CXCL9 and breast cancer: In order to validate the overexpression of IFN-γ and IFN-γ inducible chemokines known to be involved in tumor progression and metastasis [26], expressional levels of the CXCR3/CXCL9, CXCL10, CXCL11 axis were scrutinized in ER-breast cancer samples of women with metastatic disease, with or without brain seeding.