ANOMALOUS EXPRESSION OF P-CADHERIN IN BREAST-CARCINOMA - CORRELATION WITH E-CADHERIN EXPRESSION AND PATHOLOGICAL FEATURES

Previous studies on the cell-cell adhesion molecules P- and E-cadherin have shown that P-cadherin is not expressed in breast cancer. In cont rast, the expression of E-cadherin is a normal event in these tumors, but a reduction in the levels of this molecule is neoplastic cells is associated with the histological type, high histological grade, greate r tumor size, and metastasis The expression pattern of P- and B-cadher in were immunohistochemically studied in tissue sections from normal b reast tissue, benign breast lesions, and 57 infiltrating breast carcin omas. Cadherin expression was analyzed parallel with pathological feat ures and the immunohistochemical expression of estrogen and progestero ne receptors ill breast carcinomas, P-cadherin was detected in the myo epithelial cells and E-cadherin in luminal epithelial cells from norma l breast and benign breast lesions. P-cadherin expression teas detecte d in 9 of 45 cases (20%) of infiltrating ductal carcinomas of no speci al type; none of the special histological types that were analyzed (7 infiltrating lobular carcinomas, 3 colloid carcinomas, and 2 infiltrat ing papillary carcinomas) expressed P-cadherin. In infiltrating ductal carcinomas, P-cadherin expression correlated significantly with a red uction in E-cadherin expression, histological grade (all cases were gr ade III tumors), and hormone receptor content (8 of 9 cases were estro gen and progesterone receptor negative). Although E-cadherin was not f ound In the 7 infiltrating lobular carcinomas, it was present in the r emaining histological types and was preserved in 15 infiltrating ducta l and 3 colloid and 2 papillary carcinomas and was reduced is 30 infil trating ductal carcinomas In addition, a reduction in B-cadherin expre ssion was significantly associated with high histological grade and a lack of steroid hormone receptors in infiltrating ductal carcinomas. N o apparent relationship was found between P- and E-cadherin expression and tumor size and axillary lymph node metastasis. The distinct patte rns of P- and E-cadherin expression observed in this study strongly su ggest a differential role for these cadherins in human breast carcinog enesis.