PROJECT SUMMARY This is a new application for a Ruth L. Kirschstein National Research Service Award Institutional Research Training Grant (T32) to train post-doctoral trainees in the field of oncopathology, defined broadly as research that seeks to improve our understanding of cancer pathogenesis and pathobiology, and in doing so provide the basis for the development of new approaches that improve cancer diagnosis, prognostication, and treatment. The overall goal of the Oncopathology Training Program (OTP) is to provide research training opportunities across the full spectrum of oncopathology research, from basic study of cancer pathogenesis using the tools of cell and molecular biology, genomics, proteomics, animal modeling, and bioinformatics, to translational research that involves the development and deployment of biomarker tests and the use of digital and computational pathology, approaches that are increasingly important in cancer research. The training program is designed to benefit the research career development of M.D. and M.D./Ph.D. trainees subsequent to their training in clinical and/or anatomic pathology, and Ph.D. trainees with educational backgrounds in computational fields interested in the emerging area of computational pathology. Support is requested for 4 postdoctoral trainees in years 1-2, and 5 trainees in years 3-5. The training program includes structured elements such as individual development plans, mentored research experiences, and customizable didactic training opportunities as well as workshops in grant writing, manuscript composition, and lab management. Each trainee will have Postdoctoral Advisory Committee comprised of the Program Director, primary research mentor, and one or more senior cancer researchers with relevant expertise that will review trainee progress, provide advice and constructive criticism, and serve as a review committee for external fellowship proposals. The OTP faculty includes 24 highly accomplished investigators, with extensive mentoring track records and substantial extramural grant support, who constitute a highly collaborative mentoring community whose expertise span a wide-range of multidisciplinary, oncopathology-relevant areas, including animal modeling of cancer, cancer immunology, cancer genomics, computational pathology and tissue imaging, cancer diagnostics, and translational cancer informatics. The OTP will also take advantage of the extensive complement of scientific and educational resources that are available at Brigham and Women’s Hospital (BWH), Harvard Medical School (HMS). and Dana Farber Cancer Institute (DFCI), including the NCI-funded Dana-Farber/Harvard Cancer Center.