-Demethylated the CpG island in the promoter of GSTP1 in PC-3 cells-Demethylated the GSTP1 promoter in the LNCaP line-Demethylated the CpG island of the promoter of EPHB2 in the PC-3 line-Demethylated the CpG islands of the promoter of RASSF1A in the LNCaP line-Increased the nuclear expression of GSTP1 in line DU-145-Increased the expression of EPHB2 in the cytoplasm of DU-145 cells⇒ Epigenetic modifications of DNA,such as the promoter CpG island demethylation of tumor suppressor genes, might be related to the protective effect of daidzein on prostate cancer. The gene discussed is GSTP1; the disease is prostate cancer.