With the aim to improve the knowledge on IL-8 inhibitors and on their possible use as anti-cancer drugs for breast metastasis, in this study the effects of reparixin, a clinical grade CXCR1/2 inhibitor, administered alone or in combination with paclitaxel, were assayed in vitro on purified mammary tumorspheres from MDA-MB231 cell line and in vivo in a model of breast metastasis to brain, utilizing two different experimental conditions. The gene discussed is CXCL8; the disease is cancer.