Objective To investigate the expressions of extracellular matrix metalloproteinase inducer(EMMPRIN),matrix metalloproteinase-9(MMP-9),lysine demethylase 6B(KDM6B)proteins and their correlation with clinicopathologic features in invasive breast cancer,and analyze the correlation among the three proteins and their value in pathological diagnosis of invasive breast cancer.Methods The surgical biopsy specimens of 124 patients with invasive breast cancer who were admitted to the Department of Pathology,the Fifth Clinical Medical College of Henan University of Chinese Medicine/People's Hospital of Zhengzhou from January 2014 to December 2017 were selected as research subjects,and 20 low-grade intraductal carcinoma tissue specimens,27 high-grade intraductal carcinoma tissue specimens,and 22 adjacent tissue specimens＞1 cm away from the invasive breast cancer were selected as controls.The expressions of EMMPRIN,MMP-9 and KDM6B proteins in cancer-adjacent tissues,low-grade intraductal carcinoma tissues,high-grade intraductal carcinoma tissues and invasive breast cancer tissues were detected by immunohistochemistry.The relationship between the relative expressions of EMMPRIN,MMP-9 and KDM6B proteins and clinicopathologic features of invasive breast cancer was analyzed,Spearman correlation analysis was used to evaluate the correlation of EMMPRIN,MMP-9 and KDM6B proteins in breast cancer tissues,and receiver operating characteristic(ROC)curve was adopted to evaluate the diagnostic value of EMMPRIN,MMP-9 and KDM6B for invasive breast cancer.Results The relative expressions of EMMPRIN and MMP-9 proteins in high-grade intraductal carcinoma and invasive breast cancer tissues were significantly higher those in cancer-adjacent tissues and low-grade intraductal carcinoma tissues,and the relative expression of KDM6B protein was significantly lower than those in cancer-adjacent tissues and low-grade intraductal carcinoma tissues(P＜0.05);the relative expressions of EMMPRIN and MMP-9 proteins in invasive breast cancer tissues were significantly higher those in high-grade intraductal carcinoma tissues,and the relative expression of KDM6B protein was significantly lower than that in high-grade intraductal carcinoma tissues(P＜0.05);there was no statistically significant difference in the relative expressions of EMMPRIN,MMP-9 and KDM6B proteins between cancer-adjacent tissues and low-grade intraductal carcinoma tissues(P＞0.05).The relative expressions of EMMPRIN and KDM6B proteins were not related to the age,tumor location and tumor diameter of patients with invasive breast cancer(P＞0.05),and the relative expression of MMP-9 protein was not related to the age and tumor location of patients with invasive breast cancer(P＞0.05).Relative expressions of EMMPRIN,MMP-9 and KDM6B proteins were correlated with WHO grading,lymph node metastasis,and tumor,node and metastasis(TNM)staging of invasive breast cancer(P＜0.05),and the relative expression of MMP-9 protein was correlated with the tumor diameter(P＜0.05).In the WHO grades Ⅰ,Ⅱ,and Ⅲ of invasive breast cancer,the relative expressions of EMMPRIN and MMP-9 proteins increased sequentially,while the relative expression of KDM6B protein decreased sequentially(P＜0.05);the relative expressions of EMMPRIN and MMP-9 proteins in the lymph node metastasis group were significantly higher than those in the non-lymph node metastasis group,and the relative expression of KDM6B protein was significantly lower than that in the non-lymph node metastasis group(P＜0.05);the relative expressions of EMMPRIN and MMP-9 proteins in TNM stages Ⅲ-Ⅳ were significantly higher than those in stages Ⅰ-Ⅱ(P＜0.05),while the relative expression of KDM6B protein was significantly lower than that in stages Ⅰ-Ⅱ(P＜0.05).In the group of invasive breast cancer with diameter≤2 cm,2 to 5 cm,and＞5 cm,the relative expression of MMP-9 protein increased sequentially(P＜0.05).Spearman correlation analysis showed that the expression of EMMPRIN was positively correlated with MMP-9 protein in invasive breast cancer tissues(r=0.990,P=0.000),the expression of EMMPRIN was negatively correlated with KDM6B protein(r=-0.606,P=0.000),and the expression of MMP-9 was negatively correlated with KDM6B protein(r=-0.612,P=0.000).ROC curve analysis showed that the area under the curve(AUC)of EMMPRIN protein for diagnosing invasive breast cancer was 0.875[95％confidence interval(CI):0.823-0.926,P＜0.05],with an optimal threshold of 10.043,sensitivity of 79.0％,and specificity of 76.8％;the AUC of MMP-9 protein in diagnosing invasive breast cancer was 0.863(95％CI:0.808-0.917,P＜0.05),with an optimal threshold of 10.070,sensitivity of 74.2％,and specificity of 76.8％;the AUC of KDM6B protein in diagnosing invasive breast cancer was 0.267(95％CI:0.196-0.338,P＜0.05),with an optimal threshold of 11.003,sensitivity of 71.0％,and specificity of 98.6％.Conclusion EMMPRIN,MMP-9 and KDM6B are related to the occurrence and development of invasive breast cancer.Detection of the expressions of EMMPRIN,MMP-9 and KDM6B is helpful to the pathological diagnosis of invasive breast cancer and clinical judgment of invasion and metastasis of breast cancer.