Polyomavirus InfectionsPolyomavirusBK VirusMerkel cell polyomavirusCarcinoma, Merkel CellTumor Virus InfectionsJC VirusAntigens, Polyomavirus TransformingCapsid ProteinsDNA, ViralAntigens, Viral, TumorMolecular Sequence DataCell LineBase SequenceMerkel CellsViral ProteinsReplication Protein ARNA, ViralMutationPlasmids