Transmissible Venereal Tumor: Cell Proliferation (Agnor) and Response to Chemotherapy Correlated With Cytomorphological Classification

Abstract

Transmissible venereal tumor (TVT) is a contagious neoplasm of round cells that occurs naturally and that affects mostly the genitalia. The TVT has been classified according to the predominant cell type as follows: linfocytoid, plasmacytoid and mixed. Various degrees of aggressiveness with wide range of biological behavior have been described based on this cell morphology. The present study aimed to evaluate the rate of cell proliferation, by cytochemical AgNOR method, and response to chemotherapy correlated with the cytomorphological classification of TVT. The results of the 22 cases showed that TVT was identified more frequently in female, adults and mixed-breed dogs. Plasmocytoid-classified tumors required a greater number of vincristine sulfate sessions, have higher cell proliferation and were the most resistant to chemotherapy, requiring additional treatment with doxorubicin. Based on these results, we can infer that the plasmacytoid pattern might have a more aggressive behavior compared to other cell types.

Proliferative activity of various grades and types of breast carcinoma using AgNOR (Argyrophilic Nuclear Organizer Region) expression and its prognostic significance

“…The TVT is spread by implanting viable tumor cells in injured mucosal tissue, and the clinical expression is determined by the host's immune status (Albanese et al 2006). Reis Filho and colleagues (Reis Filho et al 2020) used the cytochemical AgNOR method to assess cell proliferation rates and chemotherapy response, which were associated with the cytomorphological classification of TVT. The results of the 22 cases in the study revealed that TVT was found more commonly in female, adult, and mixed-breed dogs.…”

Lomustine therapy for vincristine-resistant canine transmissible venereal tumor: a case report

“…Definitive diagnosis may be performed by cytology (Lorimier & Fan, 2007). Vincristine sulfate is generally considered to be the most effective treatment for canine CTVT (Gonzalez et al, 2000;Martins et al, 2005;Nak et al, 2005;Scarpelli et al, 2010;Reis Filho et al, 2020); however, some tumors are resistant to this drug. Vincristine is preferred because of its high effectiveness (complete remission in more than 90% cases), low cost, and mild toxicity (Woods, 2020).…”