HDAC1 and neoplasm: In a few number of cases, the gene upregulation was not statistically significant (including P19 for HDAC1; P17 and P19 for HDAC2, P19, P24, P25 and P26 for HDAC4) and in P17 there were no differences in the transcript level of HDAC3 between the tumor and normal colorectal tissues.