Circulating tumor DNA in relapse prediction: a gold mine on the rise

Nominated in the top 10 breakthrough technologies in 2015 (1), the use of liquid biopsy in cancer diagnostics has drawn a lot of attention in scientific and industrial communities. It is non-invasive by nature, and can be accessed from a blood draw, from cerebrospinal fluid (2) or even from urine (3). Circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) are among the most promising detection markers in liquid biopsy (4). Although FDA has approved one CTC test kit for prognosis of cancer patients’ survival assessment, CTC analysis for clinical implications remains controversial. In contrast, the potential of ctDNA in tumor detection is much more encouraging. Studies demonstrated that the half-life of ctDNA is around 2 hours, allowing the real-time tracking of genomic alternations happening in the tumor (5).