Role of P-cadherin in the pathogenesis of mammary Paget disease

AC Han, MD, PhD

The Reading Hospital Regional Cancer Center, West Reading, PA

AIM: Cadherin proteins are important in mediating cell sorting and adhesion. P-cadherin is normally expressed in basal epithelial cells located at the dermal-epidermal junction, but not expressed in simple epithelia. We wanted to determine the role of P-cadherin in the pathogenesis of Paget disease of the breast. METHODS: Cases of Paget disease of the breast were examined for the expression of P-cadherin by paraffin immunohistochemistry. RESULTS: All four cases of Paget disease examined to date showed expression of P-cadherin in the malignant tumor cells and the adjacent keratinocytes. Some cases where nests of tumor cells were present, the P-cadherin was localized to the outer cells in contact with squamous cells, but not in the junction between tumor cells. CONCLUSIONS: P-cadherin is abnormally expressed in malignant cells of Paget disease and may mediate migration and adhesion by facilitating homotypic interaction of tumor cells to the P-cadherin expressing keratinocytes.

KEY WORDS: Adhesion protein, oncogene, immunohistochemistry.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Molecular Pathology.