For example, CAFs generated from breast cancer brain metastasis were able to induce the migration of patient-derived tumour cells through the expression of CXCL16 and CXCL12.35 In addition, the selective upregulation of the insulin-like growth factor 2 gene IGF2 and interferon-related genes in CAFs from different breast cancer metastatic tissues compared with primary-site derived CAFs facilitated CAF-dependent tumour formation and metastasis in vivo, and immunosuppression via regulation of T cells.36 This evidence concerns the gene CXCL12 and breast cancer.