Cell free circulating tumor nucleic acids, a revolution in personalized cancer medicine

Innovative diagnostics are becoming an essential component in personalized cancer medicine. These diagnostics are increasingly based on cell-free nucleic acids and membrane vesicles. Isolating and sequencing cell free circulating DNA (cfDNA) in plasma may progressively substitute tumor biopsies. A small albeit now detectable fraction of cfDNA correspond to circulating tumor DNA (ctDNA). In this review, we describe the pre-analytical procedures for collecting ctDNA from plasma, since these procedures should be optimized within laboratories depending on the available infrastructures. We also provide an overview of the technological breakthrough in ctDNA Isolation for instance digital PCR methods and next generation sequencing techniques and discuss their key challenges. The clinical implementations of liquid biopsy and more specifically ctDNA in cancer management are reviewed. We predict in the near future, ctDNA will be used more routinely to guide cancer treatment and provide a new approach to personalize treatment in precision medicine.