Objective: To investigate the expressions of enhancer of zeste homolog 2 (EZH2) and chromobox homolog 7 (CBX7) in breast cancer tissue and their clinical significance. Methods: The gene and protein expressions of EZH2 and CBX7 in normal mammary tissues, benign breast tumor tissues and breast cancer tissues were determined by RT-PCR and immunohistochemical staining, respectively. The relationship between EZH2 and CBX7 expressions in breast cancer tissue, and the relations of their expressions with clinicopathologic factors of breast cancer were analyzed. Results: In normal mammary tissue, benign breast tumor tissue and breast cancer tissue, both EZH2 mRNA expression level and protein expression rate were increased significantly in an increasing order, whereas those of CBX7 showed exactly opposite patterns, and all the differences reached statistical significance (all P<0.05). Both the mRNA and protein expression between EZH2 and CBX7 in breast cancer tissue exhibited a significant negative correlation (r=–0.414, P=0.008; r=–1.000, P=0.015). Both mRNA and protein expression of EZH2 and CBX7 were significantly related to lymph node metastasis and clinical stage (all P<0.05), but not associated with the age, menstrual status, tumor size or histologic classification of the patient (all P>0.05). Conclusion: EZH2 expression is increased and CBX7 expression is decreased in breast cancer tissue, and the reciprocity between them may participate in the processes of the malignant transformation of breast tissue as well as invasion and metastasis of breast cancer.