转移性乳腺癌循环肿瘤细胞的上皮间质转化水平对化疗疗效的预测意义

摘要

目的 检测转移性乳腺癌患者外周血循环肿瘤细胞(CTCs)不同亚型相关基因的表达,探讨其对化疗疗效的预测意义.方法 应用免疫磁性分选(MACS)技术联合逆转录-聚合酶链反应(RT-PCR)法检测58例转移性乳腺癌患者和10例健康人外周血中CTCs上皮型标志物上皮角蛋白(CK18、CK19)和间质型标志物(波形蛋白、纤连蛋白)mRNA的表达.分析上皮型标志物及间质型标志物表达与不同亚型乳腺癌之间的关系,并分别评估具有不同表型CTCs患者之间疗效的差异.结果 在10例健康志愿者的血液样本中,未检测出CK18、CK19、波形蛋白和纤连蛋白mRNA的表达.在58例转移性乳腺癌患者的血液样本中,检测出36例(62.1％)上皮角蛋白表达,19例(32.8％)间质型标志物表达.Luminal A组和HER-2阳性组的上皮型标志物阳性表达率高于三阴性乳腺癌组(P=0.008),而间质型标志物阳性表达率则低于三阴性乳腺癌组(P＜0.001).根据不同标志物的表达情况,将患者分为CKs +/EMT-组、CKs-/EMT-组、CKs +/EMT+组和CKs-/EMT+组,4组有效率依次为76.7％、55.6％、33.3％和15.4％,差异有统计学意义(P =0.002).间质型标志物阴性者的化疗有效率高于间质型标志物阳性者(71.8％vs.15.8％,P=0.000).结论 转移性乳腺癌患者中部分CTCs将发生上皮间质转化而丢失上皮型细胞的表型,获得间质型细胞表型.间质型CTCs因具有更强的抵抗化疗药物的能力而存活,这可能是三阴性乳腺癌疗效不佳的原因之一.%Objective To detect the levels of different phenotypic circulating tumor cells(CTCs) in patients with metastatic breast cancer( MBC) and discuss the predictive significance of CTCs on curative effect. Methods We detected the expression of epithelial (CK18, CK19) and mesenchymal ( vimentin, fibronectin) markers in CTCs from 58 MBC patients and 10 healthy people by magnetic activated cell sorting(MACS) technology combined with RT-PCR. Curative effect of chemotherapy in MBC patients with different CTCs subgroups was evaluated using RECIST criteria. Results There was no positive expression of CK18 , CK19, vimentin and fibronectin mRNA in blood samples from 10 healthy volunteers. Among 58 MBC samples, 62. 1% (36/58) was found to express the CKs epithelial markers and 32. 8% ( 19/58) were found to express the mesenchymal markers. In three different breast cancer subgroups , the positive rate of epithelial markers in luminal A and HER-2 positive subgroups higher than that in the triple negative subgroups ( P = 0. 008 ) . However, the expression of the mesenchymal markers was observed to be reversed ( P < 0. 001) . Based on the expression of epithelial( CKs) and mesenchymal( EMT) markers in CTCs, the patients could be divided into CKs + /EMT — group, CKs —/EMT - group, CKs +/EMT + group and CKs -/EMT + group. The response rates of 4 group were 76. 7% , 55. 6% , 33. 3% and 15.4% , respectively. There was significant difference (P < 0. 05). After two cycles of chemotherapy, the overall response rate(ORR) of EMT + patients was lower than that of EMT - patients( 15. 8% vs. 71. 8% , P =0. 000). Conclusion Some CTCs undergo EMT and subsequently lose their epithelial markers, such as cytokeratins, and gain the mesenchymal markers, such as vimentin and fibronectin. The presence of mesenchymal CTCs predicted resistance to chemotherapy and they maybe one of the reasons of invalid therapy of triple negative breast cancer.