目的：探讨雌激素受体（estrogen receptor, ER）阳性的乳腺癌患者癌组织中Efp和Plk3的表达及其临床意义和可能的作用机制。方法：采用免疫组织化学法检测于2010年1月至6月在河北医科大学第四医院乳腺科住院的86例ER阳性患者乳腺癌组织中Efp和Plk3的蛋白表达，并分析两者表达的相关性及与临床病理指标的关系。采用qRT-PCR法检测乳腺癌细胞MCF-7和MDA-MB-231中ER、Efp mRNA的表达情况,采用RT-PCR及Western blotting法检测雌激素刺激后ER阳性乳腺癌细胞MCF-7中Efp、Plk3基因的表达变化,采用Western blotting法检测雌激素及蛋白酶抑制剂MG132处理后MCF-7细胞中Efp、Plk3的表达变化。结果： 86例ER阳性的乳腺癌组织中，55例Efp表达阳性（64.0%）,28例Plk3表达阳性（326%）。Efp表达阳性组织中Plk3表达阳性为23.6%， Efp表达阴性组织中Plk3表达阳性为48.4%， Efp和Plk3蛋白表达存在明显的负相关（P<0.05），Efp蛋白表达与乳腺患者的淋巴结转移状况呈明显正相关（P<0.05），Plk3蛋白表达与乳腺癌患者的淋巴结转移状况呈明显负相关（P<0.05）。MCF-7细胞ER mRNA高表达，而MDA-MB-231细胞的ER mRNA低表达。MDA-MB-231细胞经雌激素刺激后， Efp mRNA的表达未见明显改变。 MCF-7经雌激素刺激后Efp mRNA及蛋白的表达显著增加（P<0.05），而Plk3 mRNA的表达未见明显改变，未检测到Plk3蛋白的表达。MG132处理后MCF-7细胞中Plk3的蛋白表达明显上调，MCF-7经雌激素刺激后，再用MG132处理，Efp的蛋白表达显著增加（P<0.05），而Plk3蛋白表达明显下降（P<005）。结论： ER阳性乳腺癌中Efp和Plk3蛋白表达存在明显的负相关，Efp可促进Plk3的蛋白降解，并可能参与了ER阳性乳腺癌患者内分泌治疗的耐药过程。

Objective:To explore the expressions of Efp and PlK3 in patients with estroen receptor (ER) positive breast cancer and to analyze their clinical significance and possible mechanisms of the actions. Methods: Immuno histochemistry was used to detect expressions of Efp and PlK3 proteins in ER positive breast cancer tissues of 86 cases who were hospitalized in Department of Breast Surgery, the 4th Hospital of Hebei Medical University during January to June, 2010. Correlation between expressions of the both protein and their relationship with clinical pathological features were analyzed. Expressions of ER and Efp mRNAs in breast cancer MCF-7 and MDA-MB-231 line cells were detected by qRT-PCR assay. RT-PCR and Western blotting assays were used to check expression changes of Efp and Plk3 genes in ER positive breast cancer MCF-7 line cell after stimulation of estrogen. Expression changes of Efp and Plk3 proteins in the MCF-7 cell after treatments with estrogen and protease inhibitor MG132 were detected by Western blotting assay. Results:In ER positive breast cancer tissues of the 86 cases, Efp expression of 55 cases was positive (64.0%) and PIk3 expression of 28 cases was positive (32.6%). Positive expression of PIk3 was 23.6% in the tissues of Efp positive expression and that was 48.4% in the tissues of Efp negative expression. There was a significant negative correlation between expressions of Efp protein and Plk3 protein (P<0.05). Expression of Efp protein and lymph node metastasis of the patients with breast cancer were obviously positive correlation (P<0.05), and expression of Plk3 protein and lymph node metastasis of the patients with breast cancer were obviously negative correlation （P<0.05). Expression of ER mRNA in the MCF-7 cell was high, but expression of ER mRNA in the MDA-MB-231 cell was low. After stimulated by estrogen, Efp mRNA expression of the MDA-MB-231 cell did not obviously changed. After stimulated by estrogen, mRNA and protein expressions of Efp gene of the MCF-7 cell significantly increased (P<0.05), however expressions of Plk3 mRNA and its protein did not markedly changed, expression of Plk3 protein was not detected also. After treated by MG132, expression of Plk3 protein in the MCF-7 cell evidently increased. After stimulated by estrogen, treatment of MG132 significantly increased expression of Efp protein and decreased expression of Plk3 protein in the MCF-7 cell (all P<0.05). Conclusion: There was obvious negative correlation between expressions of Efp and Plk3 proteins in the ER positive breast cancer. Efp protein could improve degradation of Plk3 protein, and could involve in drug resistance process of endocrine therapy for patients with ER positive breast cancer.

国家自然科学基金资助项目(No.81001178)；河北省科技研发计划自筹项目资助（No.152777184）