RER+结直肠癌组织转化生长因子βⅡ型受体的突变

目的　检测转化生长因子 βⅡ型受体 (TGF βRⅡ ) (A) 10 、TGF βRⅡ (GT) 3、TGF βRⅡ 452 /454、TGF βRⅡ 53 3、hMSH3 (A) 8、hMSH6(C) 8、Bax (G) 8、胰岛素样生长因子Ⅱ型受体 (IGFⅡR) (G) 8、IGFⅡR (CT) 3 等微卫星突变热点及TGF βRⅡ点突变在RER 结直肠癌中的突变率、突变发生在肿瘤进程的哪一阶段。方法　采用聚合酶链反应 单链长度多态性分析 (PCR SSLP)、微切割 PCR SSLP、PCR 单链构象多态性分析、克隆测序、免疫组织化学对 76例结直肠癌标本进行分析。结果　RER (replicationerrorpositive)肿瘤TGF βRⅡ (A) 10 突变率约为 3 / 9,突变可发生于重度不典型增生腺瘤。其余位点未见突变。RER 结直肠癌多见于男性 ,发病年龄较早 (P <0 0 5) ;肿瘤多位于结肠 (P <0 0 5)。结论　RER 结直肠癌多见于较年轻男性 ,好发于结肠 ,仅约三分之一病例存在TGF βRⅡ(A) 10 突变 ;TGF βRⅡ (A) 10 突变发生于重度不典型增生腺瘤 ,可能对RER 腺瘤进展为癌起重要作用。RER 结直肠癌在临床病例特征上与西方发达国家的病例存在差异 ,可能有不同的发病机制

Transforming growth factor beta receptor II mutations in RER positive colorectal cancers

OBJECTIVE: To detect alterations of microsatellite loci [transforming growth factor beta receptor II (TGF-betaRII)(A)(10), TGF-betaRII(GT)(3), hMSH3(A)(8), hMSH6(C)(8), Bax(G)(8), IGFIIR(G)(8), IGFIIR(CT)(3)] and point mutations of TGF-betaRII (TGF-betaRII 452/454, TGF-betaRII 533). METHODS: PCR-SSLP, microdissection-PCR-SSLP, PCR-SSCP, clone sequencing and immunohistochemistry were used. RESULTS: The mutation rate of TGF-betaRII(A)(10) in RER+ (replication error positive) colorectal carcinomas was 33% (3/9). Similar mutations were also observed in adenomas with severe dysplasia. No mutations at other microsatellite loci were found. RER+ colorectal cancers mainly occurred in male patients at a young age and were more common in the colon than in the rectum (P < 0.05). CONCLUSIONS: RER+ colorectal cancers were found in young males and commonly located in the colon. A one third mutation rate in TGF-betaRII(A)(10) in these patients is lower than that observed in western populations, which may imply diverse pathways of carcinogenesis of RER+ colorectal carcinoma. TGF-betaRII(A)(10) mutation may play a role in the transforming process from an adenoma with severe dysplasia to a full blown carcinoma.