Clinical Utility of Breast Cancer DNA Markers in Serum

The incidence of early stage breast cancer is rapidly increasing due to advances in methods for its detection. Despite these improvements 20-30% of patients without evidence of metastatic disease at initial diagnosis will subsequently develop a recurrence. New methods to identify high-risk patients requiring aggressive adjuvant therapy and to those not requiring treatment are needed. Because cancer progression has been shown to result from the accumulation of genetic alterations within the cell, assays that identify these genetic events may serve as valuable prognostic indicators. However, studies evaluating tumors are limited as they assess only a single time-point in the disease course and require a biopsy, an invasive procedure that may be associated with potential morbidity. Also this method is not always practical for early stages of disease when detection may be critical. We have recently developed an assay that can identify tumor-associated genetic aberrations from a patient's blood sample. We have demonstrated that these circulating genetic marker alterations correlate with those occurring in the patient's tumors and thus may act as surrogate markers of disease.