Felis catus papillomavirus type 2 infection and skin cancer in domestic cats : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Manawatū, New Zealand
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Date
2016
DOI
Open Access Location
Authors
Thomson, Neroli
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Volume Title
Publisher
Massey University
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Abstract
Felis catus papillomavirus type 2 (FcaPV-2) is a virus which commonly infects the skin of
domestic cats. While most infections are asymptomatic, there is growing evidence that FcaPV-2
may play a role in the development of a subset of feline cutaneous squamous cell carcinomas
(SCCs).
In the first part of this thesis, the natural history of FcaPV-2 infection was investigated with the
aim of determining when cats become infected with the virus. A real-time PCR assay was
developed to quantify FcaPV-2 DNA in feline skin swabs. This assay was then used to measure
the FcaPV-2 DNA load in serial samples from two populations of cats. Results from these studies
showed that most kittens are exposed to FcaPV-2 in the first few days of life. Additionally, the
primary source of exposure is likely to be direct contact with other cats in the household,
particularly their queen, as some of the queens appeared to be shedding large amounts of virus.
FcaPV-2 mRNA was also detected in some of the kittens, confirming that they had become
infected with FcaPV-2 soon after birth.
The aim of the second part of this thesis was to determine the quantity and transcriptional
activity of the FcaPV-2 DNA present in feline cutaneous SCCs in order to determine if the virus
was involved in cancer development or just present as an innocent bystander. Real-time PCR
assays were developed to measure FcaPV-2 gene expression in SCCs and the results clearly
distinguished two subsets of feline cutaneous SCCs. The majority of the SCCs had low copy
numbers of FcaPV-2 DNA and no FcaPV-2 gene expression, suggesting the virus was an incidental
finding. In contrast, around a third of the SCCs had detectable FcaPV-2 gene expression and high
copy numbers of FcaPV-2 DNA, similar to that found in the FcaPV-2-induced premalignant
lesions. There was also a significant association between FcaPV-2 gene expression and
alterations in a host cell cycle regulatory protein (p16). Taken together, these results strongly
suggest that FcaPV-2 played a role in the development of around a third of the feline cutaneous
SCCs.
The results from the studies reported in this thesis support a causative role of FcaPV-2 in a
proportion of feline cutaneous SCCs. However, as infection of cats is common and appears to
occur early in life, there may be little opportunity to prevent SCC development by preventing
FcaPV-2 infection.
Description
Keywords
Squamous cell carcinoma, Papillomaviruses, Cats, Diseases, Veterinary oncology, Research Subject Categories::VETERINARY MEDICINE::Pathology