Abstract 79: Role of histone deacetylase expression in intrahepatic cholangiocarcinoma

<jats:title>Abstract</jats:title> <jats:p>Introduction: Histone deacetylase (HDAC) plays an important role in chromatin remodeling, gene expression and in regulating cell cycle progression and differentiation. Furthermore, HDAC inhibitors have recently been found to repress the function of hypoxia inducible factors (HIF) through inducing hyperacetylation of histones. However, few studies have been conducted regarding the role of HDAC in IHCC. The aim of this study was to elucidate the role of HDAC in IHCC.</jats:p> <jats:p>Methods: Thirty-five patients with IHCC who underwent hepatic resection were evaluated. The expressions of HDAC1 and HIF-1α were determined immunohistochemically, and the patients were divided into two groups: HDAC1 positive group (n=21); and HDAC1 negative group (n=14). Clinicopathological variables including HIF-1α expression were compared between the two groups.</jats:p> <jats:p>Results: The HDAC1 expression correlated significantly with higher stage carcinoma, lymph node metastasis, and vascular invasion. The prognosis in the HDAC1 positive group was poorer than in the HDAC1 negative group (5-year survival: 77.9% vs. 7.9%, p=0.001). In the multivariate analysis, HDAC1 positive expression was identified as the only independent prognostic factor for disease free survival (Hazard Ratio: 7.194, p=0.0018). Furthermore, there was a significant correlation between HDAC1 expression and HIF-1α expression (p=0.007), and co-expressions of these markers in same cancer cells were proven by immunofluorescent stainings in the serial section</jats:p> <jats:p>Conclusions: The findings suggested that a positive expression of HDAC1 is a new prognostic indicator of IHCC, and that HDAC1 might be a possible promising molecular target of IHCC, through the regulation of HIF-1α.</jats:p> <jats:p>Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 79. doi:10.1158/1538-7445.AM2011-79</jats:p>