EN
E-cadherin is an adhesion molecule playing a crucial role in the maintenance of epithelial tissue architecture. Deterioration of its functions, resulting in the loosening of intercellular linkages, may be conducive to neoplasm progression and metastasis formation. The aim of this study was to provide an immunohistochemical evaluation of E-cadherin expression in 6 sections of a normal canine mammary gland and in 8 benign and 36 malignant epithelial neoplasms, as well as to determine the relationship between the level of E-cadherin expression and the histological type and grade of tumour. In malignant tumours, a decreased level of E-cadherin expression was observed when compared to a normal gland and benign tumours, which depends on the histological type and malignancy grade. Moreover, a progressive decrease in E-cadherin expression was observed in mammary carcinomas with an increasing malignancy grade. This suggests that decreasing E-cadherin expression may contribute to the differentiation of poorly-differentiated neoplastic cells to an invasive phenotype, and may be one of the factors triggering the metastatic cascade.