Chen et al. found that basal-like BC cells utilize CDC42 to inhibit Casitas B-lineage lymphoma (c-Cbl)-mediated ubiquitinoylation of target proteins to be degraded in the Redox/Fyn/c-Cbl (RFC) pathway and inhibition of CDC42 restores the RFC pathway function and increases tamoxifen sensitivity in basal-like BC cells [91]. Here, CDC42 is linked to breast cancer.