Dr. Yang is examining tumor heterogeneity in search of new diagnostic markers and potential therapeutic targets. A tumor consists of not only cancer cells, but also immune cells, fibroblasts, and other stromal components. The diverse cell types and cell states that form the tumor microenvironment (TME) may promote disease progression and lead to therapeutic resistance. Dr. Yang aims to uncover fundamental principles of tumor evolution by generating a comprehensive and quantitative “traffic map” of cancer cell state transitions and fitness changes during tumor development. Understanding this fundamental question has the potential to reveal key biomarkers that predict treatment response and actionable targets that drive resistance, thereby opening up new possibilities for long-lasting, multilayered tumor control.