AbstractRecent advances in cancer biology and the development of new research tools have enabled interrogations of single cells and cell–cell interactions. Emerging technologies are capable of revealing data on the physical characteristics of cells, differences in the genome and proteome between cancerous and healthy cells, and variations in distinct cell subpopulations. Dynamic measurements enable studies that can reveal the evolution of cell characteristics. Cells can also be assembled in vitro or ex vivo into two- and three-dimensional cell environments, allowing for studies of cell–cell interactions and cell signaling. The Memorial Sloan Kettering Cancer Center, in collaboration with the Breast Cancer Research Foundation and the National Cancer Institute, co-organized a workshop as an opportunity for leading researchers in their respective fields to present and discuss scientific research highlights relevant to the utilization of techniques and technologies for studying cell-to-cell communications in cancer. Avenues of future development and the potential for clinical utility were primary features of these discussions. The scientific presentations and extensive ensuing discussions resulted in the identification of a number of research opportunities, which are summarized in this report.