Advances in Liquid Biopsy for the Detection of Minimal Residual Disease in Hematologic and Solid Malignancies

The detection of minimal residual disease (MRD) is critical for predicting relapse and guiding therapeutic decisions in both hematologic and solid malignancies. Liquid biopsy, particularly the analysis of circulating tumor DNA (ctDNA), has emerged as a non-invasive and highly sensitive tool for MRD monitoring. This review explores recent advances in liquid biopsy technologies, including digital PCR, next-generation sequencing (NGS), and methylation-based assays, which enhance the detection of low-abundance ctDNA. We discuss the clinical utility of these methods in various cancers, their integration with traditional imaging and tissue biopsies, and challenges such as assay standardization and tumor heterogeneity. The review concludes with future directions, emphasizing multi-analyte approaches and artificial intelligence to improve MRD detection and personalize cancer management.