Expression and significance of EZH2 and DNMT1 in triple-negative breast cancer / 解放军医学杂志

ABSTRACT

Objective To probe into the expression features of EZH2 and DNMT1 in triple-negative breast cancer (TNBC), and the relations between the expression and the main clinical pathological parameters of TNBC. Methods The clinical and pathological data of 209 cases of breast cancer (including 131 cases of TNBC and 78 cases of non-TNBC) in Guangzhou Kingmed Center for Clinical Laboratory from Jan. 2008 to May 2013 were retrospectively analyzed. Immunohistochemistry SP assay was performed to determine the expressions of EZH2 and DNMT1 in 209 paraffin-embedded specimens of breast cancer and 65 specimens of normal tissue (more than 4cm away from tumor). The differences of protein expression in the specimens were compared, and correlation analysis was performed to disclose the relationship between protein expression and clinico-pathological indices. Multivariate logistic regression analysis was applied to analyze the positive expression-related factor of EZH2 and DNMT1. Spearman rank correlation analysis was used to analyse the interrelation of EZH2 and DNMT1 in TNBC. Results The positive expression rates of EZH2 in TNBC, non-TNBC and adjacent breast tissue were 86.3%, 89.7% and 40.0%, respectively, while the positive expression rates of DNMT1 were 63.4%, 66.6% and 44.6%, respectively. The positive expression rates of EZH2 and DNMT1 were higher in both TNBC and non-TNBC tissues than in adjacent breast tissue (P0.05), but the positive expression of EZH2 in TNBC was related to the pathological grade, tumor size and lymph node metastasis (P<0.05), and the positive expression of DNMT1 was related to the pathological grade and lymph node metastasis (P<0.05). Multivariate logistic regression analysis demonstrated that the pathological grade of tumor was the main factor affecting the expressions of EZH2 and DNMT1, and the expressions of EZH2 and DNMT1 in TNBC were positively correlated (r=0.34, P<0.01). Conclusion The high expressions of EZH2 and DNMT1 are correlated with the differentiation, growth and metastasis of TNBC. Combined detection of the expressions of EZH2 and DNMT1 may be more valuable in determination of prognosis of patients with TNBC.