[Immunohistochemical detection of EGF-receptors in breast cancers]

We examined the possibility of a quick and easy-to-perform way to determine the EGF receptor status in primary breast cancer cells by immunohistochemical staining. For this, we used two different monoclonal antibodies on corresponding tissue slides (Gullick, London; Mendelsohn, New York). The staining was interpreted by a semiquantitative histoscore. With both antibodies, we were able to detect EGF-R in breast tumours. We examined 80 tumours. 15 respectively 21% were EGF-R rich. 25% of the tumours were classified EGF-R poor. In 64 (54%) we were not able to detect EGF-R. The judgement of the EGF-R status by the different antibodies was identical in 80%. The results were also compared with the oestrogen receptor status (ER). We did not find a significant accumulation of EGF-R positive tissues in the group of ER-negative tumours (11/28 respectively 16/32). Nevertheless most ER-positive tumours showed a negative EGF-R receptor score (32/52; 27/48). These results are comparable to the studies of the Sainsbury group. In addition we compared the EGF-R of our tumours also with other parameters for the prognosis of breast cancer such as lymph node status, histological grading and menopausal status. We found, that nearly two thirds of the EGF-R negative tumours were lymph node negative. Only 18% of the lymph node negative tumours had a positive EGF-R status in both techniques. The results of immunohistochemical staining were also compared with a radio-receptor assay. The results were identical in 85% of the cases.