Ras及erbB2基因在胃粘膜良恶性病变中的表达

EXPRESSION OF RAS AND ERBB2 IN BENIGN AND MALIGNANT LESIONS OF THE STOMACH

作者用免疫组化技术研究了Ｐ２１￣（ｒａｓ）和Ｐ１８５￣（ｅｒｂＢ２）在正常胃粘膜、肠化生、异型增生、肠型及弥漫型胃癌中的表达。结果表明，肠型胃癌Ｐ２１和Ｐ１８５阳性表达率均显著高于弥漫型胃癌，即两型胃癌的分子生物学改变有所不同，提示它们的发病机理亦有所不同。Ｐ２１并非只在癌细胞中呈特异的阳性表达，因此不宜做为胃粘膜恶性变的标记物。而Ｐ１８５仅在肠型胃癌的细胞膜中呈阳性表达，其它各组病变均无胞膜着染现象，因此Ｐ１８５细胞膜阳性表达，有可能做为胃粘膜上皮细胞恶性变的标记。此研究还用原位杂交方法检测了３例胃癌组织及胃癌细胞系ＭＧＣ８０３和人胚胃转化细胞ＧＥＳ１中ｅｒｂＢ２基因的表达，从而在ｍＲＮＡ和蛋白两个水平上证实了胃癌中存在ｅｒｂＢ２基因的过表达。

AbstractThe expression of P185￣(erbB2)and P21￣(ras)was examined immunohistochemically in normal mu-cosa,intestinal metaplasia,dysplasia,intestinal type and diffuse type carcinoma of the stomach.The positive rates of P185 and P21 in the intestinal type carcinoma were significantly higher thanthose of the diffuse type.The results suggest that the two types of gastric carcinoma differ notonly in histo-morphology but also in molecular mechanism.P21 immunopositivity is unlikely aspecific marker of malignancy in gastric mucosa because of no significant difference of immunore-activity among intestinal metaplasia,dysplasia,and carcinoma of the stomach.The positivestaining of cell membrane for P185 was observed specifically in intestinal type carcinoma,but wasabsent in all other lesions.So it appears to be a useful marker of malignant change in the gastricmucosa.Overexpression of erbB2 gene in gastric carcinoma was demonstrated both at the mRNAlevel by in situ hybridization and at the protein level by immunohistochemical staining.