A blood-based DNA test for colorectal cancer screening

Early detection of colorectal tumors through the identification of mutant DNA in serum or plasma could have a substantial impact on morbidity and mortality. Somatic mutations are specific biomarkers for neoplastic cells, but their detection requires sensitive assays, as the number of circulating mutant molecules is small compared to the number of normal DNA molecules. A newly developed method can provide this sensitivity and at the same time precisely quantify the fraction of mutant molecules present in the clinical sample. Using this technology, it has been found that more than half of patients with early stage disease contain mutant DNA in their circulation.