Trial of ZD1839 (Iressa) and Tamoxifen in Breast Cancer Patients

The researchers want to learn whether ZD1839 can improve the activity of tamoxifen, a drug that participants will receive for the treatment of the type of breast cancer being studied. Tamoxifen medicine is part of the standard treatment for the type of breast cancer being studied. It is approved for the treatment of this problem. In order to help the researchers understand how the cancer responds to these medicines, the researchers will take a small tissue sample (biopsy) of the breast cancer before beginning treatment and after two weeks of treatment, at 6 weeks and when surgery is done as part of treatment for the cancer. If participants do not respond to treatment, another biopsy will be done to see why the participants did not respond. These samples will also be collected to look at different characteristics of the cancer. The researchers cannot and do not guarantee that participants will benefit if they take part in this study