EXPRESSION OF ESTROGEN, PROGESTERONE AND EPIDERMAL GROWTH-FACTOR RECEPTORS IN PRIMARY AND METASTATIC BREAST-CANCER

The prognostic value of epidermal growth factor receptor (EGFR) expres sion and its biological role in estrogen receptor-positive (ER(+)) and ER-negative (ER(-)) primary breast cancer is controversial. In this s tudy, distributions of ER, progesterone receptor and EGFR have been es tablished using immunohistochemistry in both primary breast tumors and their matched axillary lymph node metastases of 26 patients or their matched distant metastases of 2 patients. In addition, 5 patients with bilateral breast cancer were studied. ER(+) tumor cells were detected in 22 (69%) and EGFR(+) tumor cells were detected in II (34%) primary breast carcinomas. Expression of ER and EGFR was inverse regarding th e individual tumor cells in both primary tumors and metastases. Relati onship of EGFR expression with poorly differentiated and large breast tumors was observed. Furthermore, primary tumors with a predominant lo bular component were ER(+) and, with one exception, EGFR(-). Invasive ductal carcinomas were more frequently EGFR(+). No apparent difference s in receptor expression were observed between primary tumors and lymp h node metaseases or chronously or metachronously occurring bilateral breast cancers. Only one ER(+) primary tumor showed a switch to EGFR e xpression in the involved lymph node. Our study shows that a shift in receptor phenotype between primary tumors and lymph node metastases is a rare event and, thus, additional analyses of involved lymph nodes w ill not likely serve as a better predictor for response to anti-estrog en therapy. We conclude that expression of EGFR is not a prerequisite for development of metastases. (C) 1995 Wiley-Liss, Inc.