The Role of Circulating Tumor Cells as a Liquid Biopsy for Cancer: Advances, Biology, Technical Challenges, and Clinical Relevance

Simple Summary This review article explores the forefront of research and technology in the detection and isolation of circulating tumor cells (CTCs) for liquid biopsy applications. Traditional biopsies, which necessitate tissue samples, are invasive and often challenging for patients. In contrast, liquid biopsies provide a less invasive alternative, enabling the continuous monitoring of the cancer's progression and the effectiveness of treatments. Recent advancements have significantly enhanced our understanding of CTCs, underscoring their critical role in cancer research and patient management. This article aims to highlight these technological innovations and their potential to transform cancer diagnosis, prognosis, and personalized therapy, offering new hope for improved patient outcomes in the fight against cancer.Abstract Cancer remains a leading cause of mortality worldwide, with metastasis significantly contributing to its lethality. The metastatic spread of tumor cells, primarily through the bloodstream, underscores the importance of circulating tumor cells (CTCs) in oncological research. As a critical component of liquid biopsies, CTCs offer a non-invasive and dynamic window into tumor biology, providing invaluable insights into cancer dissemination, disease progression, and response to treatment. This review article delves into the recent advancements in CTC research, highlighting their emerging role as a biomarker in various cancer types. We explore the latest technologies and methods for CTC isolation and detection, alongside novel approaches to characterizing their biology through genomics, transcriptomics, proteomics, and epigenetic profiling. Additionally, we examine the clinical implementation of these findings, assessing how CTCs are transforming the landscape of cancer diagnosis, prognosis, and management. By offering a comprehensive overview of current developments and potential future directions, this review underscores the significance of CTCs in enhancing our understanding of cancer and in shaping personalized therapeutic strategies, particularly for patients with metastatic disease.