HDAC4 and bladder transitional cell carcinoma: The results obtained from our immunohistochemistry (IHC) staining studies further revealed a strong correlation between the over-expression of HDAC4 and the occurrence of bladder transitional cell carcinomas (p < 0.001) as well as a marginal significance between the over-expression of HDAC4 and the severity of the bladder tumors (p = 0.08).