Cancer is a scourge on the face of humanity, responsible for over 550,000 deaths in 2008 in the US, one out of every four. New diagnoses this year will top 1.4 million, with projections only growing as the population ages. From a global health perspective, the vast majority of cancer deaths occur in low and middle income countries, and the incidence and death rate is rising in these countries, adding to our urgency to improve prevention and treatment. The promise of nanotechnology in cancer lies in the ability to engineer customizable nanoscale constructs that can be loaded with one or more payloads such as chemotherapeutics, targeting units, imaging and diagnostic agents. Nanotechnology holds great promise for cancer, with the potential to address many difficult problems now facing cancer prevention, diagnosis, and therapy. These include the application of nanotechnology to early detection/cancer prevention, through identification of rare circulating tumor cells. Proteomics in particular is emerging as a tool for detection of nuclear matrix proteins and new biomarkers for screening of early tumors stage. Nanowires and nanocantilever arrays are among the leading approaches under development for the early detection of precancerous and malignant lesions from biological fluids. Nanobiotechnologies have been applied to improve drug delivery and to overcome some of the problems of drug delivery in cancer. Enhancing the activity and specificity of radiation therapy by sensitization of tumor tissues to radiation through nanoparticle targeting of tumor tissue is an approach currently in clinical testing. Nanoparticles are also being used for gene therapy for cancer. Targeting of the tumor environment, rather than the tumor itself, could be facilitated by nanoparticle-mediated gene delivery to tumor neovasculature. With potential advances in therapy garnered through nanotechnology, significant improvements in tumor imaging will be required for their effective application. New technology allowing sensitive detection of residual disease, and molecular characterization of these minimal residual cancer cells in patients with solid tumors, will be critical in determining the length of a course of treatment, saving the patient potential toxicity and expense. In the proposed training center proposal, we endeavor to do just that, directly couple faculty and students from physical and biological sciences on our Charles River Campus with the medical researchers and clinicians on our Medical Campus. Our program creates mechanisms for connections between the campuses with co-mentoring, cross-fertilized research projects, and interdisciplinary courses and workshops, easily overcoming the simple physical barrier of a mile of asphalt, and leading participants on the way to surmount the more challenging scientific cultural and disciplinary barriers.