Abstract: Objective To examine the expressions of JMJD3, matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) in invasive ductal breast carcinoma, their association with the clinicopathological features of the patients and the effect of JMJD3 overexpression on proliferation and MMP-2 and VEGF expressions in breast cancer cells. Methods The protein and mRNA expressions of JMJD3, MMP-2, and VEGF in invasive ductal breast carcinoma and paired adjacent tissues were detected by immunohistochemistry and RT-PCR, respectively, and their correlation with the clinicopathological characteristics of the patients was analyzed. Kaplan-Meier survival analysis was used to evaluate the correlation of JMJD3, MMP-2 and VEGF expression levels with the survival of the patients. In breast cancer MDA-MB-231 cells transfected with a JMJD3-expression plasmid, the expression of Ki67 was examined immunohistochemically, the cell proliferation was assessed with CCK8 assay, and the mRNA expressions of MMP-2 and VEGF were detected with RT-PCR. Results Breast cancer tissues had significantly lower JMJD3 expression and higher MMP-2 and VEGF expressions at both the mRNA and protein levels than the adjacent tissue (P<0.05). The positivity rates of JMJD3, MMP-2 and VEGF in breast cancer tissues were significantly correlated with tumor diameter, differentiation, TNM stage, lymph node metastasis, and molecular subtypes (P<0.05). KaplanMeier analysis showed that JMJD3 expression level was positively while MMP-2 and VEGF were inversely correlated with the disease-free survival time of the patients (P<0.05). Cox regression analysis identified JMJD3, MMP-2, VEGF and tumor differentiation as independent prognostic factors of breast cancer. Spearman correlation analysis suggested a negative correlation of JMJD3 with MMP2 (r=-0.569, P<0.05) and VEGF (r=-0.533, P<0.05) and a positive correlation between MMP2 and VEGF (r=0.923, P<0.05). In MDA-MB-231 cells, overexpression of JMJD3 inhibited the proliferation of MDA-MB-231 cells and
the expression of MMP-2 and VEGF. Conclusion The expressions of JMJD3, MMP-2 and VEGF in invasive ductal breast carcinoma are closely correlated to tumor proliferation, invasion, metastasis and prognosis and can be used for prognostic evaluation of breast cancer.

Key words: invasive ductal carcinoma of breast, JMJD3, matrix metalloproteinase-2, vascular endothelial growth factor, clinicopathological features