人卵巢浆液性囊腺癌中p16^(INK4a)基因失活机制探讨  

Studies on the mechanisms of p16^(INK4a) gene inactivation in human serous ovarian carcinoma.

作　　者：王刚[1] 王世阆[2] 王靖华[3] 张崇淑[2] 

机构地区：[1]广东省佛山市第一人民医院妇产科,佛山528000 [2]华西医科大学附属第二医院妇产科 [3]华西医科大学附属第一医院病理科

出　　处：《现代妇产科进展》2001年第5期349-352,共4页Progress in Obstetrics and Gynecology

基　　金：全国高等院校博士点专项基金资助课题

摘　　要：目的 :探讨人卵巢浆液性囊腺癌中p16INK4a基因表缺失的机制 ,为p16INK4a相关性基因治疗提供理论依据。方法 :采用PCR、PCR SSCP、甲基化特异性PCR和DNA测序等方法重点检测p16INK4a蛋白表达缺失的卵巢浆液性肿瘤组织中p16INK4a基因缺失、突变和5’ CpG岛甲基化 ,分析它们与肿瘤预后的关系。结果 :4 3份p16INK4a蛋白表达阴性标本中检测到p16INK4a基因纯合缺失 4例 ,第 1、2外显子各 2例 ;第 2外显子点突变 2例 ,经DNA测序确定 1例为第 2外显子 4 94位G→T变异 ,位于非编码区 ;1例为第 2外显子 34 3位G→T变异 ,相应的氨基酸变异为第 115位缬氨酸 (GTG)→亮氨酸 (TTG) ;应用MSP法检测出 14例 (32 .6% ) 5’ CpG岛甲基化并经DNA测序证实。p16INK4a蛋白表达阳性的 14份标本中仅检测到 1例 (7.14% ) 5’ CpG岛甲基化 ,而未发现基因缺失和点突变证据。 34例卵巢浆液性囊腺癌患者中p16INK4a基因异常 16例 ,较无异常 18例预后更差 (P =0 .0 0 0 8)。结论 :5’ CpG岛甲基化可能是卵巢浆液性囊腺癌中p16INK4a基因表达缺失的主要原因 。Objective:To explore the mechanisms of p16 INK4a gene inactivation in human serous ovarian tumor.Methods:Polymerase chain reaction(PCR),PCR-single-strand conformational polymorphism(PCR-SSCP) and methylation-specific PCR(MSP) assay were carried out to detect homozygous deletion,point mutation and methylation of p16 INK4a gene respectively.DNA sequencing was performed to confirm the suspected p16 INK4a gene alterations.Results:DNA obtained from 57 samples were available for further analysis,including 43 with negative immunostaining for p16-protein and 14 with positive immunostaining.In the former group,4 homozygous deletions of p16 INK4a gene were detected by PCR,and methylations of 5'-CpG island were detected in 14 cases by MSP and confirmed by DNA sequencing,and PCR-SSCP showed 2 cases of point mutations in exon-2 of p16 INK4a ,which were confirmed by DNA sequencing as G→T at nucleotide 494 and G→T at nucleotide 343.No mutation or deletion were found in 14 cases with positive p16 expression except 1 methylation.Those patients with abnormal p16 INK4a gene had poorer prognoses than those without p16 INK4a alteration(P<0.05).Conclusion:p16 INK4a gene may be involved in the tumorigensis and progression of human ovarian carcinoma as tumor suppressors.Methylation of 5'-CpG island may be the main mechanism of p16 INK4a gene inactivation in serous ovarian carcinomas,although some loss of p16 expression may be induced by homozygous deletion or mutation of the gene.

关 键 词：P16^INK4A 卵巢肿瘤 基因变异 聚合酶链反应 癌 

分 类 号：R737.31[医药卫生—肿瘤]