Drivers of oncogenesis highjack the regulatory circuitry that governs the social behavior of tissue progenitor cells, enabling their transformed derivatives to spread throughout the body and colonize vital organs. In many patients, definitive treatment of the primary cancer is followed years later by metastatic relapse. During this lag time, tumor cells that have disseminated throughout the body prior to diagnosis remain in a non-proliferative state. We study the molecular mechanisms that enable dormant metastatic cells to survive the stress of a foreign microenvironment, evade the immune system, and eventually undergo reactivation. We study these biological processes not only because they are complex and fascinating, but also because understanding their molecular basis will lead to the development of novel and more effective cancer therapies.