However, the role of CXCL16-CXCR6 axis is apparently not only restricted to CD8+ T lymphocytes recruitment to specific tissues, but it is also involved in the accumulation of neutrophils in the CSF during pneumococcal meningitis infection32, in the migration of brain tumor cells33, in the progression of glial tumors34 and in breast cancer-associated brain metastasis35. This evidence concerns the gene CXCR6 and breast cancer.