Prostate cancer cell line 22RV1 expresses high surface levels of both CD117 and ABCG2 (CD117+ABCG2+ cells). This subpopulation shows hypomethylation in ABCG2 promoter and also overexpresses stem cells markers such as Nanog, Oct4, Sox2, Nestin, and CD133. This evidence concerns the gene POU5F1 and Familial prostate cancer.