Biomarker signals in exosomes and extracellular vesicles are fundamentally different from cell free DNA (cfDNA) and circulating tumor cells (CTCs) in their origin and biogenesis. Cell free DNA or circulating tumor DNA is from dying cells. Circulating tumor cells are entire living cells that are shed from a tumor once the tumor reaches a certain stage in its development. In contrast, exosome generation is an active metabolic process that happens in all living cells in the body including normal healthy cells, making exosomes a rich source of biomarkers from living growing cells. Therefore, exosome analysis can provide insight into earlier stages of cancer growth as well as in non-cancer diseases or conditions, where no cell death is occurring and minimal amounts of cfDNA or CTCs are present.