Harmonization and standardization of tumor markers and liquid biopsies in China: A short perspective

Circulating tumor markers such as serum carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), and carbohydrate antigen (CA) 15-3 are widely used. In recent years, liquid biopsies, including circulating tumor DNA and tumor mutational burden, have been developed. In this review, we describe the status of harmonization and standardization of tumor markers in clinical practice in China, based on a systematic literature search of the CNKI and PubMed databases. Substantial inter-laboratory variability in measurement results persists. Participation in national external quality assessment (EQA) schemes and proficiency testing (PT) has successfully mitigated result discrepancies across different instruments and laboratory procedures during the last decades. Further development and refinement of standardization and harmonization approaches for liquid biopsies remain an unmet need.