IL-8: In a study that was looking at the role of interleukin-8 (IL-8) in prostate cancer, specifically when it has metastasized to the bones, it was found that men with prostate cancer, particularly those with bone metastases, have much greater IL-8 levels in their serum than those without bone metastases or healthy persons. This evidence concerns the gene CXCL8 and Familial prostate cancer.