The significance of CD8/FOXp3 ratio in transmissible canine venereal tumors

Venereal tumors (VT) are tumors that occur in both male and female dogs, usually in the external genitalia, and can be transmitted through mating. The tumor is generally more common in young and sexually active animals. Studies on these tumors have shown that the tumor microenvironment and CD8 and FOXp3 lymphocytes play a significant role in tumor development and prognosis. This study investigated the ratios of these cells and their relationship with the tumor in cases of VT in dogs. Tumor biopsies from 5 dogs (3 male, 2 female) with VT were used in the study. In cases diagnosed by routine cytological and histopathological methods, CD8 and FOXp3 expressions were demonstrated using real-time PCR and calculated using the ΔΔCt method. CD8 expression ratios ranged from 0.19 to 0.42, while FOXp3 expression ranged from 0.10 to 0.19, and the CD8/FOXp3 ratio ranged from 1.81 to 4.77. A significant difference in CD8 expression was observed between males and females, and the CD8/FOXp3 ratio was also found to be statistically significant. When histopathological and PCR findings were evaluated together, it was concluded that tumor regression occurred in cases with a high CD8/FOXp3 ratio, that this was more pronounced in females, and that this ratio could be used in tumor prognosis and treatment monitoring.