Genomic sequencing studies have revealed a surprisingly high burden of cancer driver mutations in healthy human organs, showing that the presence of mutant cells could be tolerated without perturbing normal physiological functions. Mechanisms mediating this resilience against cancer remain poorly understood. Studies in model organisms have shown that the growth of mutant cells can be restrained by competition with neighboring normal cells. However, it is unclear what factors are regulating this competition and how some mutant cells manage to outcompete normal cells and lead to cancer. Siqi Li will use novel genetic methods to identify intercellular signaling processes coordinating the behavior of mutant and normal cells and investigate how these processes may be targeted to suppress early cancer development. These studies will increase our knowledge of the earliest stage of cancer formation and potentially open up new opportunities for cancer prevention.