Liquid Biopsy and ctDNA

Liquid biopsy and circulating tumor DNA (ctDNA) testing are reshaping how cancer can be profiled, monitored, and followed through a blood sample. This category explores how cell-free DNA, ctDNA, circulating tumor cells, mutation panels, and tumor-fraction testing can reveal cancer-related genomic changes without relying solely on tissue biopsy. Topics include minimal residual disease (MRD), recurrence detection, treatment-response monitoring, and tumor-informed versus tumor-naive testing. Detailed guides cover clinically important mutations such as KRAS, EGFR T790M, and ESR1, along with resistance markers that may influence targeted therapy decisions. You’ll also find practical explanations of tests and platforms including Signatera, RaDaR, Guardant360, FoundationOne Liquid CDx, Tempus xF, and OncoBEAM. The collection also examines emerging approaches to blood-based cancer detection, including multi-cancer early detection tests, Galleri, CancerSEEK, fragmentomics, exosomes, and other circulating biomarkers. Each topic focuses on what the test measures, how results are interpreted, important limitations, false-negative risks, and where liquid biopsy may fit alongside tissue testing and standard cancer surveillance.