CXCL12, the ligand of CXCR4, which is secreted from activated fibroblasts, was proven to stimulate cancer cell migration and promote cancer cell invasion through EMT transition [17, 25, 42], and is also elevated in CAF1 compared to NF1/NF2 (Supplemental Fig. S5b). This evidence concerns the gene CXCL12 and cancer.