Table 5 Comparison of different liquid biopsy markers
From: Liquid biopsy in cancer: current status, challenges and future prospects
Form | ctDNA | CTCs | Exosome |
|---|---|---|---|
source | Blood, urine, saliva, synovial fluid, cerebrospinal fluid, etc. | Blood, cerebrospinal fluid, urine, etc. | Blood, urine, cerebrospinal fluid, ascites, pleural fluid, etc. |
scale | Nanoscale (DNA fragments) | cellular level | Nanoscale (40–150 nm) |
information load | Can carry information on multiple genetic variants | Complete genetic information, including genome, transcriptome, epigenetic variation | Carrying proteins, RNA and many other biomolecules |
clinical significance | Early screening, companion diagnosis, prognostic assessment, MRD testing | Prognostic assessment, drug sensitivity prediction, drug resistance mechanism studies | Early diagnosis, prognostic assessment, drug response monitoring |
stability | Relatively low (short half-life) | high | High (phospholipid bilayer protection) |
rarity | High (especially in early-stage tumors) | high | moderate (interference from other vesicles in body fluids) |
heterogeneity | low | High (large variation between CTCs) | moderate |
Difficulty of isolation and purification | moderate | High (not yet standardized) | High (technically complex) |
background noise | Moderate (normal cfDNA interference) | low | Moderate (interference from other vesicles in body fluids) |
Difficulty of standardization | moderate | high | high |
technical difficulty | Moderate (relies on high-sensitivity detection technology) | High (complex enrichment, identification techniques) | Medium (dependent on specific detection techniques) |
operating difficulty | low | High (multi-step operation) | moderate |
