Ding Yi, Le Xiao-Ping, Zhang Qin-Xian, Du Peng
Molecular Cell Biology Research Center, Medical College of Zhengzhou University; 40 Daxue Road, Zhengzhou 450052, Henan Province, China.
World J Gastroenterol. 2003 Mar;9(3):423-6. doi: 10.3748/wjg.v9.i3.423.
To study methylation, frequencies of homozygous deletion and mutation of p16 gene in gastric carcinoma.
The methylation pattern in exon 1 and exon 2 of p16 gene was studied with polymerase chain reaction (PCR), using methylation sensitive restriction endonuclease HpaII and methylation insensitive restriction endonuclease MspI. PCR technique was used to detect homozygous deletions of exon 1 and exon 2 of p16 gene and single strand conformation polymorphism (SSCP) technique was used to detect the mutation of the gene.
Hypermethylation changes in exon 1 and exon 2 of p16 gene were observed in 25 % and 45 % of 20 gastric cancer tissues, respectively, while no methylation abnormality was found in normal tissues. The homozygous deletion frequency of exon 1 and exon 2 of p16 gene in 20 gastric cancer tissues was 20 % and 10 %, respectively. No mutation was found in exon 1 of p16 gene, while abnormal single strands were found in 2 (10 %) cases in exon 2 as detected by SSCP.
The results suggest that hypermethylation and abnormality of p16 gene may play a key role in the progress of gastric cancer. Hypermethylation of exon 2 of p16 gene may have effects on the carcinogenesis of gastric mucosa and may be a later event.
研究胃癌中p16基因的甲基化、纯合缺失及突变频率。
采用甲基化敏感限制性内切酶HpaII和甲基化不敏感限制性内切酶MspI，通过聚合酶链反应（PCR）研究p16基因外显子1和外显子2的甲基化模式。运用PCR技术检测p16基因外显子1和外显子2的纯合缺失，采用单链构象多态性（SSCP）技术检测该基因的突变。
在20例胃癌组织中，分别有25%和45%的组织观察到p16基因外显子1和外显子2的高甲基化改变，而在正常组织中未发现甲基化异常。20例胃癌组织中p16基因外显子1和外显子2的纯合缺失频率分别为20%和10%。p16基因外显子1未发现突变，而通过SSCP检测发现外显子2中有2例（10%）出现异常单链。
结果表明，p16基因的高甲基化和异常可能在胃癌进展中起关键作用。p16基因外显子2的高甲基化可能对胃黏膜癌变有影响，且可能是一个较晚期事件。
