Expression of the epidermal stem cell marker p63/CK5 in cutaneous papillomas and cutaneous squamous cell carcinomas of dogs

• Published in: Research in veterinary science 2021-03, Vol.135, p.366-370
• Main Authors: Sanz Ressel, B.L., Massone, A.R., Barbeito, C.G.
• Format: Article
• Language: English
• Subjects: Animals; Biomarkers, Tumor - metabolism; Canine skin; Carcinoma, Squamous Cell - genetics; Carcinoma, Squamous Cell - veterinary; Cell differentiation; Cell self-renewal; Cytokeratin; Cytokeratin 5; Dog Diseases - metabolism; Dogs; Epidermal tumours; Immunohistochemistry; Keratinocytes; Laboratories; Markers; Monoclonal antibodies; p63; Papilloma - genetics; Papilloma - veterinary; Pathogenesis; Phenotypes; Phosphatase; Skin cancer; Skin Neoplasms - pathology; Skin Neoplasms - veterinary; Squamous cell carcinoma; Stem cells; Tissue microarrays; Tumors; Veterinary medicine
• ISSN: 0034-5288; 1532-2661
• DOI: 10.1016/j.rvsc.2020.10.018

Cutaneous papillomas (CPs) and cutaneous squamous cell carcinomas (CSCCs) are usual epidermal tumours in dogs. CPs and CSCCs probably arise from the neoplastic transformation of the keratinocytes within the stem cell compartment, since these cells are the only keratinocytes that would reside long enough to accumulate the number of molecular alterations to drive the progression towards a tumour cell phenotype. However, the role of these cells in common epidermal tumours in dogs is still unknown. Thus, the purpose of this study was to evaluate the immunohistochemical expression pattern of p63 together with CK5, molecular markers of epidermal stem cells, on sections of tissue microarrays constructed from canine samples of CP and CSCC to investigate the contribution of stem cells in those canine tumours. p63/CK5 coexpression was retained in most basal and some suprabasal cells in CPs and CSCCs. In addition, increased coexpression of these molecules was observed in a group of CPs and CSCCs, as a result of a higher p63 expression. These results suggest that the coexpression of p63/CK5 may mark epidermal keratinocytes that possess self-renewal capacity rather than only stem cells, and suggest that transit amplifying cells, and even differentiated keratinocytes, may also contribute to the pathogenesis of epidermal tumours in dogs. •p63/CK5 expression is present in most basal and some spinous cells in normal epidermis in dogs.•p63/CK5 expression is increased in some cutaneous papillomas and cutaneous squamous cell carcinomas in dogs.•The results suggest that the coexpression of p63/CK5 may mark epidermal keratinocytes that possess proliferative capacity rather than only stem cells.