Blocking CXCR4 and/or CXCL16 neutralization, alone or in combination, resulted in significant inhibition of patient-derived cancer cells migration to brain metastatic CAF aggregates, further supporting the importance of CXCL16 and CXCL12 in migration of CTCs into brain-associated microenvironment. The gene discussed is CXCL16; the disease is cancer.