GENETIC DELETION OF DETOXIFIC ENZYME GSTM1 AND GSTTI AS A HOST SUSCEPTIBLE FACTOR FOR NASOPHARYNGEAL CARCINOMA

Objective: To study the gene polymorphisms of GSTT1 and GSTM1 in nasopharyngeal carcinoma (NPC) patients and controls in an incidental area to evaluate the relationship between specific genotype and genotype combinations of these polymorphisms with the risk of NPC. Methods: Cases and controls all came from the Southwestern Guangxi. DNAs were extracted from their WBC. PCR technique was used to calculate the deletion rate of the two detoxific enzyme genes. Results: In this high risk area of NPC, the residents had high level deletion rates of 47.4% (64/135) Ml and T1 40.7% (55/135). The deletion rates were even higher in NPC patients, 61.5% (56/91) for Ml and 59.3% (54/91) for T1 respectively. There were statistical significances compared with control,P<0.05 andP<0.01 for Ml and T1 respectively. The difference was more significant in terms of combined Ml and T1 deletion between patients and controlsx ²=12.533,P=0.002. Conclusion: The combined deletion of detoxific enzyme genes GSTM1 and GSTT1 may be an important genetic susceptible factor for NPC in Guangxi. Biography: DENG Zhuo-lin (1929-), male, professor of pathology, Guangxi Medical University, majors in tumor pathology. E-mail :zhuolin@hotmail.com     

Methylenetetrahydrofolate Reductase Genotypes, Dietary Habits and Susceptibility to Stomach Cancer

OBJECTIVE To study the relation among methylenetetrahydrofolate reductase (MTHFR) C677T genotypes, dietary habits and the risk of stomach cancer (SC).METHODS A case-control study was conducted with 107 cases of SC and 200 population-based controls in Chuzhou district, Huaian, Jiangsu province, China. The epidemiological data were collected, and DNA of peripheral blood leukocytes was obtained from all of the subjects..MTHFR genotypes were detected by PCR-RFLP. RESULTS (1) The prevalence of the MTHFR C/T or T/T genotypes was found to be significantly different between controls (68.5%) and SC cases (79.4%,P=0.0416), the increased risk had an adjusted OR of 1.79 (95?:1.01-3.19). (2) Among subjects who had a low intake of garlic or Chinese onion, MTHFR C/T or T/T genotypes significantly increased the risk of developing SC. Among non-tea drinkers or among subjects who had a frequent intakeof meat, the carriers of the MTHFR C/T or T/T genotypes had a higher risk of SC than individuals with the C/C type MTHFR. CONCLUSION The polymorphism of MTHFR C677T was associated with increased risk of developing SC, and that individuals with differing genotypes may have different susceptibilities to SC, based on their exposure level to environmental factors.     

诱发食管癌的可能因素

食管癌是人类常见的一种恶性消化道肿瘤。全球男、女平均死亡率分别为25～50／10万和15～25／10万．严重危害着人们的健康。流行病学资料显示．烟、酒是西欧和北美食管癌发生的主要危险因素．而膳食缺乏维生素、亚硝酸盐含量增高以及食物霉菌污染等可能与亚洲中部地区和中国食管癌发生有关。随着分子生物学的发展．发现     

病毒性心肌炎与铁锌的关系及中医治疗

病毒性心肌炎已成为儿童及青年人常见的心脏疾患。机体在铁锌总量不足时，细胞免疫受到损害，防御能力下降，从而对感染的易感性增加。本文对100例病毒性心肌炎病人血清铁锌含量测定与中医治疗进行了相关研究、探讨，现报道如下。     

细胞色素P450 3A4基因多态性及与肝癌易感性研究

目的 探讨细胞色素P450 3A4(CYP3A4)基因的多态性与肝癌的关系。方法 应用聚合酶链反应（PCR）、变性梯度凝胶电泳（DGGE）、单链构象多态（SSCP）和DNA测序技术，对84例肝癌患者和144例健康对照的CYP3A4基因的多态性进行了研究。结果 通过对CYP3A4基因10个外显子的检测，发现2例肝癌患者的第7外显子第15742位核苷酸发生了A→G转换，使得第183位氨基酸残基由天冬酰胺转变为丝氨酸；发现第10内含子存在一单核苷酸多态，表现第20338位核苷酸发生了G→A转换。病例组G／G、G／A和A／A基因型频率分别为59.52％,36.90%和3.58%；对照组则为59.72%，33.33%和6.95％。两组比较没有统计学差异。结论 CYP3A4基因可能高度保守，虽有突变，但属罕见。     

代谢酶基因多态性与胃癌遗传易感性

肿瘤遗传易感性是目前国内外极其关注的研究领域，不同个体对环境致癌物代谢能力的差异决定了个体对肿瘤的易感性。化学致癌物大多为间接致癌物，需经代谢活化后与细胞生物大分子作用而致癌，经解毒酶作用而失活。毒物代谢过程主要包括两类酶：Ⅰ相酶介导氧化代谢，具有活化作用(包括CYP家族)，Ⅱ相酶具有解毒效应(包括GSTs、     

浅谈艾滋病病毒的口腔科门诊传播

艾滋病是一种潜伏期较长的慢性传染病，人群对其易感性高于99％，感染后治疗难度大，病死率高，对人群健康危害极大。目前中国约有84万艾滋病毒感染者，其中只有5％为艾滋病病人，其余95％为病毒携带者，据国内相关机构的调查，去年，全国艾滋病病毒感染者的增长率达到50％，艾滋病防治已经刻不容缓。     

应用DHPLC技术分析错配修复基因(hMLH1)T1151A多态与胃肠道肿瘤的遗传易感性

目的了解中国人hMLH1基因T1151A多态与胃肠道肿瘤的遗传易感性.方法采用病例对照研究设计,提取233例大肠癌(结,直肠癌)患者,273例胃癌患者和268例健康人外周血细胞的基因组DNA.PCR扩增hMLH1基因T1151A多态所在第12外显子的部分DNA片段(217 bp),变性高效液相色谱(DHPLC)检测,DNA测序验证,比较分析T1151A基因型在胃肠道肿瘤的分布.结果正常人群中T1151A多态T/A基因型频率为6.34%,其等位基因A频率为3.28%,在大肠癌患者和胃癌患者中T/A基因型频率与正常人群相比存在显著性差异,分别为11.6%(P=0.039)和12.1%(P=0.021),尤其在＜45岁的大肠癌患者和＜50岁的胃癌患者中,等位基因A频率与正常人群相比差异更为显著,分别为10.66%(P=0.002)和11.27%(P=0.001).结论T1151A作为中国人hMLH1基因上的一个多态位点,可能是中国人大肠癌和胃癌遗传易感因素,可作为中国人胃及大肠肿瘤、尤其是低龄胃及大肠肿瘤高危人群筛选的侯选指标.     

GSTT1基因多态性与中国四川汉族人群肺癌遗传易感性关系的研究

背景与目的GSTs可能参与机体致癌物的解毒反应，如保护个体免受吸烟的损害，因此GSTs基因多态性被认为是个体是否患癌的易感因素。本研究的目的是探讨GSTT1基因多念性与中国四川汉族人群肺癌遗传易感性的关系。方法采用病例对照和PCR—RFLP方法检测中国四川汉族人群肺癌患者150例和健康对照者152例的GSTT1基因缺失型的频率，并评价其与吸烟和肺癌遗传易感性的关系。结果①GSTT1（-）基因型在肺癌组和对照组分别为54．7％(82／150)和38．2％(58/152)．二者间比较有显著性差异(OR=1．681，95％CI=1，009～2．803，P=0．046)；②GSTT1(-)基因型患肺鳞癌(OR=2．969．95％CI=1．511～5．834。P=0．002)及肺腺癌(OR=2．095．95％CI=1．060～4．140，P=0．033)的风险性明显增加；③吸烟者中GSTT1(-)基因型者患肺癌的风险是GSTT1( )者的4．051倍；①GSTT1(-)基因型者中，吸烟者患肺癌的风险是不吸烟者的53．885倍；⑤吸烟≥20包年者中，GSTT1(-)基因型者患肺癌的风险是GSTT1( )者的4．296倍。结论①(GSTT1(-)基因型增加四川汉族人群患肺癌的风险性．特别是增加患肺鳞癌的风险；②GSTT1(-)基因型和吸烟之间存在交互作用，吸烟量越大且为GSTT1(-)基因型者则患肺癌的风险性越大。