The invention provides a method for inhibiting the aberrant growth of cells in a prostate tissue in an individual comprising administering to the individual an amount of an inhibitor of the Breast Cancer Resistance Protein (BCRP/ABCG2), where the amount of the BCRP inhibitor is effective to inhibit the growth of the aberrantly growing cells. The method is also useful for treating prostate tumors or benign prostatic hyperplasia/hypertrophy (BPH). Also disclosed is the phenotype for prostate stem cells as determined by immunohistochecmical localization methods. The prostate stem cells are positive for BCRP protein, negative for androgen receptor protein, negative for p63 protein, and negative for synaptophysin.