CXCL5 and prostate cancer: C-X-C motif ligand (CXCL)5 secreted from prostate cancer cells attracts MDSCs expressing C-X-C chemokine receptor (CXCR)2, and the elimination of MDSCs or the blocking of CXCL5-CXCR2 signaling elicits antitumor responses in the Pten/Smad4-deficient mouse model [69].