Identification and interpretation of epidermal growth factor and c-erbB-2 overexpression.

Overexpression of normal cellular genes may be one mechanism by which malignant cells can acquire a selective growth advantage. The epidermal growth factor receptor and the c-erbB-2 protein are members of the erbB family and are good examples of genes that appear to act through this mechanism. Molecular and biochemical analyses of these two proteins also illustrate how studies of growth factors, growth factor receptors and oncogenic retroviruses may lead to new approaches to diagnosis and treatment. In particular, overexpression of these growth factor receptors has identified clinical subgroups that may respond differently to chemotherapy and provides the opportunity for antibody targeted therapy. Overexpression of these proteins can be identified using immunocytochemistry on both histological sections and fine-needle aspirates, thus enabling these parameters to be assessed preoperatively and to be monitored during therapy.