摘要目的 通过人雄激素受体基因位点克隆性分析技术对胃癌及其癌前病变进行克隆性分析,探讨胃癌发生发展过程中单克隆发生率的变化趋势及与Ki-67表达之间的关系及其意义.方法 肠型胃癌根治标本24例,胃镜活检标本150例.采用激光显微切割技术准确获取病变腺上皮细胞,基因组DNA经甲基化敏感的Hpa Ⅱ限制性内切酶消化后,PCR扩增人雄激素受体基因,采用基因扫描技术对PCR产物进行分析.应用免疫组织化学EnVision二步法检测Ki-67在以上病变组织中的表达,并探讨其与克隆性分析结果的相关性.结果 单克隆发生率在胃黏膜肠上皮化生(15.63%,5/32)、低级别上皮内瘤变(22.22%,10/45)、高级别上皮内瘤变(69.44%,25/36)及肠型胃癌(100.0%,20/20)中逐渐增加,除胃黏膜肠上皮化生和低级别上皮内瘤变之间的差异没有统计学意义(P=0.47),其他各组之间差异均有统计学意义(P<0.01).Ki-67的阳性表达率随着病变的发展而不断升高.低级别上皮内瘤变组织中单克隆病例的Ki-67的阳性表达率显著高于多克隆病例(P<0.01),且克隆性与Ki-67的阳性表达率之间存在显著相关性(P<0.01).结论 单克隆的发生率及Ki-67的阳性表达率在胃癌发生发展过程中逐渐增加.且单克隆病变的发生与Ki-67的表达存在一定的相关性,两者的联合可用于胃癌的早期诊断及易感性的预测.

abstractsObjective To study the clonality of gastric carcinoma and precancerous lesions and its relationship with Ki-67 protein expression. Methods Formalin-fixed paraffin embedded tissues were collected from 174 cases of gastric endoscopic biopsies and surgical removed specimens. The lesional tissues were isolated by Laser Capture Microdissection. Methylation sensitive restriction enzyme (Hpa Ⅱ) digestion and polymerase chain reaction (PCR) were used to detect the clonality at the polymorphic human androgen receptor gene locus on the X chromosome. PCR products were analyzed by capillary electrophoresis using applied Biosystems 3730 DNA Analyzer. In addition, a two-step immunohistochemical staining EnVision method was used to detect the expression of Ki-67 protein. Results The frequency of detection of monoclonality and expression rate of Ki-67 were found increased in a stepwise fashion from gastrointestinal metaplasia, low grade intraepithelial neoplasia, high grade intraepithelial neoplasia to intestinal carcinoma (15. 63% ,5/32; 22.22%, 10/45; 69.44%, 25/36 and 100. 0%, 20/20; respectively). The presence of clonal proliferation was correlated with Ki-67 expression in low grade intraepithelial neoplasia (P<0.01).Conclusions The presence of clonal proliferation and increased Ki-67 are increasingly detected in the lesions along the multi-step gastric carcinogenesis model. Clonal status is associated with the expression rate of Ki-67 to a certain extent, suggesting a combined application of both markers may be useful in assessing early stages of gastric carcinoma.