TUMOUR EPITHELIAL VIMENTIN EXPRESSION IN CANINE CUTANEOUS SQUAMOUS CELL CARCINOMA

Introduction: Tumour epithelial vimentin expression is a marker of mesenchymal differentiation during the epithelialto- mesenchymal transition (EMT) and may be a useful marker of carcinomas with more aggressive behaviour. The aim of this study was to determine vimentin expression pattern and cellular co-localization with β-catenin in canine cutaneous squamous cell carcinoma (SCC). Materials and Methods: Vimentin expression was detected by immunohistochemistry in 26 cases of SCC. Co-localization with β-catenin was evaluated by immunofl uorescence on 6 selected infi ltrative poorly differentiated cases. Results: Normal epidermis, well differentiated neoplastic cords and islands were negative, other then scattered cells, representing melanocytes and epidermal dendritic cells. In SCCs, the percentage of vimentin-immunolabelled neoplastic cells ranged from 0% to 50%, mainly located at the front of tumour invasion, among “basaloid” cells, showing absent/ inconstant membrane and increased cytoplasmic β-catenin expression. In two cases of spindle cell SCC, neoplastic cells were strongly immunolabelled. Vimentin positive cells were present also within neoplastic emboli and lymph node metastasis. Few cells showed co-localization of vimentin and nuclear β-catenin. Conclusion: Our results suggested that tumour epithelial vimentin expression could correlated with poor histological differentiation of canine SCC. Its expression in infi ltrative cells showing aberrant subcellular localization of β-catenin suggests that these cells undergo EMT.