IMMUNOHISTOCHEMICAL IDENTIFICATION OF THE EPIDERMAL GROWTH-FACTOR RECEPTOR (EGF-R) IN PARAFFIN-EMBEDDED BREAST-CANCER SPECIMENS CORRELATIONS AND CLINICAL RANKING

Analyses of the level of expression of the epidermal growth factor receptor (EGF-R) of breast cancer tumours may add independent information about the prognosis for individual patients. Furthermore, the use of monoclonal antibodies directed against EGF-R as therapeutic tools (e.g., Mab 425) requires a reliable evaluation of the individual EGF-R content. Various analytical methods have been published, including (1) biochemical detection of EGF-R by a radiolabelled physiological ligand, ((125)1)EGE (2) enzymatic analyses of EGFR content (IEMA), (3) immunological analyses of EGF-R content with a monoclonal antibody (ELISA), and (4) immunhistochemical EGF-R detection. Studies with immunohistochemical analyses of EGF-R overexpression in formalin-fixed, paraffin-embedded tumour samples are rare. In a retrospective study, we examined the clinical data from 142 patients and the EGF-R expression in their formalin-fixed, paraffin-embedded tumour samples. The average follow-up was 69 months. EGF-R expression was compared to oestrogen (ER) and progesterone (PgR) receptor expression, histological grade, tumour size, lymph node metastases and menopause. 52 of 142 tumours were EGF-R positive. EGF-R overexpression correlated with high tumour grade, large tumours and elevated numbers of lymph node metastases. There was no significant correlation between ER or PgR and EGF-R expression. Determination of EGF-R overexpression revealed no significant difference in disease-free interval (DFI) or overall survival (OS). In this study, the determination of EGF-R in formalin-fixed, paraffin-embedded tumour samples proved feasible. Unfortunately, this did not add any additional information concerning DFI or OS.