Demidenko R., et al. found that eight ABC transporter genes (ABCA8, ABCB1, ABCC6, ABCC9, ABCC10, ABCD2, ABCG2, and ABCG4) displayed markedly down-regulated expression in prostate cancer in comparison with nonmalignant prostate tissues, that was associated with gene promoter methylation [19]. The gene discussed is ABCG2; the disease is prostate cancer.