CCL2 and breast cancer: Yao et al. used the human MCF10CA1d xenograft model (basal-like BC) and found that the growth of primary tumors was significantly increased by cotransplantation of fibroblasts derived from BC patients expressing high levels of CCL2, which was inhibited by mutation of the CCL2 gene in fibroblasts by CRISPR‒Cas9 technology.