Tumor heterogeneity is a hallmark of cancer and a fundamental determinant of patient outcomes, and early detection has proven the most successful strategy to improve cancer outcomes. Dr. Alizadeh’s research group uses genomic approaches to decrypt this tumor heterogeneity and for improving early cancer detection, with a focus on methodological innovation. In this effort, his group made early foundational contributions to cancer taxonomy through genome-wide expression profiling, discovering important lymphoma subtypes. Building on this work, his group creates tools for detection and profiling of cancer genomic heterogeneity, and the dynamic immune microenvironment that can support or suppress tumors. The Alizadeh group helped develop innovative methods for noninvasive detection and monitoring through the profiling of circulating nucleic acids, and through the characterization of infiltrating immune cells. These methods are increasingly relevant in this exciting era of evolving targeted and immunologically directed cancer therapies.