EPIDERMAL GROWTH-FACTOR RECEPTOR AND C-ERBB-2 EXPRESSION IN NORMAL BREAST-TISSUE DURING THE MENSTRUAL-CYCLE

EGF receptor (EGF-R) and c-erbB-2 are homologous tyrosine kinase trans membrane receptors, They are involved in controlling proliferation, an d probably differentiation, of normal breast epithelial cells, and the ir expression has been linked to the prognosis of breast cancer. Their physiological roles in normal breast tissue remain to be elucidated, as most studies to date have involved breast cancer cell lines. We stu died the location of EGF-R and c-erbB-2 in 100 samples of normal breas t with standard immunohistochemical methods and double-labelling techn iques. EGF-R was mainly expressed on the stroma and myoepithelial cell s, whereas c-erbB-2 expression was exclusively epithelial. An image an alyser was used to quantitate variations in their expression during th e mentrual cycle, EGF-R and c-erbB-2 expression on epithelial cells wa s stronger during the luteal phase than the follicular phase (p < 0.01 for EGF-R). The pattern of expression was also compared with that in 28 breast cancers and 7 fibroadenomas.