It is seldom the initial cancer that kills the patient; most deaths are due to its metastatic spread throughout the body. Survival after the onset of a brain metastasis is dismal. Current understanding of cancer spread to the brain is poor and yet an ability to inhibit this process would save thousands of lives each year. Using rare tissue resources and cutting-edge technologies, this project will elucidate molecular features of brain metastases that can be exploited to generate new treatments.