Cell-free nucleic acids in plasma, serum and urine: a new tool in molecular diagnosis

There has recently been an upsurge of interest in the analysis of circulating nucleic acids (DNA and/or RNA) in blood plasma or serum as a clinical diagnostic tool. Occasional earlier reports suggested the existence of circulating nucleic acids, but the potential clinical implication was not realized until 1996, when DNA with tumour-specific characteristics was demonstrated in the plasma/serum of cancer patients. This finding opened up possibilities for non-invasive cancer diagnosis. Potential applications have been reported in cancer diagnosis, prenatal diagnosis, transplantation and traumatology. Some of the findings are on the verge of being translated into clinical use. DNA is also now being sought in other body fluids such as urine.