Quantification of plasma cell-free DNA in patients with gastric cancer.

BACKGROUND The circulating DNA concentration and integrity was examined by a quantitative polymerase chain reaction (qPCR) in the plasma from patients with gastric cancer and their diagnostic value for the detection of gastric cancer assessed. PATIENTS AND METHODS Plasma samples were collected preoperatively from 53 patients with gastric cancer and 21 healthy controls. qPCR was performed using two different primer sets for the beta-actin gene, amplifying short and long segments. DNA integrity was calculated as the ratio of concentrations in both assays. RESULTS The DNA concentrations in the short and long assays of the gastric cancer patients were significantly higher (p=0.03 and p<0.0001, respectively) than those of the control group. The DNA integrity was also higher in cancer patients than that of the controls, however the difference was not significant (p=0.07). CONCLUSION The plasma DNA concentration assay may serve as a new diagnostic marker for the screening and monitoring of patients with gastric cancer.