To further investigate whether histone modification might be involved in MDR1 silencing in PCa, we compared histone active marks (H3Ac, H3K4me2, H3K4me3, H3K9Ac and H4Ac) at the MDR1 gene promoter, after exposure to TSA alone or in combination with DAC, compared to untreated cells. This evidence concerns the gene ABCB1 and posterior cortical atrophy.