COP1 and neoplasm: For example, for triple-negative breast cancer (TNBC), results of pooled in vivo CRISPR KO screens in syngeneic mouse models have demonstrated that the elimination of the E3 ubiquitin ligase Cop1 in cancer cells could lead to a reduction in the secretion of chemokines associated with macrophages, resulting in decreased infiltration of tumor macrophages.44