A Study to Determine the Clinical Significance of Molecular Detection of Breast Cancer in the Blood of Stage IV Breast Cancer Patients

This study is designed to determine whether molecular detection of breast cancer cells in the peripheral blood of Stage IV breast cancer patients is a clinically relevant predictor of progression-free and overall survival. Stage IV breast cancer patients who have measurable breast cancer metastases and are initiating a regimen of systemic therapy are eligible for enrollment. Multi-marker real-time RT-PCR analysis will be performed on peripheral blood specimens from 92 breast cancer patients and 120 healthy volunteers. Peripheral blood specimens from breast cancer patients will be obtained at the time of study entry (prior to initiation of systemic therapy) and at serial time points during follow-up. Subjects will be followed longitudinally until death, although the study has been powered so that the primary objective can be addressed after 12 months of follow-up. Healthy volunteers will be asked to provide a blood sample at time of enrollment but will not be followed.