A review on Liquid Biopsy Technologies and its Applications

Abstract

Early cancer diagnosis remains a major clinical challenge, as imaging lacks molecular resolution and tissue biopsy is invasive, slow, and poorly suited to repeated sampling. Liquid biopsy (LB), the analysis of tumor-derived components in blood, urine, saliva, and other body fluids, has emerged as a minimally invasive alternative that can capture the molecular profile of a tumor, often before symptoms appear. This review outlines the key LB biomarkers, including circulating tumor cells, circulating tumor DNA, tumor-derived extracellular vesicles, circulating tumor RNA, and tumor-educated platelets, and explains how tumors release these traces into circulation. It then examines the technologies driving the field: next-generation sequencing, PCR-based methods, multi-omics integration, artificial intelligence, microfluidics and lab-on-chip systems, nanotechnology, and digital pathology. Clinical applications are discussed for lung, breast, colorectal, pancreatic, and prostate cancers, along with uses beyond detection, such as real-time treatment monitoring, minimal residual disease assessment, recurrence prediction, and companion diagnostics. The review also considers the commercial and pharmaceutical landscape, including diagnostic developers, investment trends, and the role of LB in drug development. Finally, it addresses the barriers to routine adoption, namely sensitivity and specificity limits, false results, lack of standardization, regulatory pathways, and cost, and looks ahead to the convergence of AI, genomics, and diagnostics in predictive, personalized oncology.