On the role of survivin as a stem cell biomarker of canine hair follicle and related tumours

Background Survivin has been identified as one of the most cancer-specific molecules, with a dual function of apoptosis inhibitor and orchestrator of cell division. Hypothesis/Objectives Based on our recent results obtained during the study of the role of survivin in epithelial-to-mesenchymal transition, we investigate its potential role in maintenance of stemness in both the normal canine hair follicle and related tumours. Methods We performed a simultaneous evaluation, by immunofluorescence, of the expression of survivin and CK15. CK15 was selected as a marker for epidermal and hair follicle stem cells, based on its ability to identify hair follicle stem cells in the normal hair follicle and in canine follicular tumours. In this study, six cases were selected from the cases of hair follicle tumours evaluated in previous studies, based on the highest immunoreactivity for survivin and CK15. Three samples of healthy canine skin were also included as a normal control. Results A partial co-localization of the molecules was observed in normal hair follicles, as well as in trichoepitheliomas and trichoblastomas. In particular, a different co-expression was observed in relationship to the hair follicle cycle stage. Conclusions and clinical importance These findings suggest that survivin could play an important role in the maintenance of the hair follicle cycle as well as in tumour initiation and maintenance of cancer stem cells.