NEU(C-ERBB2 HER2) AND THE EPIDERMAL GROWTH-FACTOR RECEPTOR (EGFR) IN BREAST-CANCER/

One hundred and eighty thousand new cases of invasive breast cancer we re diagnosed in 1992 within the United States. This disease affects ap proximately 1 out of 8 women in the US. Chemotherapy and/or hormonal t herapy have shown some improved disease-free and/or overall survival r ates. Unfortunately, this type of therapy is not directed specifically to the malignant cells, and systemic toxicities are observed. In orde r to develop site-specific treatment, the biology of the disease must be understood such that certain genes or their products which are invo lved in the pathogenesis of the disease can be targeted. Two structura lly related tyrosine kinase growth factors, the epidermal growth facto r receptor (EGFR) and c-erbB-2 (neu) have been identified in human bre ast cancer tissue and, in many instances, may function as oncogenes. T he clinical data related to these two growth factor receptors as progn ostic factors for the disease have been critically evaluated. Several problems with the critical studies were identified, and solutions were proposed to clarify the conflicting results reported in the studies w hich have attempted to examine whether c-erbB-2 (neu), in particular, is a prognostic indicator for breast cancer. In addition, data related to the structure of, ligands for and interaction between the proteins have been reviewed and presented with respect to their role in breast cancer development. A more thorough understanding of the genetic chan ges which contribute to the development of breast cancer will lead to more specific and less toxic treatment for this disease.