The role of the epidermal growth factor receptor and the c-erbB-2 protein in breast cancer.

Breast cancer cells are derived from epithelial cells lining the ducts of the breast. One of the fundamental characteristics that distinguish tumour cells from normal cells is that cancer cells grow in an apparently unregulated way. Understanding the mechanisms that regulate the growth and differentiation of normal breast epithelial cells and the differences between these systems in cancer cells is one of the central goals of research into the cell biology of breast cancer.