Abstract: Cancer is one of the main factors threatening human life. Compared with the commonly used tissue biopsy technology, liquid biopsy, as a detection method of cancer, has many significant advantages, such as non-invasive, high accuracy, simple sampling
and low price. Liquid biopsy has great potential in early detection, dynamic monitoring and targeted treatment of various cancers,
including lung cancer, cervical cancer and prostate cancer. It provides a new technical means and research ideas for cancer detection and treatment. In liquid biopsy, circulating tumor DNA (ctDNA), circulating tumor cell (CTC) and exosomes are often used as markers to detect the course of cancer. Based on the techniques commonly used in life science research such as PCR, NGS and ELISA, a variety of indicators are used as the basis to judge the course of cancer. In this paper, the detection principle of ctDNA, CTC and exosomes as liquid biopsy markers and their recent research progress in clinical application are reviewed.