As CAF-S1 attract cancer cell at distance and secrete high levels of CXCL12 (Supplementary Fig. 5a), we first analyzed the impact of CXCL12 silencing in CAF-S1 and CAF-S4 (Supplementary Fig. 5b) on BC cell proliferation and migration. The gene discussed is CXCL12; the disease is breast cancer.