These study characteristics were collected for the review: title, first author, year of publication, country, study design, histology, tumor stage, method of IL-8 detection (circulating or tissue; IL-8 cut-off), number of patients (total number of patients with low IL-8 and patients with high IL-8), clinical endpoints (OS, PFS, with HR, 95% CI, P-value) follow-up, and treatments. This evidence concerns the gene CXCL8 and neoplasm.