We observed that inhibition of CXCR4 by the small molecule antagonist AMD3100 or blockage of CXCR4/CXCL12 interaction by a neutralizing anti-CXCR4 antibody could specifically inhibits proliferation of prostate progenitor population in PC3 and DU145 prostate cancer cell lines in vitro and in vivo and may provide a new approach to deplete prostate cancer stem cells. The gene discussed is CXCL12; the disease is prostate carcinoma.