For over a century, scientists have known that tumors shed molecules and cells into bodily fluids, and recent advancements revealed that analyzing these molecules and cells can yield similar information to that of tissue biopsies, paving the way for less invasive approaches in clinical applications. Liquid biopsy involves the identification and analysis of cell-free DNA (cfDNA) derived from bodily fluids like blood, urine, cerebrospinal fluid, or saliva. These free-floating, naked DNA molecules are actively shed into circulation by live cells, as well as by cells undergoing death by apoptosis and/or necrosis. For the oncology patient, circulating tumor DNA (ctDNA) shed from cancer cells may provide diagnostic and prognostic clues to optimize care.
