OBJECTIVETo investigate the expression of EZH2 in breast cancer and its clinicopathological significance.

METHODSEighty cases of invasive breast cancer with complete clinlcpathological data and follow-up information were enrolled in the study. The expressions of ER, PR, HER-2, CK5/6, CK14, EGFR and EZH2 proteins were detected by immunohistochemistry (IHC). The relationship of EZH2 expression with molecular subtypes and prognosis of breast cancer was analyzed.

RESULTSIn 80 cases of breast cancer, there were 49 cases of Luminal subtype, 8 cases of HER-2(+) subtype, 20 cases of Basal-like subtype and 3 cases of Normal breast-like subtype. The molecular subtypes of breast cancer were associated with menopausal status of patients. Luminal subtype had the highest overall survival rate, while the Basal-like carcinomas were associated with the lowest survival (P< 0.05). The overall EZH2-positive expression rate was 45.00% and the expression was correlated with axillary lymph node metastasis, histological grading and clinical staging of breast cancer (P < 0.05). The EZH2-positive expression rates in Luminal subtype, HER-2(+) subtype and Basal-like subtype of breast cancers were 34.6%,50.0% and 70.0%, respectively (P <0.05).

CONCLUSIONPositive expression of EZH2 may indicate a poor prognosis of breast cancer patients and it might be used as a novel therapeutic target for breast cancer of Basal-like subtype.