Objective: To analyze the expression pattern, mechanism and clinical significance of melanoma-associated antigen-C2 (MAGE-C2) in tumor-free breast specimens, breast benign disease specimens and breast cancer specimens. Methods: Reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry were used to investigate the expressions of MAGE-C2 in 60 tumor-free breast specimens, 60 breast benign disease specimens and 60 breast cancer specimens. The correlation of MAGE-C2 expression with clinicopathological parameters and prognosis of breast cancer patients were analyzed. The expression of MAGE-C2 was also detected by RT-PCR in breast cancer cell MCF-7 and MDA-MB-231 treated with DNA methylase inhibitor 5-aza-2'-deoxycytidine (5-aza-CdR) and histone deacetylase inhibitor trichostatin A (TSA). Results: The positive expression rates of MAGE-C2 mRNA and protein were 61.7% (37/60) and 58.3% (35/60) in breast cancer specimens, respectively, while negative expressed in breast and begin disease specimens. MAGE-C2 protein expression was associated with tumor grade, histological type and blood vessel invasion of breast cancer patients (P<0.05). The incidence of recurrence-free survival of patients with positive MAGE-C2 expression were lower than that of patients with negative MAGE-C2 expression (P<0.05). Multivariate Cox regression analysis showed that the clinical stage (P<0.01), lymph node metastasis (P<0.05) and MAGE-C2 expression (P<0.05) were the independent prognostic factors of breast cancer patients. The MAGE-C2 mRNA was not observed in the control and TSA treated breast cancer cells while upregulated in the 5-aza-CdR treated cells. Besides, 5-aza-CdR combined with TSA further enhanced MAGE-C2 mRNA level in breast cancer cells (P<0.05). Conclusions: MAGE-C2 is one of the tumor-specific antigen and its expression is related with the poor prognosis of breast cancer patients. DNA methylation and histone acetylation may be an important regulation mechanism of MAGE-C2 gene expression.
目的： 探讨黑色素瘤相关抗原C2(MAGE-C2)在乳腺正常组织、良性病变组织和癌组织中的表达、表达机制及临床意义。 方法： 分别采用逆转录聚合酶链反应(RT-PCR)和免疫组化法检测60例乳腺正常组织、60例乳腺良性病变组织和60例乳腺癌组织中MAGE-C2 mRNA和蛋白的表达，分析其与乳腺癌患者临床病理特征及预后的关系。以DNA甲基化酶抑制剂5-氮杂-2′-脱氧胞苷(5-aza-CdR)和组蛋白去乙酰化酶抑制剂曲古抑菌素A(TSA)干预人乳腺癌细胞MCF-7和MDA-MB-231后，采用RT-PCR法检测MAGE-C2 mRNA表达的变化。 结果： 乳腺癌组织中MAGE-C2 mRNA阳性表达率为61.7%(37/60)，MAGE-C2蛋白阳性表达率为58.3%(35/60)，乳腺正常组织和良性病变组织中未见MAGE-C2 mRNA及蛋白的表达。MAGE-C2蛋白表达与乳腺癌的病理类型、组织学分级、脉管瘤栓有关(均P<0.05)。MAGE-C2蛋白表达阳性乳腺癌患者的无复发生存率低于MAGE-C2蛋白表达阴性的患者(χ(2)＝4.467，P＝0.035)。多因素Cox回归分析显示，临床分期(HR＝4.715，P＝0.004)、淋巴结转移(HR＝3.827，P＝0.023)和MAGE-C2蛋白表达(HR＝4.229，P＝0.026)是乳腺癌患者无复发生存的独立影响因素。对照组和TSA组乳腺癌细胞中未见MAGE-C2 mRNA表达，5-aza-CdR组乳腺癌细胞中可见MAGE-C2 mRNA表达(MCF-7细胞为0.2914±0.0274，MDA-MB-231细胞为0.4808±0.0288)，联合应用5-aza-CdR和TSA可使乳腺癌细胞中MAGE-C2 mRNA表达进一步增加(MCF-7细胞为1.0357±0.0644，MDA-MB-231细胞为1.6013±0.0675)。 结论： MAGE-C2是肿瘤特异性抗原，其表达与乳腺癌患者的不良预后有关，DNA甲基化和组蛋白乙酰化可能是调控MAGE-C2基因表达的重要机制。.
Keywords: 5-aza-2′-deoxycytidine; Breast neoplasms; Melanoma-associated antigen-C2; Trichostatin A.