摘要
肿瘤抑制基因p16定位于 9号染色体短臂 2区 1带 ,编码细胞周期调节蛋白p16 ,p16基因失活将导致细胞增殖失控。研究证实肿瘤抑制基因启动子区域 5′CpG岛甲基化是导致转录水平上基因失活的重要机制。为了研究p16基因甲基化状态及其表达异常与子宫内膜癌发生的关系 ,采用甲基化特异性PCR(MSP)、免疫组化及PCR方法检测 6 2例子宫内膜癌及相应癌旁组织、10例相应年龄正常子宫内膜中p16基因 5′CpG岛甲基化状态、p16蛋白表达及p16基因外显子E1和E2 表达缺失情况。结果表明癌旁及正常子宫内膜p16基因无甲基化 ,且无p16蛋白、外显子 1和 2的表达异常。 6 2例子宫内膜癌中 ,15例甲基化 ,占 2 4 2 %;33例p16蛋白表达下降或无表达 ,占5 4 8%;p16基因外显子 1缺失率 16 1%(10 /6 2 ) ,外显子 2缺失率为 30 6 %(19/6 2 ) ,两者均缺失 9 6 8%(6 /6 2 ) ,至少其中 1种缺失 4 6 6 %(2 9/6 2 )。提示p16基因失活在子宫内膜癌中多见且与病理分级、临床分期密切相关。p16基因甲基化在子宫内膜癌的发生中起着重要作用。MSP法测定基因甲基化状态准确且简便可行。
The tumor suppressor gene p16,located on chromosome 9p21,encodes the cell cycle regulatory protein,p16.Inactivation of the p16 gene could lead to uncontrolled cell growth.It was examined that methylation of the p16 gene 5′CpG island of the tumor suppressor gene may be an important mechanism for transcriptional inactivation.In order to determine the role of methylation status of the 5′CpG island and abnormal expression of incarcinogenesis of endometrial carcinoma(EC),Methylation-Specific PCR (MSP) was used to determine the methylation status of p16 gene 5′CpG islands of 62 cases of EC.Loss or decrease of p16 expression was analyzed by immunohistochemistry(IHC) and homozygous deletion of exon1(E_1) and exon2 (E_2) was determined by complex PCR.Ten specimens of normal tissues and adjacent tissues of tumor displayed no methylation and showed normal expression of p16.In E_1 and E_2 of the 62 EC,we found that 24.2%(15/62) were methylated,54.8%(33/62) lost or reduced p16 expression,16.1%(10/62) and 30.6%(19/62) had deletions of E_1 and E_2 respectively.There were 9.68%(6/62) and 46.6%(29/62) deletions of both or either of E_1 and E_2 respectively.Inactivation of p16 gene is a frequent event and positively correlated with pathological grades and clinical stages in EC.p16 gene methylation was an important event in the development of EC.MSP is an accurate and relatively simple method for evaluating the methylation status of a related gene.
基金
黑龙江省自然科学基金资助 (编号 :D0 1 41)~~