p16INK4A表达水平差异与子宫内膜病变发生及发展的关系

Disfigurement of p16INK4A gene expression in the development of endometrial diseases

目的研究抑癌基因p16INK4A在不同程度子宫内膜病变中的表达水平变化,分析这种差异表达与甲基化及病变程度的关系。方法逆转录-聚合酶链法(RT-PCR)检测正常子宫内膜组织、子宫内膜复杂性增生、子宫内膜不典型增生、子宫内膜癌中p16INK4A基因的表达水平,每组均检测30例标本。蛋白免疫印迹法分析各组p16INK4A蛋白水平的表达。甲基化特异性的PCR技术(MSP)对p16INK4ADNA进行甲基化分析。结果随着子宫内膜病变程度的加重,p16INK4A的表达量逐渐降低,子宫内膜癌与其他病变比较,差异有统计学意义(P<0.05);不典型增生与其他病变比较差异均有统计学意义(P<0.05);子宫内膜复杂性增生与正常子宫内膜比较差异无统计学意义(P>0.05)。蛋白的表达检测也得到相同的结果。MSP进一步分析各组织中p16INK4A的甲基化状态,发现在子宫内膜癌组织中有19例存在不同程度的p16INK4A的甲基化,子宫内膜不典型增生组织中有11例甲基化,子宫内膜复杂性增生组织中有1例甲基化,这些甲基化的组织同时伴有p16INK4A蛋白的表达异常。甲基化与子宫内膜癌手术-病理分期有关(P<0.05)。正常子宫内膜组织中未发现p16INK4A甲基化。结论 p16INK4A作为一种抑癌基因,它的表达缺失或下降在子宫内膜病变的发生及发展过程中起重要作用,表达越低,内膜的病变程度越重,基因甲基化可能是导致这种异常表达的主要原因。

Objective To evaluate the different expression of p16INK4A gene in endometrial diseases and analyze the relation between this alteration and the promoter methylation of p16INK4A DNA.Methods Choose the tissues including normal endometrium,complex hyperplasis,atypical hyperplasia,endometrial carcinoma,every group including 30 specimens.The level of p16INK4A mRNA was detected with reverse transcription polymerase chain reaction（RT-PCR）.Protein was tested by Western Blot.Methylation specific PCR（MSP） was used to check whether it was methylated in the promoter of p16INK4A exon.Results The expression of p16INK4A mRNA decreased step by step accompanied with the diseases development.In endometrial carcinoma,the expression of p16INK4A mRNA decreased significantly or absolutely defaulted when compared with the other tissues（P＆lt;0.05）.Atypical hyperplasia tissues also significant when compared with the other two groups（P＆lt;0.05）.19 endometrial carcinoma specimens were found methylated in their first exon and the rate was 63.33%,What′s more,methylation was related with the surgical-pathological stage of the patients.Conclusion That disfigurement of p16INK4A gene expression plays an important role in the development of endometrial caicinoma,and this alteration is partially caused by methylation of p16INK4A first exon.