Chen et al. determined that CAFs isolated from samples of patients with invasive ductal carcinoma were capable of transferring exosomal miR-500a-5p to breast cancer cell lines, this miRNA bound to ubiquitin-specific peptidase 28 (USP28) promoting cell proliferation and metastasis in a nude mouse xenograft model (Chen et al., 2021). Here, USP28 is linked to breast cancer.