Ideas from ASCO

About 30 percent of breast cancers and some other cancers overexpress the HER-2 growth factor receptor. The marker is associated with aggressive disease, rapid progression and shortened survival. Therapies targeted at HER-2 are beginning to demonstrate efficacy in the subpopulation of cancer patients who overexpress the receptor, suggesting that HER-2 is a valid target for treatment as well as a marker.

In normal breast tissue, HER-2 receptors on the cell surface are believed to play a role in normal cell growth by signaling cell division. When cancer cells overexpress HER-2, however, extra receptors form. Their higher density elicits accelerated cell division, contributing to tumor growth...