Circulating nucleic acids in plasma and serum: diagnosis and prognosis in cancer.

The presence of DNA and RNA circulating in human plasma and serum is described. The known sources of the DNA/RNA in blood, the ability of these nucleic acids to enter other cells and to express in the recipient cells are considered along with their relationship to metastases. The possible role(s) of the DNA/RNA in personalized clinical diagnosis, monitoring of treatment and prognosis in oncology are discussed.