结直肠腺瘤中的微卫星不稳定性类型

应用微切割 聚合酶链反应 单链长度多态性 (PCR SSLP)的方法 ,检测 1 6个微卫星位点在 5 9例 6 2个结直肠腺瘤标本的微卫星不稳定性状态 .结果表明 :腺瘤 1 6个位点的总微卫星不稳定性(microsatelliteinstability ,MSI)发生率为 1 4 4 % ,MSI H所占的比率为 9 7% ;在 1 0例可以同时微切割得到腺瘤和癌变成分的病例中 ,腺瘤和癌变成分在每个微卫星位点的改变情况不完全相同 ,并且当在某一位点同时表现为阳性时 ,部分凝胶电泳的图像相同 ,而部分不同 ;在某些位点表现为癌变成分的异常条带泳动速度更快 ,说明序列比腺瘤中更短 ;MSI H与病人的年龄、性别、腺瘤发生部位和病理学亚型之间未见统计学差异 ,但MSI H组的平均年龄 (5 6 5 0± 1 1 38)低于MSI L组 (6 0 36±1 1 34) ,女性所占比率 (5 6 )明显高于男性 ,6例MSI H中无 1例组织学类型为管状腺瘤 ;各位点在MSI H组的MSI改变率明显高于MSI L组 ,在TGFβRⅡ (A) 1 0 、hMSH6、TCF4、BAT2 6等位点有明显差异 (P <0 0 5 ,其中BAT2 6的P <0 0 1 ) .可以推断 :在结直肠癌发生发展的早期即腺瘤阶段即可表现微卫星不稳定性 ;微卫星不稳定性可以随结直肠肿瘤的发展过程而发展 ,并且特定的微卫星位点的改变可能仅发生于肿瘤进程的特定阶段 ;在结直肠癌

Different Types of Microsatellite Instability in Colorectal Adenomas

The MSI status of 16 microsatellite loci of 62 adenoma specimens from 59 patients were detected by means of manual microdissection PCR SSLP. The overall MSI rate of the 16 microsatellite loci was 14 4%, and the frequency of MSI H (microsatellite instability high frequency) was 9 7%. Both adenoma and carcinoma cells were obtained from 10 patients. The MSI status of adenoma and carcinoma at certain loci may be different; and at certain loci carcinoma showed faster shifting bands than adenoma, which meant a shorter microsatellite sequence in carcinoma; There were no significant differences of MSI H with respect to age and sex of patients, or the site and histological subtypes of the adenomas. MSI H patients were younger than MSI L patients (56 50±11 38 vs. 60 36±11 34) and more common in female (5/6) MSI H group was not tubular adenoma histologically; MSI alteration rates at these loci of TGFβRⅡ(A) 10 , hMSH6, TCF4, BAT26 in MSI H group were significantly higher than those in MSI low group ( P <0 05, and P <0 01 as to BAT26). It could be concluded that microsatellite instability existed even in the early stage of colorectal tumorigenesis. MSI could be dynamically changing with the progression of the colorectal tumors, and certain microsatellite alterations might occur only at certain stage of colorectal carcinogenesis. The difference between MSI H and MSI L groups existing in carcinoma is also seen in adenomas. MSI H and MSI L adenomas may be two types of colorectal adenomas.