From Blood to Biomarkers: Liquid Biopsy as a Tool in Precision Oncology

Abstract

Precision oncology relies on accurate, timely, and minimally invasive approaches to detect and monitor cancer. Traditional tissue biopsies are invasive and often fail to capture tumour heterogeneity or allow repeated sampling. Liquid biopsy has emerged as a promising alternative in precision oncology, enabling the analysis of tumour-derived biomarkers circulating in the body fluids. This review synthesises current knowledge on the biological basis, technological platforms, and clinical applications of liquid biopsy. Key circulating biomarkers—including circulating tumour DNA (ctDNA), circulating tumour cells (CTCs), circulating RNA, extracellular vesicles (EVs), and tumour-educated platelets (TEPs)—are examined in the context of cancer diagnosis, prognosis, and therapeutic monitoring. A liquid biopsy, therefore, enables the real-time assessment of tumour dynamics, early detection of therapy resistance, and evaluation of minimal residual disease. Advances in technologies such as next-generation sequencing, digital PCR, and microfluidic CTC capture have improved sensitivity and specificity, allowing detection of low-abundance biomarkers. Evidence suggests that liquid biopsy can complement conventional diagnostics, provide a comprehensive view of tumour heterogeneity, and facilitate personalised management and treatment strategies. This approach represents a minimally invasive, dynamic, and clinically informative platform in precision oncology. While challenges remain—such as standardisation, sensitivity, and cost—its integration into routine clinical practice has the potential to revolutionize cancer diagnosis, monitoring, and treatment personalisation.