CXCR6 and cancer: Our study suggests direct roles for CXCL16-CXCR6 on prostate cancer by demonstrating co-localization of CXCL16 and CXCR6 on cancer cells, finding significant positive correlations between expression of CXCL16 and CXCR6 vs. the stage and grade of prostate cancer, and showing that CXCL16 can stimulate the growth of prostate cancer cell lines transfected to express CXCR6.