SIRT1 expression is associated with a poor prognosis, whereas DBC1 is associated with favorable outcomes in gastric cancer

Clinical trials of histone deacetylase (HDAC) inhibitors as antitumor therapy have been conducted for gastric cancer. Expression of SIRT1, a class III HDAC, is related to poor prognosis in some malignancies. We investigated the correlation between SIRT1 expression and progression and prognosis of gastric cancers comparing with molecules linked to SIRT1 in order to better predict the efficacy of HDAC inhibitors in treating this disease. We evaluated SIRT1 expression by western blot in 51 cases and SIRT1, DBC1, acetylated H4K16 (H4K16Ac), acetylated H3K9 (H3K9Ac), and p53 by immunohistochemistry (IHC) in 557 cases of gastric cancer. Western blotting showed that SIRT1 high expression related with statistics to advanced tumor progression, positive lymphatic invasion, positive venous invasion, and advanced stage but not to poor prognosis. IHC revealed that SIRT1 high expression correlated with worse clinico-pathological prognostic factors as same as in western blotting and related poor prognosis both by univariate and multivariate analyses. By the contrast, DBC1 and H4K16Ac were related to favorable prognostic factors and linked to favorable prognosis by univariate analysis but not by multivariate analysis. H3K16Ac correlated only favorable prognostic factors. Results of p53 were very similar to those of SIRT1. We found that SIRT1 high expression closely correlates with progression and prognosis in gastric cancer patients. And it was also indicated that SIRT1 acts as an oncogene by the results of DBC1, H4K16Ac, and H3K9Ac and might be a target molecule of HDAC inhibitor treatment for gastric cancer patients.