In this study, we aimed to evaluate the proliferative, metastatic and apoptotic capacities of TVT cases, which are in various phases of development, by using immunohistochemical markers. The material of this study consisted of twelve female and six male dogs diagnosed with TVT brought to our department between 2007 and 2020 years. Diff-quick staining was applied to the smear taken from tumoral masses for cytological examinations. Tumoral tissues from dogs were fixed in a 10% neutral buffered formaldehyde solution. After routine tissue procedures Hematoxylin & Eosin stain was applied to the sections. Tissue sections were investigated under a light microscope and photographed. Immunohistochemical staining was performed on the tissues using the avidin-biotin immune peroxidase complex method. As a result of macroscopic, cytological and histopathological examinations, TVT positive cases were divided into three according to their developmental stages. While the expression of PCNA, MMP-9, mutant p53 and Bcl-2 increased significantly in progressive cases compared to regressive and stable cases, Bax expression increased significantly in regressive cases compared to progressive and stable cases. In conclusion, we thought that the mentioned markers are very useful for understanding the prognosis of TVT, the tumor aggressiveness and the survival of the malignant cells.