Abstract: This study aims to provide the best immune markers for the diagnosis of canine hair follicle tumors, improve the accuracy and shorten the time of tumor diagnosis, and be helpful for the clinical precise treatment. In this study, 26 cases of clinical canine hair follicle tumors were collected, and the tumor cases were labeled with immunohistochemistry (IHC) using immune markers CK5/6, CK8/18, CK19, P63, CD34, CD10, and Vimentin. The results of IHC staining of 26 tumors showed that CD34 was positive in 86.9% follicular tumors; Tumor cells of trichoepitheliomas were specifically positive for CD10 and CK8/18; CK19 was strongly positive in benign trichoepitheliomas and moderately positive in malignant tumors, and CD34 was moderately positive in benign trichoepitheliomas and weakly positive in malignant tumors; CD10 was specifically positive in the peripheral stroma of piloblastoma; Tumor cells in all cases were negative for Vimentin, while mesenchymal cells were positive. The results showed that CK5/6 and P63 can be used as positive markers of all follicular tumors in this study. CD34 can be used as a specific positive marker of hair follicular tumors except pilomatricomas and trichofolliculomas. CD10 and CK8/18 can be used as positive markers of trichoepitheliomas. CK19 and CD34 can be used to distinguish the benign and malignant trichoepitheliomas. CD10 can be used as a specific positive marker of the surrounding stroma of trichoblastomas. Vimentin can be used as a negative marker of hair follicle tumors.

Key words: canine, hair follicle tumors, histopathology, immunohistochemistry, diagnosis, immune markers