INTERACTION BETWEEN ERBB- RECEPTORS AND HEREGULIN IN BREAST-CANCER TUMOR PROGRESSION AND DRUG-RESISTANCE

The type 1 growth factor receptor family is increasingly recognized as important in the development and maintenance of breast cancer The fam ily currently consists of four closely related members: the epidermal growth factor receptor (ECF-R/erbB-1), erbB-2, erbB-3 and erbB-4. Puta tive ligands which bind directly to or indirectly activate erbB-2/3/4 have been. characterized recently. This still growing family of EGF-re lated growth factors includes gp30, its homolog heregulin (HRG) the ra t homolog neu differentiation factor (NDF) glial growth factors (GLIA) ARIA and a 50 kDa factor from COLO 16 cells. The understanding of the function, biology and interactions of these growth factor receptors a nd their ligands will have far-reaching implications for the prognosis and treatment of breast cancer This review focuses on. advances and f uture directions for further investigations intended to clarify the me chanism and significance of erbB/ligand interactions in breast cancer.