SURVIVIN EXPRESSION IN CANINE HAIR FOLLICLE TUMOURS

Introduction: Despite the vast body of knowledge about survivin expression in skin tumours, no data are available concerning survivin expression in hair follicle tumours. The aim of this study was to evaluate the survivin expression pattern in canine hair follicle tumours. Materials and Methods: Survivin expression was investigated by immunohistochemistry in four normal canine skin samples, 30 hair follicle tumours (six pilomatricomas, eight infundibular keratinising acanthomas-IKA, six trichoepiteliomas and 10 trichoblastomas) and two basal cell carcinomas (BCCs). A semi-quantitative method was used to analyse results. Mitotic index was evaluated morphologically. Results: Nuclear immunolabelling with positive mitosis was observed among basal cells of the normal epidermis, outer root sheath, hyperplastic epidermis overlying the tumours and neoplastic cords of IKA cases. Scattered positive matrical cells were present in the bulb of normal hair follicles. The highest number of positive cells (O50%) were present in pilomatricomas and trichoepitheliomas, among cells with matrical differentiation, and in some cases of trichoblastoma. Few or absent positive cells were observed in BCCs.Conclusions: In accordance with previous studies of the human hair follicle, the present results suggested that survivin could representa key molecule in the maintenance of cellular subpopulations of the canine hair follicle, as well as of tumours deriving from these cells: trichoepithelioma, trichoblastoma and pilomatrixoma.[...]