An appraisal of Canine Transmissible Venereal Tumour with emphasis on molecular biology and pathology

Abstract

Canine transmissible venereal tumour (CTVT) is a contagious tumour of dogs, transmitted via coitus or coital
behaviour which in some cases spreads by metastasis but primarily, CTVT appears as reddish soft nodules or papilla,
protruding from the surface of the penis, prepuce, vagina and vulva but sometimes appears in locations outside the
genitals. There was early evidence of CTVT more than 10,000 years ago and this disease has been reported in at least
90 countries across the continents of the world, especially in third world countries, where there are high numbers of
stray dogs. CTVT natural infection occurs only in dogs but this disease can be experimentally inoculated into other
species of the family, Canidae. Macroscopic lesions are mainly cauliflower-like, papillary or multilobulated which most
times immunologically regress but occasionally may progress to malignancy. Due to the uniqueness of this tumour in
its transmission, broad geographical, sex and breed distribution and because CTVT is the world’s oldest known
neoplasm, this disease has attracted great global research interest. Diagnostic techniques including clinical examination,
histopathology, cytology, immunohistochemistry, cytogenetic, computer tomographic imaging and molecular
diagnostic methods such as Polymerase chain reaction (PCR) have been invaluable in the diagnosis of CTVT. Therefore,
this review casts a searchlight on the aetiology, structure, epidemiology, disease status, transmission, pathogenesis,
molecular biology, macroscopic and microscopic pathology, immunology, diagnosis, prevention, treatment and control
of this unique tumour.