Liquid biopsy in modern medicine: advancing diagnostics from molecular insights to clinical practice

Liquid biopsy is the analysis of tumour components in bodily fluids and is increasingly considered a complementary approach to conventional diagnostics. Although tissue biopsy is the gold standard in clinical diagnostics, this approach is invasive, spatially restricted, and often difficult to perform repeatedly. Liquid biopsy is a minimally invasive approach for molecular analysis of tumours using circulating tumour DNA, cells, and extracellular vesicles, including exosomes. Although significant progress in this field has been made, a comprehensive synthesis of the biological basis, analytical methods, and clinical utility of these circulating markers still seems fragmented, with considerable methodological heterogeneity hindering standardised clinical use. This, in turn, underscores the need to understand the appropriate approach to the clinical utility of liquid biopsy. This review article is a concise and comprehensive synthesis of important liquid biopsy markers, a review of detection methods and their utility in cancer management, and an examination of the methodological limitations of this approach, including sensitivity, standardisation, and interpretation. This review article consolidates current evidence and highlights the importance of liquid biopsy and its utility for disease monitoring and precision oncology-based therapeutic decisions.