CCL21 and prostate cancer: Cancer vaccines have demonstrated promising therapeutic effects and several are in late-stage clinical trials, including the WT1-targeted DC vaccine, breast cancer-Her2 pulsed DC vaccine 36, GVAX for patients with hormone-naïve prostate cancer and prostate-specific antigen relapse, PROSTVAC for prostate cancer 8, 34, and the lung cancer-CCL21 DC vaccine 36.