Cancer cells exhibit remarkable heterogeneity in cell signaling, metabolism, and other functional states. Changing environmental conditions impose additional stresses on cancer cells, further increasing tumor heterogeneity as subsets of cells reprogram key functions to survive, disseminate, and ultimately produce metastases. Tumor heterogeneity and adaptations of cancer cells emerge dynamically over the course of tumor progression and treatment, underscoring the critical need to analyze cancer cells over space and time. As an expert in molecular imaging, cancer model systems, and cancer biology, I develop approaches to quantify key processes in cancer biology, including signaling, metabolism, and pharmacodynamics of therapy, in complex living systems from cell-based assays to animal models. My expertise in fluorescence and bioluminescence imaging makes me uniquely qualified to accomplish these goals. I am a pioneer of in vivo bioluminescence imaging of biochemical events, having invented firefly luciferase complementation. I remain at the forefront of developing new bioluminescence methods for discovery in cancer. I have a strong record of engineering new reporters and implementing methods to extend capabilities of in vivo multiphoton microscopy, both with multiplexed fluorescence imaging reporters and fluorescence lifetime imaging. To capture tumor heterogeneity from imaging data, I write custom image processing code to automatically segment and quantify multiple imaging reporter signals from thousands of cells. My effort is fully funded by 3 NCI research programs. 1) Integrators of Metastatic Potential: Discover how GIV, a signaling hub for multiple signaling pathways, drives programs necessary for metastasis-initiating cells; 2) Imaging Disease Heterogeneity and Response to Therapy in Myelofibrosis: Develop novel imaging methods to analyze the bone marrow environment and pharmacodynamics of therapy in myelofibrosis and other myeloproliferative neoplasms; and 3) University of Michigan Quantitative Co-Clinical Imaging Research Resource: Establish and standardize quantitative imaging methods for co-clinical trials using established and investigational therapies for myelofibrosis. These projects are dynamic, productive multidisciplinary collaborations involving me, the Research Director (Dr. Gary Luker, MD), and a network of exceptional investigators in oncology, cancer biology, cell signaling, and imaging. My multidisciplinary expertise and experience allow me to effectively bridge the gap that may exist among scientists and trainees from disparate scientific fields. This award will enable me to continue interdisciplinary molecular imaging research focused on understanding and overcoming tumor heterogeneity to advance precision medicine in cancer.