Expression of epidermal growth factor receptor in breast cancer, from early stages to advanced disease

Epidermal growth factor receptor was determined in 106 newly diagnosed breast cancer patients, using the biochemical method. The group consisted of 58 patients in stage I-II, and 48 patients in stage III-IV. Although a significant inverse correlation was found between EGF-R status, and ER or PR status, quantitative content of EGF-R did not correlate either with quantitative ER, or PR levels. The ER/PR content was similar in all clinical stages, suggesting their stability during the clinical course of the disease. EGF-R content was significantly higher in stage IV, compared to stage I, while intermediate clinical stages and all substages did not differ according to the EGF-R content. EGF-R was confirmed as a weak prognostic factor within clinical stages. However, in a whole group, the overall survival was significantly better in patients whose tumors EGF-R content was lower than 26 fmol/mg, compared to those with higher ERF-R content. EGF-R content was highly predictive for the response to systemic endocrine treatment, in metastatic breast cancer patients. In locally advanced breast cancer a trend towards higher levels of EGF-R was found in inflammatory breast cancers, compared to non-inflammatory ones. Slightly higher levels were found in responders to local non-endocrine primary treatments (radiotherapy with or without chemotherapy), compared to non-responders, suggesting the possible predictive role of EGF-R for the response to such treatments. Our results emphasized the usefulness of quantitative receptor determination suggesting the relative stability of EGF-R content during the clinical course of breast cancer, its independence from ER, its significant predictive and weak prognostic values, and a possible correlation with the aggressiveness of the disease, and response to non-endocrine treatments.