Tumor Specific Plasma DNA

Study Summary

In 2011, there was an estimated 233,000 cases of invasive breast cancer, and 39,970 deaths from breast cancer in the United States. The vast majority of patients are diagnosed with Stage I-III resectable and potentially curable disease, and for these patients, the most pressing questions are whether adjuvant endocrine or chemotherapy are indicated, and if so, how to determine whether these treatments are working. Adjuvant systemic therapy reduces relative recurrence rates by 30-50%, depending on the age of the patient and tumor characteristics. However, patients with early stage disease often do not bear measurable markers of disease such as an elevated cancer antigen 27-29 (CA27.29) or circulating tumor cells. Patients with early stage breast cancer are typically treated with adjuvant therapy based on historical evidence showing that such therapy prolongs survival in this population. Lung cancer is the most common malignancy and the leading cause of cancer-related death in the U.S. Approximately 220,000 new cases of lung cancer are diagnosed in the U.S. every year. Unfortunately, lung cancers are often diagnosed at later stages than breast cancer, due in part to little/no effective screening for lung cancer. As with breast cancer, patients are commonly treated with chemotherapeutic agents, but treatment regimens can take several weeks to months to elicit clinically detectable anti-tumor effects. A biomarker to assess early tumor response to therapy would benefit this patient population. The contents of dying tumor cells can be detected in the bloodstream, and this may be enhanced by the leaky vasculature of solid tumors. Protein biomarkers of tumor cell death are difficult to detect due to the complex nature of plasma and the lack of technical sensitivity. In contrast, DNA is easier to detect through polymerase chain reaction (PCR) amplification. Indeed, circulating tumor DNA has been detected in plasma from patients with osteosarcoma, breast cancer, and colorect