Metastasis is the leading cause of death in cancer patients and remains the most difficult stage of cancer to treat. Understanding the molecular mechanisms that drive metastasis will lead to rational therapies that specifically target these cancers. Research in the Stewart Laboratory involves identifying novel genes and signaling pathways that regulate cell migration during embryonic development and translating these findings to animal models of cancer to determine if these mechanisms are “reactivated” in metastasis. We use zebrafish in our studies because the forward genetic capacity and exceptional imaging qualities of zebrafish embryos and adult pigment mutants allow us to identify new genes and pathways controlling cell migration and metastasis in vivo using real-time imaging techniques. In addition, the molecular pathways underlying mammalian embryonic development and cancer are highly conserved in zebrafish. Thus, the attributes of the zebrafish system provide a unique opportunity to determine how developmental mechanisms controlling cell migration during development are subverted in pediatric diseases and cancer metastasis.