Nuclear survivin expression as a potentially useful tool for the diagnosis of canine cutaneous sebaceous lesions

Background- Sebaceous glands are specialized cutaneous adnexal glands, which work under constant hormonal control to produce sebum. They can give rise to several proliferative lesions, such as hamartoma, hyperplasia and neoplasms (adenoma, epithelioma and carcinoma). Their nomenclature is currently confusing, both in veterinary and in human medicine, owing to the difficulty of differentiating between some of these lesions. Methods- The present study used immunohistochemistry to determine the expression levels and patterns of survivin and Ki67 in five samples of normal canine skin and 44 cases of canine cutaneous lesions with sebaceous differentiation (10 hamartomas, nine hyperplasia, eight adenomas, eight epitheliomas and nine carcinomas). Results- In normal glands, survivin, as well as Ki67, was expressed in scattered reserve cells. In hamartomas, survivin was more highly expressed than in normal skin, indicating a possible role of this molecule in the pathogenesis of these congenital lesions. In tumours, a moderate or high level of survivin and Ki67 expression (more than two and four and more than two positive cells, respectively) were significantly correlated with a malignant histotype, infiltrative growth and a moderate or high number of mitoses (more than two). Conclusions and clinical importance- The level of survivin expression increased with increasing malignancy, designating survivin as a new diagnostic marker in the assessment of malignancy of sebaceous tumours.