OVEREXPRESSION OF P53, C-ERBB-2 AND EPIDERMAL GROWTH-FACTOR RECEPTOR IN HUMAN BREAST CARCINOMAS

Overexpression of p53 protein, epidermal growth factor receptor (EGF-R ), and c-erbB-2 protein was assessed by immunohistochemical staining o f formalin-fixed, paraffin-embedded tissue from 64 invasive breast tum ors. The correlation between abnormal expression of each protein and v arious disease parameters, including lymph node metastasis and histopa thologic type and grade was analyzed. Despite the previous proposal, n o significant correlation was found between lymph node metastases and overexpression of each gene In the primary tumors. In addition, some m etastatic lesions did not always exhibit overexpression, even if it wa s evident in the primary tumors. Overexpression of c-erbB-2 protein co rrelated well with Bloom's histological grading. p53 expression was de tected most often in tumors with hyperchromatism and more frequent mit osis. Overexpression of c-erbB-2 protein occurred more frequently in p 53-positive tumors. The results indicate that abnormal expression of p 53 protein causes genetic instability in the early stage of tumor deve lopment, resulting in subsequent overexpression of other oncogenes.