血管内皮生长因子基因启动子区多态性与血管性痴呆的关系

目的研究血管内皮生长因子（VEGF）基因启动子区多态性与血管性痴呆（VD）发病的关系。方法选择中国北方汉族139例VD患者和150名健康对照者。用直接测序的方法对VEGF基因启动子区测序；用聚合酶链反摩限制性片段长度多态（PCR—RFLP）和直接电泳PCR产物的方法对VEGF基因启动子区多态性进行分型，并对所有标本进行载脂蛋白Ee4（ApoEe4）基因分型，将两组受试者分为携带和不携带ApoEe4基因亚组[ApoEe4（＋）和ApoEe4（-）组]。结果①中国北方汉族人群中的VEGF基因启动子区存在-2578C／A、-2549I／D和-1154G／A三个多态性位点。其中-2578C／A和-2549I／D存在显著的连锁不平衡，-2549I／D位点为18个碱基的插Ⅳ缺失。②多态性位点-2578C／A、-2549I／D的基因型频率、等位基因频率分布，VD组患者和健康对照组间差异无统计学意义（P〉0．05）。经过ApoEe4分层后，VD组和对照组基因型频率、等位基因频率分布差异也无统计学意义。-1154G／A位点，VD组患者的GG基因型频率、G等位基因频率分布明显高于健康对照组（P=0．037，P=0．018）。ApoEe4（-）的亚组中，这种差异同样存在（P=0．021，P=0．010）。用Logistic回归校正年龄、性别和ApoEe4基因后，显示-1154G／A位点GG基因型患者VD的发病风险是AA基因型的1．58倍（OR=1．58，95％CI：1．073—2．338，P=0．020）。（3）ApoEe4（-）的亚组中，-2549I／-1154A单体型在VD组中少于健康对照组（OR=0．536，95％CI．O．328～0．877，P=0．012）。-2549I／-1154G单体型在VD组中明显多于健康对照组（OR=1．785，95％CI：1．018～3．131，P=0．041）。在ApoEe4（＋）的亚组中差异无统计学意义。结论VEGF基因启动子区-1154G／A位点的GG基因型是VD发病的危险因素。此危险因素是独立于ApoEe4基因而影响VD发病的。     

MMP-7基因-181A／G多态性与COPD易感性的相关性研究

目的探讨基质金属蛋白酶7（MMP-7）基因-18lA／G多态性与慢性阻塞性肺疾病（COPD）遗传易感性的关系。方法采用PCR-RELP方法检测100例COPD患者（COPD组）和年龄性别相匹配的100例健康对照者（健康组）MMP-7基因-181A／G多态性等位基因及基因型频率分布情况。结果两组MMP-7基因-181A／G不同位点多态性基因型频率分布均符合遗传性Hardy-Weinberg平街（P均〉0．05）。多态性检测结果显示,COPD组AA、AG和GG基因型频率分别为17％、48％和35％,健康组分别为18％,70％和12％,两组不同基因型频率分布有统计学意义（P=0．05）;COPD组G等位基因频率显著健康组（P=0．006）。结论MMP-7基因-180A／G多态性可能与COPD遗传易感性增加有关,G等位基因可能是COPD的易感基因。     

高血压病患者阿司匹林抵抗与β纤维蛋白原基因启动子区-455G／A多态性的关系

目的探讨高血压患者β纤维蛋白原基因启动子区-455G／A多态性与阿司匹林抵抗的关系。方法用电阻抗法测定108例高血压患者口服阿司匹林前后ADP及花生四烯酸诱导的血小板聚集电阻抗值（ohm）,判定患者阿司匹林疗效,分为阿司匹林敏感、环氧化酶型阿司匹林抵抗,环氧化酶旁路型阿司匹林抵抗;用聚合酶链反应-限制性片段长度多态性（PCR—RFLP）方法检测βFg基因启动子区-455G／A多态性,依据多态性结果分为GG基因组和GA＋AA基因组,比较不同基因组纤维蛋白原浓度以及阿司匹林抵抗发生率。结果高血压患者GG、GA、AA基因型频率分别为0．639、0．324、0．037,G、A等位基因频率分别为0．801、0．199。GA＋AA组纤维蛋白原浓度高于GG组（3．30±0．98vs2．93±0．70,p〈0．05）。环氧化酶型阿司匹林抵抗发生率GG组、GA＋AA组分别为13．04％、7．69％（Х^2=0．282,p〉0．5）;环氧化酶旁路型阿司匹林抵抗发生率GA＋AA组显著高于GG基因组（61．54％vs34．78％,Х^2=5．841,p=0．016）。结论βFg基因-455G／A启动子区携带A-455等位基因高血压患者环氧化酶旁路型阿司匹林抵抗发生率高,A-455等位基因与环氧化酶旁路型阿司匹林抵抗具有相关性。     

CD86基因启动子－3479 A／C 位点单核苷酸多态性与 ITP 遗传易感性的关系

目的：探讨CD86基因启动子－3479 A／C位点（ rs2715267）单核苷酸多态性与原发免疫性血小板减少症（ ITP）遗传易感性的关系。方法收集93例成人慢性ITP患者（ ITP组）及119例健康对照者（对照组）,提取两组外周血DNA,采用位点特异性PCR进行DNA分型检测。分型结果通过DNA测序方法进行验证。结果 CD86基因启动子－3479 A／C位点基因型AA、AC和CC在ITP组的分布频率分别为40．9％、52．6％及6．5％,在对照组的分布频率分别为49．6％、37．8％及12．6％,两组比较P 均＞0．05;等位基因A和C在ITP组的分布频率分别为67．2％、32．8％,在对照组的分布频率分别为68．5％、31．5％,两组比较P均＞0．05。两组同性别CD86基因启动子－3479 A／C位点等位基因及基因型的分布频率比较P均＞0．05。根据糖皮质激素治疗效果将ITP患者进行分组,结果显示,激素有效组、激素无效组CD86基因启动子－3479 A／C位点等位基因及基因型的分布频率比较P均﹥0．05。结论 CD86基因启动子－3479 A／C位点的单核苷酸多态性可能与ITP的遗传易感性无关。     

凝血酶活化纤维蛋白溶解抑制物基因编码区G505A单核苷酸多态性与脑梗死的关系

目的探讨中国汉族人群中凝血酶活化纤维蛋白溶解抑制物（TAFI）基因编码区G505A单核苷酸多态性与脑梗死的关系。方法采用聚合酶链反应一限制性片段长度多态性（PCR-RFLP）技术,检测130例脑梗死患者和118例同期体检者的TAFI基因编码区G505A的多态性。结果脑梗死组TAFI基因G505A的GG基因型占35．4％（46／130）,GA＋AA基因型占64．6％（84／130）;而对照组分别为49．2％（58／118）、50．8％（60／118）,差异有统计学意义（P=0．028）。脑梗死组G、A等位基因频率分别为60．4％（157／260）、39．6％（103／260）,对照组分别为69．9％（165／236）,30．1％（71／236）,差异有统计学意义（P=0．026）。多因素Logistic回归分析显示,TAFI基因编码区G505A单核苷酸多态性（GA或AA基因型）是脑梗死发病的独立危险因素（OR=2．660,95％CI：1．330-5．317,P=0．006）。结论TAFI基因G505A的多态性可能是脑梗死的危险因素之一。     

CTLA-4基因启动子区-1661和-318位点多态性与胃癌的关系

细胞毒性T淋巴细胞相关抗原4（CTLA-4）是一种免疫调节分子,可通过降低T细胞活性,抑制机体的抗肿瘤免疫反应。目的：探讨CTLA-4基因启动子区-1661和-318位点多态性与胃癌的关系。方法：121例无血缘关系的胃癌患者和236名正常对照者纳入研究,分别采用聚合酶链反应一限制性片段长度多态性（PCR—RFLP）和扩增不应突变系统（ARMS）。PCR检测CTLA-4基因启动子区-1661和．318位点多态性。结果：胃癌组．1661位点AA基因型和A等位基因频率显著低于正常对照组（73．6％对83．9％,P=0．024;85．1％对91．1％,P=0．022）;而-318位点CC基因型和C等位基因频率与正常对照组相比无明显差异。管状腺癌患者CTLA-4基因启动子区-1661位点AA基因型和．318位点CC基因型频率显著低于正常对照组（64．1％对83．9％,P=0．001;76．6％对87．3％,P=0．047）。结论：CTLA-4基因启动子区-1661位点基因多态性与胃癌呈显著负相关,-1661和-318位点多态性与管状腺癌呈显著负相关。     

IL-6基因启动子区-634C/G多态性与糖尿病肾病的相关性

目的 探讨白细胞介素6（IL-6）基因启动子区-634C／G多态性与糖尿病肾病（DN）的关系。方法 在昆明地区汉族人中，应用PCR—RFLP方法和等位特异PCR（ASPCR）方法，对246例2型糖尿病（T2DM）患者（正常白蛋白尿组88例，微量白蛋白尿组93例，大量白蛋白尿组65例）和101例健康对照者（NC组）的IL-6基因启动子区-634C／G多态性进行检测。结果 （1）微量白蛋白尿组、大量白蛋白尿组、微量、大量白蛋白尿组的G／G基因型频率均高于正常白蛋白尿组（P=0．001），大量白蛋白尿组亦高于微量白蛋白尿组（P=0．045）。（2）大量白蛋白尿组和大量、微量白蛋白尿组的G等位基因频率均高于正常白蛋白尿组（P=0．031），大量白蛋白尿组亦高于微量白蛋白尿组（P=0．005）。（3）T2DM组中，GG基因型组UAER明显高于CG、CC基因型组（P〈0．01）。（4）Logistic回归分析表明：IL-6基因启动子区-634G／G基因型、病程是DN发生的危险因素。结论在昆明地区汉族人中，IL-6基因启动子区-634G／G基因型可能是DN发生的危险因素，此基因型携带者UAER明显增高；G等位基因可能是DN发展的危险因素之-。     

单核细胞趋化蛋白-2518G/A基因多态性与冠心病的关系

目的研究单核细胞趋化蛋白-1（MCP-1）-2518G／A基因多态性对冠心病发病的影响。方法选取冠心病患者300例,正常对照组60例。冠心病患者分急性冠状脉综合征（ACS）组180例以及稳定型心绞痛（SAP）组120例。所有患者行冠状动脉造影（CAG）检查,采用Gensini评分。酶联免疫法测定MCP-1浓度,PCR-RFLP方法检测MCP-1-2518G／A位点多态性,研究MCP-1-2518G／A基因多态性与冠心病的相关性。结果（1）MCP-1-2518G／A基因多态性ACS组GG型基因和G等位基因频率分布较SAP组及正常对照组升高[GG型基因：ACS组（33．4％）,SAP组（24．2％）,对照组（15．0％）。P〈0．05;G等位基因频率：ACS组（51．1％）,SAP组（40．4％）,对照组（31．7％）,P〈0．05],ACS组AA型基因及A等位基因较SAP组及正常对照组降低[AA型基因：ACS组（31．1％）,SAP组（43．3％）,对照组（51．7％）,P〈O．05;A等位基因频率：ACS组（48．9％）,SAP组（59．6％）,对照组（68．3％）,P〈0．05]。（2）三种基因型间MCP．1浓度比较,GG型MCP-1浓度较AG型及AA型升高[GG型基因：（153±22）ng／L,AG型基因：（136±18）ng／L,AA型基因：（124±15）ng／L,（P〈0．05）]。（3）多元回归分析冠脉病变Gensini评分与低密度脂蛋白-胆固醇、空腹血糖、MCP-1GG型基因成正相关（P〈0．05）,高密度脂蛋白-胆固醇与冠状动脉狭窄程度呈负相关（P〈0．05）。结论MCP-1-2518G／A基因多态性与冠心病严重程度相关;MCP-1-2518G／A基因多态G等位基因能通过增强MCP-1表达参与冠心病发病。     

急性脑梗死患者IL-18基因启动子607C／A、137G／C位点多态性观察

目的观察急性脑梗死患者白细胞介素18（IL-18）基因启动子607C／A和137G／C位点单核苷酸多态性（SNP）。方法采用型特异性引物聚合酶链反应（PCR-SSP）技术检测98例脑梗死患者（观察组）和100例健康对照者（对照组）血清IL-18基因启动子607C／A和137G／C位点多态性。结果两组607C／A位点基因型CC、CA和AA的频率及等位基因频率相比P均〉0．05。观察组组137G／C位点GG型频率显著高于对照组,GC型的频率显著低于对照组（P〈0．05）,两组等位基因频率的分布也有显著性差异（P〈0．05）。结论急性脑梗死患者IL-18基因启动子607C／A位点SNP与脑梗死无关,137G／C位点携带等位基因C可能有预防急性脑梗死的作用。     

内皮素转化酶1启动子区T-839G基因多态性与颈动脉粥样硬化的相关性

目的研究内皮素转化酶1（ECE-1）启动子T-839G基因多态性与颈动脉粥样硬化的相关性。方法选择经DSA或CTA、MRA诊断的颈动脉粥样硬化患者及与之年龄和性别相匹配的对照者,各518例。采用多聚酶链反应-限制性片段长度多态性（PCR—RFLP）的方法检验ECE-1启动子区T-839G基因多态性。结果两组TT、TG、GG基因型分布差异无统计学意义（χ^2=4．674,P〉0．05）,颈动脉粥样硬化组等位基因频率T略高于对照组（92．3％,89．8％）,G略低于对照组（7．7％,10．2％）,差异有统计学意义（χ^2=3．993,P〈0．05）。两组总计（GG＋TG）／TT的基因型频率差异虽无统计学意义,但按性别和年龄分层后,显示女性和〈64岁者（GG＋TG）／TT基因型频率对照组均高于颈动脉粥样硬化组（女性：OR=0．59;95％CI：0．37～0．94;P=0．03。〈64岁者：OR=0．61;95％CI：0．38～0．97;P=0．04）结论ECE-1启动子区T-839G多态位点G等位基因可能降低女性及年龄〈64岁者颈动脉粥样硬化发生的危险性。     

Extensive methylation of hMLH1 promoter region predominates in proximal colon cancer with microsatellite instability.

BACKGROUND & AIMS: Methylation of the hMLH1 promoter region has been suggested to cause microsatellite instability (MSI) in sporadic colorectal carcinoma (CRC). We studied the methylation profile in a wide region of the hMLH1 promoter and compared with the hMLH1 protein expression and MSI status in 88 cases of sporadic CRC. METHODS: Na-bisulfite treatment and polymerase chain reaction single-strand conformation polymorphism analysis was performed using 5 sets of polymerase chain reaction primers spanning the promoter region of the hMLH1 to examine methylation status. Results were compared with immunostaining using anti-hMLH1 monoclonal antibody and MSI status of the tumor samples. RESULTS: Methylation status was classified as full or partial methylation. Full methylation indicates the methylation of all CpG sites in the examined regions. Methylation of the hMLH1 promoter was observed in 88.9% (16 of 18) of CRCs showing high frequency MSI (MSI-H), among which 89% (14 of 16) had full methylation with reduced hMLH1 protein expression. All cases showing full methylation were proximal colon tumors with MSI-H. In cases with partial methylation, only the upstream region of the hMLH1 promoter was methylated. Partial methylation was also shown in 33.3% (6 of 18) of the normal mucosa of MSI-H cases. Frequencies of methylation were significantly correlated with female gender (P = 0.0009) and aging (P = 0.007). CONCLUSIONS: Full methylation of the hMLH1 promoter region and subsequent gene inactivation may play a crucial role in the carcinogenesis of MSI-H CRCs in the proximal colon. Methylation upstream of the hMLH1 promoter appears to be an early event in the carcinogenesis of MSI-H tumors.     

Clinical features and mismatch repair gene mutation screening in Chinese patients with hereditary nonpolyposis colorectal carcinoma

AIM: Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominantly-inherited cancer-susceptibility syndrome that confers an increased risk for colorectal cancer and a variety of other tumors at a young age. It has been associated with germline mutations in five mismatch repair (MMR) genes (hMSH2, hMLH1, hPMS1, hPMS2, and hMSH6/GTBP). The great majority of germline mutations were found in hMSH2 and hMLH1. The purpose of this study was to analyze the clinical features of Chinese HNPCC patients and to screen hMSH2 and hMLH1 gene mutations. METHODS: Twenty-eight independent Chinese families were collected, of which 15 met Amsterdam criteria I and 13 met the Japanese clinical diagnosis criteria. The data were recorded including sex, site of colorectal cancer (CRC), age of diagnosis, history of synchronous and/or metachronous CRC, instance of extracolonic cancers, and histopathology of tumors. Peripheral blood samples were collected from all pedigrees after formal written consents were signed. PCR and denaturing high-performance liquid chromatography (DHPLC) were used to screen the coding regions of hMSH2 and hMLH1 genes. The samples showing abnormal DHPLC profiles were sequenced by a 377 DNA sequencer. RESULTS: One hundred and seventy malignant neoplasms were found in one hundred and twenty-six patients (multiple cancer in twenty-three), including one hundred and twenty-seven CRCs, fifteen gastric, seven endometrial, and five esophageal cancers. Seventy-seven point eight percent of the patients had CRCs, sharing the features of early occurrence (average age of onset, 45.9 years) and of the right-sided predominance reported in the literature. In Chinese HNPCC patients, gastric cancer occurred more frequently, accounting for 11.9% of all cancers patients and ranking second in the spectrum of HNPCC predisposing cancers. Synchronous CRCs occurred less frequently, only accounting for 3.1% of the total CRCs. Twenty percent of the colorectal patients had metachronous CRCs within 10 years after operation. Eight hMSH2 or hMLH1 gene sequence variations were found in twelve families, including the first Mongolian kindred with a hMSH2 gene mutation. CONCLUSION: HNPCC is characterized by an early-age onset, proximal predominance of CRC, multiple metachronous CRCs, and an excess of extra-colonic cancers. Frequent gastric cancer occurrence and less synchronous CRCs are the remarkable features in Chinese HNPCC patients. DHPLC is a powerful tool in hMSH2 and hMLH1 gene mutation screening. hMLH1 gene mutations, especially of the first nine exons, have been found more common than hMSH2 gene mutations in Chinese patients. Three of seven mutations have been found to be novel, and the germline G204X nonsense mutation in the third exon of hMSH2 has become the first MMR gene mutation found in Chinese Mongolian people.     

Mutational analysis of the DNA mismatch repair gene hMLH1 in myeloid leukaemias

Mutations of the DNA mismatch repair (MMR) gene hMLH1 have recently been linked to the development of some hereditary and sporadic cancers which frequently display widespread microsatellite instability (MSI). Conflicting results regarding the extent of MSI in myeloid leukaemias prompted us to perform mutational analysis of all 19 exons of the hMLH1 gene by polymerase chain reaction-single-stranded conformation polymorphism (PCR-SSCP) and sequence analysis in a total of 133 patients with acute and chronic myeloid leukaemia. Apart from one exonic and one intronic polymorphism, no mutations were detected in any of the samples indicating that the major MMR gene hMLH1 is not involved in the pathogenesis or progression of myeloid malignancies.     

Association between family history and mismatch repair in colorectal cancer

BACKGROUND AND AIMS: Germline mutations in mismatch repair (MMR) genes cause a greatly increased risk of cancer of the gastrointestinal and female reproductive tracts (hereditary non-polyposis colorectal cancer (HNPCC)). Loss of MMR expression is common in colorectal cancer (CRC) overall. Such loss is assumed to be acquired predominantly, although a population of CRC cases will include individuals with unrecognised MMR mutations. This study examines the association between MMR gene expression and family history of cancer among the CRC population. METHODS: Individuals with CRC were identified from two well characterised populations: (1) consecutive hospital patients (n = 644) and (2) a population based cases series (n = 249). CRC was examined for expression of hMLH1 and hMSH2 using immunohistochemistry, and expression was related to family history using logistic regression. RESULTS: hMLH1 and hMSH2 expression was assessed in 732 CRCs with 8% showing loss of expression. No association was seen overall for hMLH1 or hMSH2 expression and family history of CRC. Loss of hMSH2 was predicted by family history of extracolonic cancer (odds ratio (OR) 5.78 (95% confidence interval (CI) 0.95-35.18)) and family history suggestive of HNPCC (OR 27.84 (95% CI 4.37-177.56)). Loss of hMLH1 was not predicted by family history of extracolonic cancer or a family history suggestive of HNPCC but was for a family history of at least two affected relatives (OR 4.88 (95% CI 1.25-19.03)). CONCLUSIONS: Individuals with hMSH2 deficient CRC in the general population exhibit a family history and other characteristics suggestive of HNPCC, and may carry germline MMR mutations. Loss of hMLH1 is only associated with a strong family history of extracolonic cancer at older ages, suggesting a novel mechanism of susceptibility.     

Tobacco use and increased colorectal cancer risk in patients with hereditary nonpolyposis colorectal cancer (Lynch syndrome)

BACKGROUND: The marked variability in age at onset of colorectal cancer (CRC) in patients with hereditary nonpolyposis colorectal cancer (HNPCC) makes management decisions difficult. Environmental factors governing the phenotypic variability of cancer-associated syndromes such as HNPCC have not been elucidated. METHODS: We determined whether tobacco use would alter CRC risk in carriers of HNPCC-associated mutations, using a retrospective cohort study of germline mutation (hMLH1 or hMSH2) carriers from the Hereditary Cancer Institute at Creighton University, one of the oldest and largest registries of HNPCC patients. The main outcome measure was age at CRC onset, estimated by means of Cox proportional hazards modeling. RESULTS: Tobacco use, hMLH1 mutation carriage (as opposed to hMSH2), and male sex were significantly associated with increased risk of CRC (hazard ratios, 1.43, 2.07, and 1.58, respectively). Alcohol use did not alter CRC risk. CONCLUSIONS: Smoking cessation should be an integral part of HNPCC management. This study underscores the gene x environment interactions in cancer development.     

Frequency of hereditary non-polyposis colorectal cancer in Danish colorectal cancer patients.

BACKGROUND: Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant cancer syndrome, characterised by familial aggregation of HNPCC related cancers, germline mutations in mismatch repair genes, and/or microsatellite instability (MSI) in tumour tissue. AIM: To estimate the frequency of HNPCC among non-selected Danish patients with colorectal cancer (CRC), and to evaluate the value of MSI analysis as a pre-screen test. METHODS: This was a prospective population based study on consecutive CRC patients. A family history of malignancy was obtained and suspected HNPCC cases were screened for hMLH1/hMSH2 mutations and subjected to MSI analysis. Patients with germline mutations and/or those with Amsterdam criteria I or II families were categorised as HNPCC patients. RESULTS: Among 1328 eligible CRC patients, 1200 (90.4%) completed a questionnaire. A total of 1.7% (95% confidence interval (CI) 1.0-2.4) (20 cases) were categorised as HNPCC patients. Amsterdam criteria I or II were met in 18 cases (1.5%), and in another two cases (0.2%) pathogenic hMLH1/hMSH2 mutations were detected without fulfillment of the Amsterdam criteria I or II. Among 77 patients younger than 50 years of age, 11 cases (14.3%) were categorised as HNPCC. The Amsterdam criteria I or II were met in eight of 10 gene carriers (80%). The MSI-high phenotype was demonstrated in all 10 gene carriers. CONCLUSION: The frequency of HNPCC was approximately 1.7% among all CRC cases and 14.3% among patients younger than 50 years of age. MSI analysis is a reliable pre-screen test for hMLH1/hMSH2 mutations in families suspected of having HNPCC.     

Susceptibility to refractory ulcerative colitis is associated with polymorphism in the hMLH1 mismatch repair gene

The hMLH1 gene lies in the linkage susceptibility region to inflammatory bowel disease (IBD) on 3p21. A single nucleotide polymorphism, 655A>G, in exon 8 of the gene causes an I219V change in the MLH1 protein. To test whether hMLH1 may confer susceptibility to ulcerative colitis (UC), we investigated an association between the 655A>G polymorphism and the disease. DNA-based technologies were used to analyze the 655A>G polymorphism in 201 UC patients and 126 healthy ethnically matched controls. The comparison of the allelic frequencies of the 655A>G polymorphism in UC patients and healthy controls did not show significant differences. However, genotype frequencies at the hMLH1 655 position were found to be significantly different when patients with and without refractory UC were compared. This was mainly attributable to a higher level of homozygosity for the G allele in refractory UC patients. Almost 5 times as many (4.9 times) refractory UC patients carried the GG genotype compared with nonrefractory patients (P < 0.0001). The present study provides evidence that the hMLH1 gene is involved in genetic susceptibility to refractory UC. If confirmed by other studies, the GG genotype at position 655 of the hMLH1 gene may represent a useful predictive factor for the clinical management of UC patients.     

Clinical and molecular analysis of hereditary non-polyposis colorectal cancer in Chinese colorectal cancer patients

AIM:To analyze the frequency of hereditary non-polyposis colorectal cancer(HNPCC)in Chinese colorectal cancer(CRC)patients,and to discuss the value of microsatellite instability(MSI)and/or immunohistochemistry(IHC)for MSH2/MLH1 protein analysis as pre-screening tests in China.METHODS:The Amsterdam criteriaⅠandⅡ(clinical diagnosis)and/or germline hMLH1/hMSH2 mutations(genetic diagnosis)were used to classify HNPCC families.Genetic tests,including microsatellite instability,immunohistochemistry for MSH2/MLH1 proteins and hMSH2/hMLH1 genes,were performed in each proband.RESULTS:From July 2000 to June 2004,1988 patients with colorectal cancer were analysed and 114 CRC patients(5.7%)from 48 families were categorized as having HNPCC,including 76 from 26 families diagnosed clinically and 38 from the other 22 families diagnosed genetically.The sensitivity and specificity of high MSI and IHC for predicting mutations were 100% and 54%,and 79% and 77%,respectively.CONCLUSION:The frequency of HNPCC is approximately 10% among all Chinese CRC cases.The MSI and IHC detections for hMSH2/hMLH1 proteins are reliable pre-screening tests for hMLH1/hMSH2 germline mutations in families suspected of having HNPCC.     

Rapid diagnostic test for hereditary nonpolyposis colon cancer kindred using polymerase chain reaction

PURPOSE: We have identified a mutation in thehMLH1 gene from the proband of a hereditary nonpolyposis colorectal cancer kindred. We wished to develop a rapid test for this specific mutation to facilitate screening of other family members. METHOD: An allele-specific polymerase chain reaction strategy was used to detect a T insertion at the +3 splice site post exon 9 in thehMLH1 gene. The test was evaluated on DNA in which the mutation status was known. RESULTS: A 130-base pair fragment was reliably amplified using the allele-specific polymerase chain reaction. The test is able to identify the mutant allele and to distinguish between normal, carriers (heterozygous), and tumor DNA samples. The mutant allele is not present in an unrelated hereditary nonpolyposis colorectal cancer cell line or in a sample of the normal population (n=49). CONCLUSIONS: This is a simple, rapid test that can determine carrier status in the members of a kindred at risk for this mutation. This mutation is unlikely to be a polymorphism. This test may now be evaluated in a clinical setting.Ian Faragher is in receipt of a National Health and Medical Research Council medical postgraduate scholarship, Canberra, Australia.     

Risk of colon cancer in hereditary non-polyposis colorectal cancer patients as predicted by fuzzy modeling： Influence of smoking

AIM: To investigate whether a fuzzy logic model could predict colorectal cancer (CRC) risk engendered by smoking in hereditary non-polyposis colorectal cancer (HNPCC) patients. METHODS: Three hundred and forty HNPCC mismatch repair (MMR) mutation carriers from the Creighton University Hereditary Cancer Institute Registry were selected for modeling. Age-dependent curves were generated to elucidate the joint effects between gene mutation (hMLH1 or hMSH2), gender, and smoking status on the probability of developing CRC. RESULTS: Smoking significantly increased CRC risk in male hMSH2 mutation carriers (P < 0.05). hMLHl mutations augmented CRC risk relative to hMSH2 mutation carriers for males (P < 0.05). Males had a significantly higher risk of CRC than females for hMLHl non smokers (P < 0.05), hMLHl smokers (P < 0.1) and hMSH2 smokers (P < 0.1). Smoking promoted CRC in a dose-dependent manner in hMSH2 in males (P < 0.05). Females with hMSH2 mutations and both sexes with the hMLHl groups only demonstrated a smoking effect after an extensive smoking history (P < 0.05). CONCLUSION: CRC promotion by smoking in HNPCC patients is dependent on gene mutation, gender and age. These data demonstrate that fuzzy modeling may enable formulation of clinical risk scores, thereby allowing individualization of CRC prevention strategies.