CXCL8 and neoplasm: On the one side, they can kill tumor cells, but on the other side, they may favor tumor growth, invasion, and progression by inducing immunosuppression and synthesis of higher levels of angiogenic factors such as VEGF, interleukin 8 (IL-8), TNF-alpha, metalloproteases, and fibroblast growth factor 1 (FGF-1) [5].