[Erb-2 overexpression in breast cancer]

Overexpression of the Erb B-2 receptor plays an important role in the pathogenesis of breast cancer. It results in the formation of heterodimers consisting of Erb-B2/Erb B-3 receptors which have an ability to produce stable and external factors independent mitotic stimuli. Together with an autocrine stimulation of neoplastic cell proliferation by heregulin and cyclooxygenase 2 activation it is a significant factor in carcinogenesis. Overexpression of Erb B-2 seems to be an independent negative prognostic factor in breast cancer. Its predictive value is not clear-cut. It is suggested that breast cancer showing Erb B-2 overexpression is more sensitive to treatment with anthracyclines and less to CMF. The anti-Erb B-2 monoclonal antibody (trastuzumab) is used in treatment of metastatic breast cancer both as a single drug and in combination with chemotherapy.