Expression of Foxp3 in Fibromas and Fibrosarcomas of Skin and Subcutaneous Tissue in Dogs.

BACKGROUND/AIM: Foxp3 is a transcription factor responsible for the formation of T regulatory lymphocytes. Foxp3 expression can be associated with either neoplastic progression or regression. The aim of the study was to evaluate Foxp3 expression in soft tissue tumours (fibromas and fibrosarcomas) of skin and subcutaneous tissue in dogs and to describe its relationship with tumour malignancy grade. MATERIALS AND METHODS: The study was conducted on 71 skin and subcutaneous tumours including 31 fibromas and 40 fibrosarcomas. The samples underwent histological and immunohistochemical evaluation using anti-Foxp3, anti-Ki, and vimentin antibodies. RESULTS: Cytoplasmic expression of Foxp3 protein in the cutaneous and subcutaneous fibrosarcomas in dogs was confirmed. Moreover, a positive relationship between the expression of Foxp3 and tumour malignancy grade and between Foxp3 and Ki-67 expression was noted. CONCLUSION: A positive correlation between the Foxp3 expression intensity and malignancy grade suggests a significant role of Foxp3 in the carcinogenesis of skin and subcutaneous fibrosarcomas in dogs. Increased expression of Foxp3 may have a positive effect on the progression of cancer.