CXCR1 and breast cancer: The only chemokine that was released by all the non-luminal breast cancer lines, (MDA-MB-231, MDA-MB-435S and MDA 468) was interleukin-8, but blockade of the relevant receptors CXCR1 and CXCR2 with appropriate antibodies only slightly reduced the migratory activity of NG suggesting that other mediators might be involved in their activation (data not shown).