Analysis of DNA tags could advance the understanding and treatment of many cancers Cell-free DNA (cfDNA) shed into the blood was discovered in the late 1940s but with rapid advances in genomics and computational analytics in just the past few years, researchers at Georgetown Lombardi Comprehensive Cancer Center now believe that studying tags, or modifications to this type of DNA, may lead to a better understanding of how to assess, and possibly modulate, treatment approaches for cancer and other diseases. Their perspective, drawn from a review of studies to date, appears July 27 in Frontiers in Genetics. During cell death, which is a normal part of tissue regeneration, cfDNA is shed from tissue. The shed cfDNA can be isolated from a blood sample, thus providing a reading of cell death across the body in both normal and cancer cells without the need for taking invasive biopsy samples.