Highly expressed in PC, class I HDAC expression in prostate tissue; HDAC1 and HDAC2 positively correlate with Gleason score (HDAC1, p = 0.006; HDAC2, p = 0.047; HDAC3, p = 0.584) and Ki-67 proliferative index. The gene discussed is HDAC9; the disease is pachyonychia congenita.