Abstract
Advances in deep sequencing technology have led to developments in personalized medicine. Here, we describe the implications of a recent investigation that sequenced ctDNA from the plasma of non-small cell lung cancer patients to develop personalized ctDNA tests. These 'liquid biopsies' have shown promise in monitoring tumor growth and response to treatment, providing a timely overview of mutations present in the tumor. We discuss the advantages of this budding approach, as well as its challenges and drawbacks, while also providing areas for further investigation and an outlook for the future.