Abstract
The future of oncology diagnostics lies in detecting cancer before it reveals itself clinically, and liquid biopsy is emerging as the key to that future. Conventional diagnostic approaches, including imaging and tissue biopsy, often fall short in sensitivity, invasiveness, and real-time monitoring capacity. Liquid biopsy transforms this landscape by enabling the detection of tumor-derived materials such as circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), exosomes, and microRNAs in easily accessible body fluids. This innovation offers a minimally invasive, repeatable, and dynamic window into tumor evolution. Breakthroughs in next-generation sequencing (NGS), digital PCR, nanotechnology-driven biosensors, and artificial intelligence have greatly enhanced the precision, scalability, and predictive value of liquid biopsy assays. Beyond early diagnosis, these tools now underpin multi-cancer early detection (MCED) platforms and personalized treatment monitoring. However, challenges, such as low analyte concentrations, standardization gaps, and cost barriers, still limit widespread clinical integration. This paper reviews the latest technological, methodological, and translational innovations shaping the liquid biopsy frontier, emphasizing its transformative potential for early detection and precision oncology. As science progresses toward universal, non-invasive screening, liquid biopsy is poised to shift cancer diagnostics from reactive treatment to proactive prevention.