Blood-based Tumor Markers in Lung Cancer

In recent years, "liquid biopsy" received enormous attentionas a new detecting method. As a non-invasive tumor screening method, the applications of liquid biopsyinclude early detection, monitoring relapse, assessment of therapy and molecule expression in lung cancer. The main source of liquid biopsy comes from circulating tumor cells (CTCs), ctDNA, and so on. This review will explore the biological characteristics, detection technologies and clinical applications of CTCs, ctDNA and other tumor markers in lung cancerand summarize liquid biopsy which in accord with three important criteria of high sensitivity (highspecificity), clinical utility and repeatability, especially a new method of ligand-targeted PCR (LT-PCR) that showed a high sensitivity of 67.2% in stage I lung cancer. We expect that "liquid biopsy" could be really explored from scientific research to clinical application.