Clinical Application of Peripheral Blood Biomarkers for Solid Tumors

The growing emphasis on precision medicine in the management of solid tumors has underscored the limitations of traditional diagnostic approaches, which often lack sufficient sensitivity or rely on invasive procedures. In contrast, peripheral blood biomarkers provide a minimally invasive, dynamic, and potentially more accurate means for cancer detection and monitoring. The enhancement of detection technology has enabled the incorporation of an increasing number of biomarkers into exploratory clinical trials, which, in turn, have demonstrated immense clinical utility. However, numerous hurdles remain before these biomarkers can be applied in a real clinical setting. This review comprehensively summarizes the clinical utility of key blood-based biomarkers, including circulating tumor cells, circulating tumor DNA, extracellular vesicles, cell-free RNA, peripheral blood mononuclear cells, and proteins. We discuss their biological characteristics, detection methodologies, and recent advances in their clinical applications. Moreover, we highlight the emerging role of new technologies such as artificial intelligence (AI) in decoding complex data and facilitating clinical decision-making. It is expected to establish the overarching concept of the blood biomarker panel and to understand its comparative advantages, which are essential to realize its potential in precision oncology.