CXCL8 and breast cancer: Elevated levels of the alpha chemokine IL-8 are associated with the increased bone metastasis and osteolysis of human breast cancer cells.(3,32,33) IL-8 is a heparan sulfate–binding osteoclastogenic factor and as such could cooperate with the heparan sulfate chains on the syndecan-1 shed by the HPSE-High cells.