Phyllodes tumor of the breast: EGFR family expression and relation to clinicopathological features

The expression of EGFR family members was examined by immunohistochemistry in 22 phyllodes tumors, and the results were evaluated together with immuno histochemical findings for proliferation markers Ki67 and BM28, and the tum or suppressor gene product p53. Light and electron microscopy were performe d in all cases. Clinical information was obtained from the medial records. We did find that expression of EG FR, c-erbB-3 and c-erbB-4 proteins could be detected in the neoplastic mesenchymal cells, and that the expression in creased with increasing malignancy. Increased expressions of Ki67, BM28, p5 3 and EGFR family members in neoplastic cells were associated with malignan cy and unfavorable clinical course. Furthermore, the expression of ER-a and PR in the epithelial cells of phyllodes tumors was increased compared to t hat in normal breast epithelium. Finally, the application of electron micro scopy helped to identify a group of malignant rumors, revealing neoplastic cells with characteristic nuclear indentations, as well as an increasing nu mber of myofibroblasts.