Interim results of two prospective trials measuring plasma total DNA and methylated genes before and after surgery, or chemotherapy, in patients with non-small cell lung cancer (NSCLC)

7123 Background: Measuring DNA in plasma using quantitative RT-PCR is a promising method for surveillance of NSCLC. This strategy has the potential to assess response more accurately or quickly than radiologic tests, or to confirm the success of surgical resection and select patients for adjuvant therapy. Methylated genes may be more specific than total DNA for the presence of cancer. Methods: We are conducting two prospective trials measuring total DNA, and 10 commonly hypermethylated genes in the plasma of NSCLC patients before and after therapy. For patients undergoing surgery, plasma samples are collected before, and at three timepoints after surgery (3–8 d, 2–5 w, 2–4 m). For patients on chemotherapy, collections are before, and coincident with up to 3 radiologic response assessments. DNA is extracted from a fixed volume of plasma, and measured using quantitative PCR of the β-Actin gene. After treating DNA with sodium metabisulfite, methylation-specific RT-PCR is performed to amplify the promoter reg...