HDAC1 Expression in Invasive Ductal Carcinoma of the Breast and Its Value as a Good Prognostic Factor

BACKGROUND: Histone deacetylase 1 (HDAC1) is associated with the expression and function of estrogen receptors and the proliferation of tumor cells, and has been considered a very important factor in breast tumor progression and prognosis. Several studies have reported an association between HDAC1 expression and poorer prognosis in cancers including breast cancer, with a few exceptions. However, because of the dearth of studies on HDAC1 expression in breast cancer, its significance for breast cancer prognosis has not been well defined. Therefore, we examined HDAC1 expression in invasive ductal carcinoma (IDC), the most common breast cancer, and investigated its potential prognostic significance. METHODS: We used 203 IDC tissue samples. Immunohistochemical stains for HDAC1 and real-time polymerase chain reaction for HDAC1 mRNA were performed and the results were compared to generally well-established prognostic factors in breast cancer and patient survival rates. RESULTS: HDAC1 expression was significantly reduced in proportion to higher histologic grade, higher nuclear pleomorphism score, and higher mitotic counts, and with lower estrogen receptor expression. Furthermore, it was significantly associated with the survival rate. CONCLUSIONS: HDAC1 expression is a good prognostic indicator in IDC.