to lymphoid malignancies such as chronic lymphocytic leukemia (CLL). To assess MCV infection and its association with human diseases, we developed a monoclonal antibody that specifically recognizes endogenous and transfected MCV large T (LT) antigen. We show expression of MCV LT protein localized to nuclei of tumor cells from MCC having PCR quantified MCV genome at an average of 5.2 (range 0.8-14.3) T antigen DNA copies per cell. Expression of this putative viral oncoprotein in tumor cells provides the mechanistic underpinning supporting the notion that MCV causes a subset of MCC. In contrast, although 2.2% of 325 hematolymphoid malignancies surveyed also showed evidence for MCV infection by DNA PCR, none were positive at high viral copy numbers, and none of 173 lymphoid malignancies examined on tissue microarrays expressed MCV LT protein in tumor cells. As with some of the other human polyomaviruses, lymphocytes may serve as a tissue reservoir for MCV infection, but hematolymphoid malignancies associated with MCC are unlikely to be caused by MCV.


PubMed

Human Merkel cell polyomavirus infection II. MCV is a common human infection that can be detected by conformational capsid epitope immunoassays.

Human Merkel cell polyomavirus infection II. MCV is a common human infection that can be detected by conformational capsid epitope immunoassays.

Int J Cancer. 2009 Apr

Tolstov YL, Pastrana DV, Feng H, Becker JC, Jenkins FJ, Moschos S, Chang Y, Buck CB, Moore PS.
Molecular Virology Program, University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA.


Merkel cell polyomavirus (MCV) is a newly-discovered human tumor virus found in approximately 80% of Merkel cell carcinoma (MCC). The rate of MCV infection among persons without MCC is unknown. We developed a MCV virus-like particle (VLP) enzyme-linked immunoassay (EIA) that does not cross-react with human BK or murine polyomaviruses. Peptide mapping of the MCV VP1 gene and immunoblotting with denatured MCV VLP are less sensitive than the MCV EIA in detecting MCV antibodies suggesting antibody reactivity in this assay primarily targets conformational but not linear epitopes. Among MCC patients, all 21 (100%) patients tested with MCV-positive tumors had high serum MCV IgG but not high MCV IgM levels. Only 3 of 6 (50%) MCC patients with MCV-negative tumors were positive for MCV antibodies. Sera from most adults, including 107 of 166 (64%) blood donors, 63 of 100 (63%) commercial donors and 37 of 50 (74%) systemic lupus erythematosus patients, show evidence for prior MCV exposure. Age-specific MCV prevalence was determined by examining a cross-sectional distribution of 150 Langerhans cell histiocytosis (an unrelated neoplasm) patient sera. MCV prevalence increases from 50% among children age 15 years or younger to 80% among persons older than 50 years. We did not find evidence for vertical transmission among infants. Although past exposure to MCV is common among all adult groups, MCC patients have a markedly elevated MCV IgG response compared with control patients. Our study demonstrates that MCV is a widespread but previously unrecognized human infection.


Wiley InterScience