Figure 1.

Liquid biopsy utilizing plasma or blood samples. (A) CTC, free nucleic acids and EV are taken up by bloodstream peripheral to tumors. It is feasible to examine point mutations, amplifications, deletions, epigenetic changes, and translocations in ctDNA by drawing blood samples from cancer patients; (B) The most common techniques for analyzing ctDNA in blood samples include digital PCR, real-time PCR, BEAMing, COLD-PCR and next-generation sequencing (Reproduced with permission from Ref. 20, Elsevier). CTC, circulating tumor cells; EV, extracellular vesicle; ctDNA, circulating tumor DNA; cfDNA, cell-free DNA; PCR, polymerase chain reaction; BEAMing, bead, emulsion, amplification, magnetic; COLD-PCR, co-amplification at lower denaturation temperature-polymerase chain reaction.