Using a parallel approach in murine mammary cancers, we found that ROCK activation in cancer cells induces the production and secretion by these cells of Cysteine‐rich with EGF‐like domains 2 (Creld2), which acts on tumor fibroblasts, converting them to a tumor‐promoting form of CAFs and promoting mammary tumor progression (Boyle et al., 2020). The gene discussed is CRELD2; the disease is cancer.