ABSTRACT
Division of Molecular and Cellular Medicine, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan. aEmail: muriel.th@hotmail.com bEmail: tochiya@ncc.go.jp *Corresponding author
Prior to the discovery of the double-helical structure of DNA by Watson and Crick, Mandel and Métais reported the presence of extracellular nucleic acids in the blood plasma (Mandel and Métais 1948). Due to lack of interest and proper molecular biological techniques to study circulating nucleic acids, this noteworthy work was unfortunately buried for almost 20 years until Tan and colleagues demonstrated the presence of circulating DNA in patients with systemic lupus erythematosus (Tan et al. 1966). The real breakthrough took place in 1994 when two groups detected the presence of mutated tumor-associated oncogenes in the plasma of patients with cancer (Sorenson et al. 1994, Vasioukhin et al. 1994). Since then, many studies demonstrated the presence of several extracellular nucleic acids (DNA, mRNA, miRNA) at high concentration in the blood of diseased patients (Shinozaki et al. 2007, Lawrie et al. 2008, Mitchell et al. 2008). These data were remarkable because they opened the path to new alternative approaches to the usual cancer screening tests that are invasive and ineffi cient in the early stages’ detection.
