title: EcPV-2 is transcriptionally active in equine SCC but only rarely detectable in swabs and semen from healthy horses.
abstract: Squamous cell carcinomas (SCC) are malignant tumours arising from keratinocytes. In horses, there is increasing evidence for Equus caballus papillomavirus type 2 (EcPV-2) being causally involved in SCC development. However, only little is known regarding intralesional transcription of the virus, and sparse information on the incidence of EcPV-2 infection in healthy equids is available so far. Using RT-PCR, total mRNA from 8 EcPV-2 DNA-positive and 1 EcPV-2 negative SCC/SCC precursor lesions was screened for the presence of EcPV-2 E6 and E1 transcripts. Using PCR, we tested 193 sample specimens (30 ocular swabs, 94 genital swabs, 54 semen and 15 milk samples) from a total of 161 apparently healthy horses for the presence of EcPV-2 genes E7 and E6 or E2. Positive results were confirmed by repeating the PCR reactions, and by amplicon sequencing. E6 mRNA was detectable in 8/8 EcPV-2 DNA-positive lesions, whereas only 3/8 scored positive for E1 mRNA. EcPV-2 PCR scored positive for DNA from 1/30 ocular swabs, 4/94 genital swabs, 0/54 semen and 0/15 milk samples, thus resulting in an overall detection rate of 5/193, i.e. 2.6%. The demonstrated presence of viral mRNA in all EcPV-2 DNA-positive lesions is suggestive for an active pathogenic role of the virus in SCC development. This finding and the low incidence of EcPV-2 DNA in healthy equids further strengthen the concept of an aetiologic association of EcPV-2 with equine SCC disease.
authors.affiliation: Large Animal Surgery and Orthopaedics, Equine Clinic, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria.
authors.forename: Sabine
authors.initials: S
authors.lastname: Sykora
authors.forename: Lisa
authors.initials: L
authors.lastname: Samek
authors.forename: Katharina
authors.initials: K
authors.lastname: Schönthaler
authors.forename: Franziska
authors.initials: F
authors.lastname: Palm
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Borzacchiello
authors.forename: Christine
authors.initials: C
authors.lastname: Aurich
authors.forename: Sabine
authors.initials: S
authors.lastname: Brandt
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology / Q000821:virology*; D005134:Eye Neoplasms / Q000662:veterinary / Q000821:virology; D006734:Horse Diseases / Q000473:pathology / Q000821:virology*; D006736:Horses / Q000821:virology*; D009856:Oncogene Proteins, Viral / Q000235:genetics; D027383:Papillomaviridae / Q000235:genetics*; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012661:Semen / Q000821:virology; D014158:Transcription, Genetic; D014565:Urogenital Neoplasms / Q000662:veterinary / Q000821:virology
chemical_list: D009856:Oncogene Proteins, Viral; D012367:RNA, Viral