These studies provide clinical evidence for a subpopulation of chemotherapy-resistant breast cancer-initiating cells. Lapatinib did not lead to an increase in these tumorigenic cells, and, in combination with conventional therapy, specific pathway inhibitors may provide a therapeutic strategy for eliminating these cells to decrease recurrence and improve long-term survival.

The antitumor activity of tamoxifen in patients with breast cancer may be determined, in part, by tumor levels of AIB1 and HER-2. Thus, AIB1 may be an important diagnostic and therapeutic target.

No abstract