Tumors are composed of heterogeneous populations of cells that possess distinct genetic, morphological, and phenotypic profiles, which in turn can impact tumor development, treatment response, and therapeutic resistance. Additionally, even tumors with similar profiles may react differently depending on their microenvironment. This conference will bring together the top basic, translational, and clinical researchers in the field of tumor heterogeneity. Presentations will feature the most recent research on basic biological mechanisms, new technological and computational developments, approaches to targeting and monitoring heterogeneity, and the implications of these findings for the clinical setting.