【作者】 袁瑛； 郑树； Jae-Gahb Park；

【Author】 Yuan Ying, Jae-Gahb Park, Zheng Shu, Cancer Institute, Zhejiang Medical University, 310009, Cancer Research Institute, Seoul National University College of Medicine

【机构】 浙江医科大学肿瘤研究所； 韩国汉城大学医学院癌研究所；

【摘要】 目的根据本研究组设计的可疑HNPCC参考诊断标准选择可疑HNPCC家系,比较分析符合国际Amsterdam诊断标准的ICG—HNPCC家系和可疑HNPCC家系的分子特征或遗传学背景的异同,评价可疑HNPCC参考诊断的应用价值。该参考诊断标准的具体内容如下:(1)不符合Amsterdam HNPCC诊断标准;(2)家系中有2例或2例以上、经组织病理学明确诊断的大肠癌患者,其中的2例必须是父母和子女的关系或者是同胞兄弟姐妹的关系;和(3)大肠癌患者中至少有1例表现为多发性大肠肿瘤(包括腺瘤),或至少有1例发病早于50岁,或者至少有1个家族成员患有HNPCC相关性大肠外恶性肿瘤。方法每个家系中随机选取一名大肠癌患者为先证者,提取其外周血基因组DNA,用特异性 PCR引物扩增hMLH1和hMSH2基因各个外显子,以SSCP为初步筛选方法,发现异常者用 DNA测序明确突变。结果在29个ICG—HNPCC家系中,有9个家系发现有hMLH1基因的突变,而无一家系含有hMSH2基因的突变,两个基因的总突变率为31.0％(9／29);34个可疑HNPCC家系中。8个家系发现有hMLH1基因的突变,2个家系含有hMSH2基因的突变,两个基因的总突变率为29.4％ (10／34);两组的总突变率相比无显著性差异(P＜0.05),但分别与对照组散发性年青大肠癌的总突变率相比,均有极显著性的差异(P＜0.01)。hMLH1基因是这些韩国家系中的主要相关基因。从突变分析来看,两组的突变均位于基因的后半部分。从突变类型来看,两组中均是以导致短缩蛋白的突变为最常见的类型,其次是错义突变。结论 ICG—HNPCC家系和可疑HNPCC家系有着相似的hMLH1和hMSH2基因的突变情况,提示了两组在分子基础或遗传背景上存在着相似之处,进一步提示了病因学上的相近,可疑 HNPCC参考诊断标准有一定的临床应用价值,可帮助HNPCC家系的临床诊断。更多还原

【Abstract】 Purpose With 29 ICG-HNPCC families and 34 suspected HNPCC families, their molecular characteristics were analysed and compared. All 29 ICG—HNPCC families fulfill the Amsterdam Criteria, while all 34 suspected HNPCC families fit the Criteria for Suspected HNPCC, which was designed in this paper. The detail items of the Criteria for Suspected HNPCC is described as follows: (1) At least 2 pathologically verified colorectal cancers in one family, 2 of them must be siblings or present the vertical transmission of cancer, and (2) At least 1 multiple colorectal tumor (including adenoma) patient, or at least 1 colorectal cancer diagnosed prior to age 50, or at least 1 HNPCC—related extracolonic malignancy in family members. In each fami- ly, a colorectal cancer patient was picked up as the proband of this family. Three results were available described as follows. Methods Genomic DNAs were prepared from peripheral blood samples of probands for the DNA test. PCR—SSCP and DNA sequencing analysis were employed to screen the germline mu- tations of hMLH1 and hMSH2 genes. Results In 29 ICG—HNPCC families, 9 mutations in the hMLH1 gene were detected, while no mutation was found in the hMSH2 gene. The total mutation rate was 31.0％ (9/29). In 34 suspected HNPCC families, 8 mutations in the hMLH1 gene and 2 mutations in the hMSH2 gene were detected. The total mutation rate in this gruop was 29.4％ (10/34), including hMLH1 gene 23.5％ (8/34) and hMSH2 gene 5.9％(2/34). hMLH1 gene was proven to be the main responsi- ble gene in both ICG—HNPCC and suspected HNPCC families, and no obvious difference was found between the mutation rate in the two kinds of families(P＞0.05). As for the muutation type and location, similar characteristics were also detected. Conclusion The similarity of mutation rate, mutation type and mutation location between ICG—HNPCC and suspected HNPCC, suggested the similarity of molecular basis and genetic background between these two groups, and also strongly indicated our Criteria for Suspected HN- PCC is reasonable, and useful in the clinical diagnosis and management of HNPCC.更多还原