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.