Potential Prognostic Value of Histone Deacetylase 6 (HDAC6) Combined with Heat Shock Protein 90 (HSP90) in Breast Cancer

Abstract

Introduction: Histone deacetylase6 (HDAC6) is known as a deacetylase of HSP90 (heat shock protein 90). Many studies have investigated the role of HDAC6 in tumorigenesis and its association with the prognosis of cancer patients. This study aimed to evaluate the prognostic value of HDAC6 and acetylated HSP90 in the cohort of breast cancer patients. Materials & Methods: The surgical specimens of 291 patients with invasive breast cancer were stained immunohistochemically to assess the expression of HDAC6 and acetylated HSP90 level in addition to the standard pathologic factors. Statistical analyses were performed to evaluate the association of HDAC6, HSP90, and other clinico-pathologic factors, and to find the prognostic values of these factors. Results: HDAC6 expression and acetylated HSP90 level correlated with HER-2 (human epidermal growth factor receptor-2) amplification. HDAC6 expression correlated with acetylated HSP90 level in the entire patient group (p=0.007). In subgroup analysis, correlation between HDAC6 and acetylated HSP90 level was significant in the HER-2 negative patients (p=0.009), but not in the HER-2 positive patients. HDAC6 expression correlated with acetylated HSP90 level in the ER (estrogen receptor) positive group (p=0.022), but not in the ER negative group. High expression of HDAC6 combined with low acetylated HSP90 level showed the tendency for poorer disease-free survival in the ER positive patients group (p=0.066). Conclusions: HDAC6 expression and acetylated HSP90 level correlated with each other. High expression of HDAC6 combined with low acetylated HSP90 level had marginal prognostic value for predicting poorer disease-free survival within the ER positive patients group.