title: Bovine papillomavirus load and mRNA expression, cell proliferation and p53 expression in four clinical types of equine sarcoid.
abstract: Equine sarcoids, the most common skin tumours in horses, are induced by bovine papillomavirus (BPV). Their clinical appearance varies from small stable patches to aggressively growing masses. Differences in BPV load and mRNA expression and Ki67 and p53 immunostaining among four clinical types (fibroblastic, occult, nodular and verrucous sarcoids) were evaluated to test the hypothesis that the clinical behaviour of equine sarcoids correlates with BPV activity. Viral load and expression of the BPV E2, E5, E6 and E7 genes were determined using quantitative real-time PCR. The proliferative fraction (PF) of the tumours was determined by Ki67 immunostaining and expression of p53 was analysed by immunohistochemistry. Nodular sarcoids showed a significantly higher viral load than the other types. A significant overall difference among the four types was observed for E2, E5, E6 and E7 mRNA expression. Nodular sarcoids showed the highest expression level for each BPV gene examined, followed by verrucous, fibroblastic and occult tumours. Viral DNA and mRNA outcomes correlated with each other, indicating a similar transcription pattern in each type of sarcoid. The PF was significantly higher in the superficial layers of verrucous and fibroblastic sarcoids compared with occult and nodular types. No significant difference was observed for the PF in the deep layers and for p53 expression. These results clearly demonstrate the omnipresence and active transcription of BPV in equine sarcoids. However, the hypothesis that the clinical behaviour of an equine sarcoid can be explained on the basis of differences in BPV activity could not be demonstrated.
authors.affiliation: Ghent University, Faculty of Veterinary Medicine, Department of Surgery and Anaesthesiology of Domestic Animals, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Bogaert
authors.affiliation: Ghent University, Faculty of Veterinary Medicine, Department of Nutrition, Genetics and Ethology, Heidestraat 19, B-9820 Merelbeke, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Van Poucke
authors.affiliation: Ghent University, Faculty of Veterinary Medicine, Department of Surgery and Anaesthesiology of Domestic Animals, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: De Baere
authors.affiliation: Ghent University, Faculty of Veterinary Medicine, Department of Obstetrics, Reproduction and Herd Health, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Dewulf
authors.affiliation: Ghent University, Faculty of Veterinary Medicine, Department of Nutrition, Genetics and Ethology, Heidestraat 19, B-9820 Merelbeke, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Peelman
authors.affiliation: Ghent University, Faculty of Veterinary Medicine, Department of Pathology, Bacteriology and Avian Diseases, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Ducatelle
authors.affiliation: Ghent University, Faculty of Veterinary Medicine, Department of Surgery and Anaesthesiology of Domestic Animals, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Gasthuys
authors.affiliation: Ghent University, Faculty of Veterinary Medicine, Department of Surgery and Anaesthesiology of Domestic Animals, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Martens
mesh_terms: D000818:Animals; D052688:Bovine papillomavirus 1 / Q000235:genetics / Q000302:isolation & purification*; D004279:DNA, Viral / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D003937:Diagnosis, Differential; D006734:Horse Diseases / Q000175:diagnosis / Q000378:metabolism* / Q000821:virology*; D006736:Horses / Q000821:virology*; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis / Q000378:metabolism; D008297:Male; D009856:Oncogene Proteins, Viral / Q000235:genetics; D030361:Papillomavirus Infections / Q000175:diagnosis / Q000378:metabolism / Q000662:veterinary* / Q000821:virology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D012367:RNA, Viral / Q000032:analysis; D012867:Skin / Q000378:metabolism* / Q000821:virology*; D012878:Skin Neoplasms / Q000175:diagnosis / Q000378:metabolism / Q000662:veterinary* / Q000821:virology; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics
chemical_list: D004279:DNA, Viral; D004268:DNA-Binding Proteins; C051550:E2 protein, Bovine papillomavirus; D019394:Ki-67 Antigen; D009856:Oncogene Proteins, Viral; D012333:RNA, Messenger; D012367:RNA, Viral; D016159:Tumor Suppressor Protein p53; D014764:Viral Proteins; C054304:oncogene protein E5, Bovine papillomavirus type 1; C075621:oncogene protein E7, Bovine papillomavirus type 1; C059269:protein E6, Bovine papillomavirus