A study of the cytology and karyotype of the canine transmissible venereal tumour.

Abstract

SUMMARY Transmissible venereal tumours from 19 dogs in the Nairobi area of Kenya were examined. Five were from dogs examined post-mortem. These tumours were readily transmitted by subcutaneous inoculation of fragments into unrelated dogs. The tumours were composed mainly of oval or polyhedral cells, with large oval nuclei and prominent central nucleoli. The number of cells in mitosis was high. Ultrastructural examination of the tumour cells revealed no distinctive features. No virus-like particles were found on examination of 10 tumours. The cells from 9 tumours were analysed and 43% had a karyotype number of 59. Of these chromosomes, 17 were metacentric and 42 acrocentric. It is suggested that this tumour may be a long established line of cells derived from a clone capable of a parasitic existence on the genitalia of the dog.