Abstract All cells in the body, including tumor cells, release small vesicles that can be found in blood, cerebrospinal fluid, and even urine. Because each vesicle was released by a specific cell, their analysis can tell us about the cells from which they came, including whether that cell was infected, cancerous, or malfunctioning in some way. We will develop assays and kits to enable cancer researchers to analyze these vesicles to improve the ability to understand, detect and treat cancer.