Liquid biopsy in breast cancer management: From circulating biomarkers to clinical breakthroughs.

Breast cancer continues to be a major global health concern, particularly for women, despite improvements in early detection and treatment strategies. Traditional tissue biopsies have long been the foundation of diagnosis and treatment planning; however, they come with limitations-such as being invasive, providing only a single snapshot of a dynamic disease, and often missing the evolving molecular landscape, especially in metastatic cases. In recent years, liquid biopsy has emerged as a powerful, noninvasive tool offering real-time insights into tumor biology. By analyzing materials shed by tumors into the bloodstream-such as circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), exosomes, and cell-free RNA (cfRNA)-liquid biopsy can reveal changes in tumor burden, treatment response, and the appearance of drug resistance. These advantages make it especially valuable in personalizing care for breast cancer patients across various subtypes, including hormone receptor-positive, HER2-positive, and triple-negative breast cancer. This review highlights the components and technological platforms that underpin liquid biopsy, explores its current clinical applications, and discusses future directions, including integration with artificial intelligence and multi-omics analysis. As research advances and clinical evidence grows, liquid biopsy holds the promise of reshaping breast cancer care, making it more precise, timely, and individualized.