Quantitative Analysis of Circulating Plasma DNA as a Tumor Marker in Thoracic Malignancies

cancer patients and may have potential as a tumor marker. The objectives of this study were to develop a controlled, quantitative PCR (QPCR) assay to measure plasma DNA and then evaluate plasma DNA concentra-tions as a tumor marker in patients with thoracic malig-nancies. Methods: We developed a QPCR assay for DNA, using the human -actin gene. Plasma samples were analyzed from 58 patients with esophageal cancer (EC; 20 banked samples and 38 prospectively collected samples) and 25 patients with lung cancer (LC; all prospectively col-lected). Control groups consisting of 51 patients with gastroesophageal reflux disease (GERD; 23 banked sam-ples and 28 prospectively collected) and 11 healthy volunteers were also analyzed