Expression of HDAC9 in gastric cancer and its clinical significance

Our experiments mainly studied the expression of HDAC9 and the clinical index of gastric cancer patients. The data showed that HDAC9 was localized in the nucleus. The expression was significantly increased in cancer tissues compared to para-carcinoma tissues (73.25% +/- 23.01% VS 59.74% +/- 22.61%, P=0.000) with no correlation of each other (P=0.672). At the same time, we also found that the expression of ki67 was positively correlated with HDAC9 in gastric cancer tissues (r=0.404, P=0.000). Subsequently clinical parameters correlation analysis confirmed that HDAC9 expression in cancer tissues was not significantly correlated with any clinical factor (P>0.050), while HDAC9 expression in adjacent tissues was negatively correlated with M staging (r=-0.223, P=0.048). Survival analysis revealed that HDAC9 expression in cancer tissues was not associated with the prognosis (P=0.835), while HDAC9 expression in para-carcinoma tissues showed significant correlation with the survival time (P=0.002) and was the only independent prognostic factor (P=0.002). Thus, we speculated that HDAC9 may act two completely different biological functions in cancer tissues and adjacent tissues through different gene networks, respectively. The expression of HDAC9 in gastric cancer tissues might promote cell proliferation, thus could indirectly reduce the patients' prognosis. While the expression of HDAC9 in para-carcinoma tissues could prevent tumor cell from distant metastasizing, then improved the prognosis of patients directly. Further studies were needed to investigate HDAC9 signaling networks in gastric cancer cells, normal gastric epithelial cells and metaplastic cells.