Liquid Biopsy in Solid Tumours: An Overview

Abstract

The advent of personalised and precision medicine has radically modified the management and the clinical outcome of cancer patients. However, the expanding number of predictive, prognostic, and diagnostic biomarkers has raised the need for simple, noninvasive, quicker, but equally efficient tests for molecular profiling. In this complex scenario, the adoption of liquid biopsy, particularly circulating tumour DNA (ctDNA), has been a real godsend for many cancer patients who would otherwise have been denied the benefits of targeted treatments. Undeniably, ctDNA analysis has several advantages over conventional tissue-based analysis. One advantage is that it can guide treatment decision making, especially when tissue samples are scarce or totally unavailable. Indeed, a simple blood test can inform clinicians on patients' response or resistance to targeted therapies, help them monitor minimal residual disease (MRD) after surgical resections, and facilitate them with early cancer detection and interception. Finally, an equally important advantage is that ctDNA analysis can help decipher temporal and spatial tumour heterogeneity, a mechanism highly responsible for therapeutic resistance. In this review, we gathered and analysed current evidence on the clinical usefulness of ctDNA analysis in solid tumours.

Keywords: NGS; ctDNA; liquid biopsy; molecular oncology; molecular pathology.

FIGURE 1

Daily practice adoption of ctDNA in solid tumours. This figure was created with BioRender (https://biorender.com) (accessed on 03 January 2025). ALK, Anaplastic Lymphoma Kinase; BRAF, V‐Raf Murine Sarcoma Viral Oncogene Homologue B1; CRC, colo‐rectal cancer; ctDNA, circulating tumour DNA; EGFR, Epidermal Growth Factor Receptor; ESR1, Oestrogen Receptor 1; HER2, Human Epidermal Growth Factor Receptor 2; HR, hormone receptor; HRD, homologous recombination deficiency; KRAS, Kirsten Rat Sarcoma Viral Oncogene Homologue; MET, MET Proto‐Oncogene, Receptor Tyrosine Kinase; NSCLC, non‐small cell lung cancer; PIK3CA, Phosphatidylinositol‐4,5‐Bisphosphate 3‐Kinase Catalytic Subunit Alpha; ROS1, ROS Proto‐Oncogene 1 Receptor Tyrosine Kinase; RET, REarranged during Transfection; SEPT9, septin9.