Expression profile of histone deacetylase 1 in gastric cancer tissues

Although histone deacetylases (HDACs) appear to play a crucial role in carcinogenesis, the expression status of HDACs in primary human cancer tissues has not yet been reported. In this study, we investigated the expression level of HDAC1 in 25 paired primary human gastric cancer (GC) tissues and corresponding normal tissues through semi-quantitative RT-PCR and immunoblot analysis. The HDAC1 expression pattern was also topologically examined through immunohistochemistry. Overexpression of HDAC1 mRNA was detected in 68% of GC tissues (17 of 25), and the relative density of HDAC1 mRNA in GC tissue was increased 1.8-fold versus the normal counterpart (P < 0.01). Elevated expression of HDAC1 protein was also detected in 61% of GC samples (11 of 18), which also showed an increased mRNA level of HDAC. Immunohistochemically, overexpression of HDAC1 was predominantly localized in the nuclei of most neoplastic cells, including embolic tumor cells, whereas normal glandular epithelial cells revealed only weak HDAC1 expression that was focal in distribution. Thus, the present study clearly demonstrates that HDAC1 is overexpressed in GC and probably plays a significant role in gastric carcinogenesis.