Comparison of apoptosis in canine transmissible veneral tumor (TVT) pre and post chemotraoy with vincristine sulphate

The canine transmissible veneral tumor (CTVT) is a prevalent tumor in canidae. It is transmitted by coitus, forming multiple neoplastic masses on the external genitalia of both sexes within the family canidae. CTVT have an aberrant karyotype and the origin of the neoplastic cells is undetermined but immunophenotyping suggests that the tumor has a histocytic origin. In this study 10 dogs with canine transmissible veneral tumor were selected and received vincristine sulphate (0.025 mg/kg/b.w) chemotrapy to induce apoptosis in neoplastic cells. Biopsy specimens were collected from tumors during the growth phase, before and again after chemotherapy from the same dogs. The specimens were fixed in 10% formalin and then prepared routinely for H&E and TUNEL assays. Histopathological study of tissue section of CTVT before chemotherapy revealed sheets of uniform neoplastic cells, round to oval in shape with defined cytoplasmic border. There were a few TUNEL positive cells and mitotic figures. In tumor specimens after chemotherapy increased TUNEL positive cells and depilation of neoplastic cells in stroma of tumor were observed. Mean deference of histopathological changes and TUNEL positive cells before and after chemotherapy were significant (p