Hybrid cells, in circulation and in the tumor are reprogrammed cancer cells displaying immune cell mimicry—insights into their impact on tumor progression, immune cell interaction, and regulation of the tumor microenvironment have not yet been explored. In this study, I aim to characterize both the genotypes and phenotypes of hybrid cells in UM, drawing comparisons between hybrid cells across the metastatic cascade that will ultimately aid in our understanding of UM disease progression. Furthermore, I will evaluate RUNX1 pathway phenotypes across the metastatic cascade, as a means for facilitating hybrid cell dissemination. The study of hybrid cells in UM has great potential to uncover new biologic insights to neoplastic cell dissemination and ultimately lead to a greater understanding of targetable mechanisms of this process.