Muta H, Noguchi M, Kanai Y, Ochiai A, Nawata H, Hirohashi S
Pathology Division, National Cancer Center Research Institute, Tokyo.
Jpn J Cancer Res. 1996 Aug;87(8):843-8. doi: 10.1111/j.1349-7006.1996.tb02109.x.
To clarify the significance of E-cadherin gene alterations in the development of diffuse-type adenocarcinoma of the stomach, we analyzed mutations of the E-cadherin gene using the polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) method followed by direct sequencing. Twenty-two signet ring cell carcinomas of the stomach (10 intramucosal and 12 advanced cancers) were examined. Genomic DNA was extracted separately from cancerous and non-cancerous tissues and PCR-SSCP analysis was performed on exons 5 to 9 and the adjacent 30- to 40-base-pair intron sequences of the E-cadherin gene. Mobility shifts were found in 2 of the 10 intramucosal cancers. In 2 of the 12 advanced cancers, abnormalities of the E-cadherin gene were observed in intramucosal lesions as well as in deeply invaded areas. These results indicated that E-cadherin gene mutations are an early event in the development of signet ring cell carcinoma of the stomach. Direct sequencing revealed that the locations of mutations of the E-cadherin gene included the branch point sequence in the intron which is responsible for RNA splicing. Reverse transcriptase-PCR demonstrated aberrant RNA splicing in a case with a branch point mutation, suggesting that branch point mutations play an important role in functional modifications of E-cadherin in signet ring cell carcinoma of the stomach.
为阐明E-钙黏蛋白基因改变在胃弥漫型腺癌发生发展中的意义，我们采用聚合酶链反应单链构象多态性（PCR-SSCP）方法并结合直接测序分析了E-钙黏蛋白基因的突变情况。对22例胃印戒细胞癌（10例黏膜内癌和12例进展期癌）进行了检测。分别从癌组织和非癌组织中提取基因组DNA，对E-钙黏蛋白基因的第5至9外显子及其相邻的30至40个碱基对的内含子序列进行PCR-SSCP分析。在10例黏膜内癌中有2例出现迁移率改变。在12例进展期癌中有2例，在黏膜内病变以及深部浸润区域均观察到E-钙黏蛋白基因异常。这些结果表明，E-钙黏蛋白基因突变是胃印戒细胞癌发生发展过程中的早期事件。直接测序显示，E-钙黏蛋白基因的突变位置包括负责RNA剪接的内含子分支点序列。逆转录聚合酶链反应（RT-PCR）在1例存在分支点突变的病例中证实了异常的RNA剪接，提示分支点突变在胃印戒细胞癌中E-钙黏蛋白的功能修饰中起重要作用。
