Erasing iatrogenic neoantigens from in vivo CRISPR screens.

In vivo genetic screens using CRISPR-Cas9 are a powerful tool to resolve the molecular determinants of response and resistance to cancer immunotherapies; however, vector immunogenicity can introduce artifact. In this issue of Immunity, Dubrot et al. report a strategy to "erase" vector-associated neoantigens, enabling a more physiologic assessment of tumor-immune cell interactions in immunocompetent hosts.