IMMUNOHISTOCHEMICAL EXPRESSION OF EPIDERMAL GROWTH FACTOR RECEPTOR IN BENIGN AND MALIGNANT LESIONS OF THE BREAST

The expression of epidermal growth factor receptor (EGFR) was studied in benign and malignant tumors of the breast using a monoclonal antibody of this receptor. The benign lesions were obtained from mastopathy (14 cases), fibroadenoma (12 cases), and malignant lesions, and from papillo-tubular (17 cases), solid-tubular (15 cases), and scirrhous carcinomas (10 cases). The highest incidence of positive EGFR staining was found in the scirrhous carcinomas (70%). The incidence was moderate in tubular carcinomas (60-65%), and low in solid or papillary type (13-35%). Immunolocalization of EGFR staining was divided into 1) luminal-border positive type, 2) cell-membrane positive type, and 3) cytoplasm positive type. In benign lesions, EGFR expression was usually of the luminal border or cell membrane positive type. A heterogeneity of EGFR staining was found in malignant tumors, but evidence suggests in scirrhous carcinoma that EGFR expression is positively correlated with tumor cell proliferation.