Liquid biopsy for tumor analysis offers the potential for noninvasive access using a blood draw instead of a surgical procedure. In addition, sampling the blood can detect tumor DNA even when the location of a tumor is unknown. However, circulating tumor DNA is usually scarce, and it can be difficult to collect enough blood for adequate detection, especially in cases where tumors are small. Martin-Alonso et al. addressed this difficulty by developing two different types of priming agents that protect circulating DNA from destruction (see the Perspective by Moser and Heitzer). With these agents, more DNA remains in the bloodstream and is easier to detect even in small blood volumes. In mouse models of cancer, both approaches greatly increased the sensitivity of liquid biopsies.
