The Selected Cell Epigenomic Analysis Core supports PC-OC projects by enabling molecular analysis (e.g, RNA profiling or assessment of epigenomic patterns) that reach beyond the ensemble measurements that conventionally limit studies derived from composite averages over large numbers of cells and molecules. We harness and advance the technologies derived from engineering and physical science to isolate and observe selected cells and their interaction with and response to environmental factors. Each PC-OC project will identify and characterize particular tumor cell phenotypes. For example, CTC subpopulations that can adhere to endothelium, tumor cells that effectively migrate through 3D matrix scaffolds and those that effectively recruit new vascular beds will all be identified. Yet, these capabilities reside in rare subpopulations. The Core will develop processes and devices to rapidly evaluate the molecular state of a few selected cells and work toward analysis of individual cells. The Core will enable PC-OC scientists to understand the distribution of properties and to then consider the consequences of this heterogeneity in the context of various microenvironments. Such analyses should lead to a more fundamental understanding of cancer.