HDACs, which are frequently upregulated in PCa, remove the acetyl groups from lysines on the histones.[90] The expression levels of HDAC mRNA and proteins are increased up to 3-folds in PCa as compared with BPH tissues and cell lines.[91] The highest levels of HDAC1 are detected in hormone refractory PCa which supports a role for this epigenetic modification in androgen-independent PCa.[92] Histone methylation on a specific location of the histone tail is another type of histone modification. The gene discussed is HDAC9; the disease is posterior cortical atrophy.