The concentration of deoxyribonucleic acid in plasma from 73 patients with colorectal cancer and apparent clinical correlations

Background: Detection of cell-free plasma DNA has considerable potential as a tool for the diagnosis and assessment of the prognosis of many types of cancer. The aim of the present study was to quantify, by spectrophotometry, the cell-free DNA in plasma samples from patients with colorectal cancer at different stages of the disease and to attempt to correlate the resultant values with the clinical picture. Methods: We reviewed the medical reports of 73 patients, who had undergone resection of primary colorectal cancer. Samples of blood had been taken from each patient immediately prior to surgery. DNA was extracted from samples of plasma and quantified, by spectrophotometry, after a storage period of no longer than 2 years in 89% of the cases examined. Results: The mean(±S.D.) concentration of DNA in plasma samples was 108 ± 156 ng/μl. We found a statistically significant correlation between the concentration of DNA and the presence of metastases (mainly liver metastases). Conclusion: The detection and quantitation of cell-free DNA in plasma, using this simple technique, might be of clinical value for the surveillance of colon cancer patients and the detection of metastases.