Circulating nucleic acids in plasma and serum: an overview.

The recent interest in nucleic acids in plasma and serum has opened up numerous new areas of investigation and new possibilities for molecular diagnosis. In oncology, tumor-derived genetic changes, epigenetic alterations, and viral nucleic acids have been found in the plasma/serum of cancer patients. These findings have important implications for the detection, monitoring, and prognostication of many types of malignancies. In prenatal diagnosis, the discovery of fetal DNA in maternal plasma and serum has provided a noninvasive source of fetal genetic material for analysis. This development has important implications for the realization of noninvasive prenatal diagnosis and has provided new methods for the monitoring of pregnancy-associated disorders. Plasma DNA technology has also found recent applications in the fields of organ transplantation, posttrauma monitoring, and infectious agent detection. Future areas of study include circulating RNA in plasma and the elucidation of the biology of release, clearance, and possible functionality of plasma nucleic acids.