乳腺癌中脆性组氨酸三联体异常甲基化能下调其mRNA及蛋白的表达  

Effect of abnormal methylation of FHIT gene in down-regulating the expression of FHIT mRNA and protein in breast cancer

作　　者：赵典朋[1] 贾丽燕[1] 刘桂玲[1] 李世平[1] 申安[1] 

机构地区：[1]山东省潍坊医学院附属医院普外二科,山东潍坊261031

出　　处：《中华乳腺病杂志（电子版）》2012年第1期32-36,共5页Chinese Journal of Breast Disease(Electronic Edition)

摘　　要：目的通过检测脆性组氨酸三联体(fragile histidine triad,FHIT)基因在乳腺癌组织和正常乳腺组织中的异常甲基化及其mRNA和蛋白表达情况,探讨FHIT基因在乳腺癌发生发展中的作用,为乳腺癌生物治疗及判断预后提供实验依据。方法分别应用免疫组织化学SP法、逆转录聚合酶链式反应(reverse transcription-polymerase chain reaction,RT-PCR)和甲基化特异性PCR(methylation specific PCR,MSP)检测50例乳腺癌组织和距离肿瘤5cm以外的正常乳腺组织中FHIT蛋白及其mRNA的表达情况。对FHIT表达与乳腺癌临床病理指标的关系采用卡方检验,对FHIT甲基化与蛋白、mRNA表达的关系进行Spearman相关性分析。结果免疫组织化学染色显示:FHIT蛋白在乳腺组织细胞浆内呈棕黄色颗粒状分布。FHIT在乳腺癌和正常乳腺组织中的阳性表达率分别为32.0%(16/50)和88.0%(44/50),差异有统计学意义(χ2=32.667,P=0.000);RT-PCR结果显示:在乳腺癌和正常乳腺组织中均有FHIT mRNA的表达。乳腺癌组织中FHIT条带吸光度(optical density,OD)值与相应的β-actin条带的OD值的比值(0.1081±0.0128)明显低于正常乳腺组织(0.2088±0.0137),差异有统计学意义(P<0.05),表明乳腺癌组织中FHIT的表达量减少;MSP扩增结果显示:乳腺癌组织和正常乳腺组织的甲基化率分别为46.0%(23/50)、12.0%(6/50),差异有统计学意义(χ2=14.036,P=0.000)。FHIT基因甲基化率与蛋白表达、有无淋巴结转移有关(P<0.05),而与肿瘤大小、组织学分级及TNM分期无关(P>0.05)。结论 FHIT基因在乳腺癌中的甲基化能下调其mRNA及蛋白的表达。Objective To detect the aberrant methylation of fragile histidine triad （FHIT） gene and the expression of the corresponding mRNA and proteins in breast tumor tissue and normal breast tissue, explore the role of FHIT gene in the development of breast cancer and provide experimental evidence for biotherapy and prognosis. Methods Immunohistochemical SP method, reverse transcription polymerase chain reaction （RT-PCR） and methylation specific PCR （MSP） were used to detect the protein and mRNA expressions of FHIT in 50 cases of breast tumor tissues and adjacent normal tissues over 5 cm away from the margin of tumor. The relationship between FHIT expression and clinic-pathological parameters were analyzed by chi-square test. The correlation between FHIT methylation and the FHIT mRNA and protein expression was processed by Spearman analysis. Results Immunohistochemical staining showed that FHIT protein was mainly located in the cytoplasma of breast cells, being brown granules. The positive expression ratios of FHIT were 32. 0% in breast tumor tissue and 88.0% in normal breast issue, respectively. The difference was significant （P〈0. 05 ）. RT-PCR results showed that FHIT mRNA was expressed in both breast tumor tissue and normal tissue. The ratio of FHIT band optical density （OD） value to OD value of 13-actin was 0. 1081±0. 0128 in breast tumor tissue, which was significantly lower than 0. 2088±0. 0137 in normal tissue （P〈0. 05 ）. It indicated that the expression of FHIT was decreased in breast tumor tissue. MSP results showed that FHIT methylation rate were 46. 0% （23/50） in tumor tissue, 12. 0% （6/50） in normal tissues. The difference was statistically significant （P〈O. 05 ）. FHIT methylation rate was correlated with lymph node metastasis （P〈0. 05 ）, not related with tumor size, histological grade, TNM stage （ P 〉 0. 05 ）. Conclusions Methylation of FHIT gene in breast cancer can significantly down-regulate FHIT mRNA and protein expression.

关 键 词：乳腺肿瘤 甲基化 脆性组氨酸三联体 

分 类 号：R737.9[医药卫生—肿瘤]