Investigation of possible involvement of several genes related to development of hepatocarcinogenesis in rats

A comparative study on the possible involvement of several genes in the susceptibility of chemical carcinogenesis was carried out using carcinogen-resistant DRH rat and -sensitive Donryu and F344 rats. Previously, we observed that the induction of glutathione S-transferase placental form (GST-P) in the liver of Donryu rats by 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) was significantly greater than that of DRH rats. In the present study, we tentatively determined base sequences of the enhancer region including GPE-I and GPE-II (GST-P enhancers I and II) of GST-P genes of DRH, Donryu and F344 rats, but we did not observe any nucleotide polymorphism around these regions. Furthermore, the mRNA levels of silencer binding protein (NFA-1) for the GST-P promoter of rat liver were also similar in the DRH and Donryu rats. Since clonal expansion of putative preneoplastic GST-P-positive foci in the DRH rat liver was significantly suppressed during 3'-Me-DAB administration, we examined whether two opposite growth controlling factors, TGF-alpha and TGF-beta, may participate in such suppression of growth. It was supposed that mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R), at least in part, activates TGF-beta preproprotein. However, we observed that the levels of M6P/IGF2R mRNA in the livers of DRH were not higher than those of Donryu rats after being fed 3'-Me-DAB for 8 weeks. Another important factor in the carcinogenesis is insulin-like growth factor II itself. Although liver tumors induced by 3'-Me-DAB in F344 had high levels of IGF-II mRNA, little IGF-II gene expression existed in normal adult livers of Donryu, F344 and DRH rats. High levels of IGF-II mRNA were detected similarly in the livers of neonates from all these three strains of rats. Finally, we detected a significant increase of AFP (alpha-fetoprotein) mRNA in the livers of Donryu rats around 6 to 8 weeks from the start of 3'-Me-DAB feeding, which is in parallel with detrimental effects of this carcinogen on these rats. A reduced induction of AFP mRNA was observed in DRH rats under the same conditions. Further study will be needed to explain the lower tumor susceptibility in the DRH rat.     

Studies on the multidrug resistance gene expression in the livers of rats associated with different susceptibility of hepatocarcinogenesis

Inbred carcinogen-resistant DRH rat strain developed from the closed colony Donryu rats on the basis of selective markers such as poor induction of gamma-glutamyltranspeptidase and marked reduced incidences of liver tumors during 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) administration, which took more than 10 years. Previously, we observed that the Donryu rat liver was quite sensitive to both DNA-damaging and cytotoxic effects of 3'-Me-DAB, while the DRH rat liver showed tolerance to 3'-Me-DAB under the same conditions. In the present study, we examined mRNA levels related to the cytotoxic drug resistance mechanism in the livers of DRH and Donryu rats using RT-PCR. Contrary to our expectation, we observed rather similar levels of mRNAs between the two rat strains under the following conditions: i) mdr1 mRNA induction after 3'-Me-DAB administration. ii) MLP-2 mRNA reduction by 3'-Me-DAB administration, iii) MLP-2 mRNA induction after cholestasis and iv) constitutive levels of cMOAT gene expression. On the other hand, the levels of p53 mRNA and p53 protein in the Donryu rat liver were higher than those in DRH rat liver during 3'-Me-DAB administration, suggesting that the former were more sensitive to 3'-Me-DAB than DRH rat under these conditions. In conclusion, we failed to demonstrate the difference in the cytotoxic drug resistance mechanism between DRH and Donryu rats at least under the conditions examined in this study.     

镍化合物诱发细胞恶变过程中的P53基因的变化

目的 探讨三种镍化合物在诱发细胞恶变过程中不同阶段P53基因突变情况，并比较它们之间的差异。方法 三种镍化合物转化细胞接种BALB／c裸鼠，应用PCR－SSCP进行肿瘤细胞和转化细胞P53基因第5－8外显子检测。结果 硫化镍组一个经软琼脂筛选的转化细胞系和相应的肿瘤细胞系P53基因第8外显子检出突变。氯化镍组的肿瘤细胞系第6外显子检出突变。结论 本文说明了镍化合物诱导细胞恶变的晚期发生P53基因突变。     

食管癌P53基因第5外显子突变分析

目的　分析不同地区食管癌组织中 p5 3基因第 5外显子的突变谱。 方法　采用PCR扩增产物纯化后直接DNA序列测定技术对陕西省西安市 4 2例和河南省林州市 4 3例食管癌标本 p5 3基因第 5外显子突变情况进行检测。结果　西安和林州市食管癌标本中 p5 3基因第 5外显子突变率分别为 14 3% (6 /42 )和 18 6 % (9/43) ,两地突变率比较差异无统计学意义 (P >0 0 5 )。西安 6个突变位点中 4个为点突变 ,2个为缺失突变 ;林州 10个突变位点中9个为点突变 ,1个为插入突变。西安市有 4例突变发生在 12 6～ 12 8位点 ,林州市仅有 2例发生在该区域 (2 /10 ) ,但两者相比差异无统计学意义 (P >0 0 5 )。结论　西安市食管癌 p5 3基因第 5外显子的突变位点相对集中 ,林州市突变位点比较分散 ,可能与该地区多种危险因素的暴露有关。     

Assessment of the mutations of p53 suppressor gene and Ha- and Ki-ras oncogenes in malignant mesothelioma in relation to asbestos exposure: a study of 12 American patients

In our previous study, we found no genetic alteration in exons 1 and 2 of Ha- and Ki-ras oncogenes nor in exons 5 to 9 of the p53 suppressor gene in seven Japanese malignant mesothelioma patients exposed to asbestos. To examine further whether malignant mesothelioma due to asbestos has genetic alterations in the p53 suppressor gene and in Ha- and Ki-ras oncogenes, we analyzed point mutations of these genes in paraffin embedded operative open biopsied samples of the primary tumor of malignant mesothelioma in twelve American patients. The genetic analysis was conducted by the PCR-SSCP (polymerase chain reaction single-strand conformation polymorphism) method in all patients and by sequencing analysis of DNA bases in the two patients with suspected gene mutation. The analysis of the p53 suppressor gene showed an amino acid converting mutation of exon 7 in one patient and a polymorphism of exon 6 in another patient; the former patient was a heavy smoker with a biphasic cell type. No genetic alteration was found in exons 1 and 2 of Ha- and Ki-ras oncogenes in any of the patients. The results suggest that the effects of asbestos on the p53 suppressor gene and Ha- and Ki-ras oncogenes in malignant mesothelioma are negligible. Further studies are needed to examine whether the observed mutation of the p53 suppressor gene is due to the combined effects of asbestos and smoking or to other unknown factors.     

p53基因甲基化和突变与燃煤污染型砷中毒关系研究

目的 探讨燃煤砷污染对人体p53基因甲基化(启动子区及第5外显子)和突变(第5外显子)的影响,分析其与燃煤型砷中毒的关系.方法 在贵州省兴仁县燃煤型砷中毒病区选择112例砷中毒患者,根据病情将其分为轻度中毒组(38例)、中度中毒组(43例)和重度中毒组(31例);根据有皮肤病理学诊断患者(43例)的病理结果,将其分为非癌变组(24例)和癌变组(19例).选择条件相似的非砷暴露村90名居民作为对照组.在知情同意原则下,采集上述观察对象的外周血,应用限制性内切酶-PCR法检测p53基因启动子区及第5外显子甲基化情况,应用PCR-单链构象多态性技术及PCR产物克隆测序技术检测p53基因第5外显子突变情况.结果 p53基因启动子区甲基化阳性率在轻、中、重度组分别为13.16%(5/38)、27.91%(12/43)、45.16%(14/31),与对照组[1.11%(1/90)]比较差异均有统计学意义(χ2值分别为8.679、23.690、41.199,P值均＜0.017);在非癌变组和癌变组分别为25.00%(6/24)和63.16%(12/19),与对照组[1.11%(1/90)]比较差异均有统计学意义(χ2值分别为18.762、57.497,P值均＜0.025).p53基因第5外显子甲基化阳性率在轻、中、重度组分别为55.26%(21/38)、51.16%(22/43)、48.39%(15/31),与对照组[88.88%(80/90)]比较差异有统计学意义(χ2值分别为18.151、23.168、22.420,P值均＜0.017);在非癌变组和癌变组分别为54.17%(13/24)和42.11%(8/19),与对照组[88.88%(80/90)]比较差异有统计学意义(χ2值分别为15.201、22.075,P值均＜0.025).p53基因第5外显子突变率在轻、中、重度组分别为5.26%(2/38)、16.28%(7/43)、25.81%(8/31),中、重度组与对照组(0.00%)比较差异均有统计学意义(χ2值分别为15.465、24.870,P值均＜0.017);在非癌变组和癌变组分别为16.67%(4/24)、31.58%(6/19),与对照组(0.00%)比较差异均有统计学意义(χ2值分别为15.545、30.077,P值均＜0.025).启动子区高甲基化与第5外显子突变相关(列联系数为0.294,P＜0.05);第5外显子低甲基化与第5外显子突变相关(列联系数为0.410,P＜0.05).结论 燃煤砷污染可致人体p53基因启动子区高甲基化、第5外显子低甲基化和突变,上述甲基化改变均与p53基因突变相关联;p53基因甲基化改变可能是砷致p53基因突变以及砷致病或致癌的重要原因之一.

Abstract：

Objective To explore the influence of arsenic pollution caused by coal-burning on methylation(promoter and exon 5 ) and mutation (exon 5 ) of human p53 gene, and to analyze the relationship between methylation, mutation and arsenism. Methods According to the diagnostic criteria of endemic arsenism, 112 patients with arsenism (including 38 mild cases,43 moderate cases and 31 severe cases) were selected in the areas with endemic arsenism from Xingren, Guizhou province. Among the subjects ,43 cases were diagnosed by dermatopathological methods, and they were divided into non-cancerous group (24 cases) and cancerous group ( 19 cases ). 90 controls were selected from the non-arsenic polluted areas. Under the principle of informed consent, blood samples were collected from individuals. The methylation of p53 gene in promoter region and exon 5 were detected by extinction enzyme-PCR,the mutation of p53 gene (exon 5 ) was detected by PCR-SSCP,PCR products cloning and sequencing technology. Results The positive rates of methylation of p53 gene in promoter region were 13. 16% ( 5/38 ), 27.91% ( 12/43 )and 45. 16% (14/31) respectively among mild, moderate and severe arsenism group, which were obviously higher than the rates in the control group (1.11% (1/90), χ2 values were 8.679,23.690, 41. 199,respectively,both P values ＜ 0. 017 ). The positive rates of methylation of p53 gene were 25.00% (6/24)and 63. 16% (12/19)in non-cancerous and cancerous group respectively, which were obviously higher than those in the control group ( 1. 11% (1/90) ,χ2 values were 18. 762,57. 497,respectively,both P values ＜0. 025 ). The positive rates of methylation of p53 gene ( exon 5 ) were 55.26% ( 21/38 ), 51. 16% ( 22/43 )and 48. 39% (15/31)respectively among mild, moderate and severe arsenism group,which were obviously lower than the rates in the control group ( 88. 88% ( 80/90 ), χ2 values were 18. 151 , 23. 168,22. 420,respectively, both P values ＜ 0. 017 ). The positive rates of methylation of p53 gene (exon 5 ) were 54. 17%(13/24) and 42. 11% (8/19) in non-cancerous and cancerous group respectively, which were obviously lower than those in the control group ( 88. 88% (80/90), χ2 values were 15. 201,22. 075, respectively, both P values ＜ 0. 025 ). The mutation rates of p53 gene ( exon 5 ) were respectively 5. 26% ( 2/38 ), 16. 28%(7/43) and 25.81% (8/31 )among mild, moderate and severe arsenism group; while the results in moderate and severe arsenism group were obviously higher than in the control group (0. 00% ,χ2 values were 15.465,24. 870,respectively,both P values ＜ 0. 017). The positive rate of mutation of p53 gene ( exon 5 ) were respectively 16. 67% (4/24) and 31.58% ( 6/19 ) in non-cancerous and cancerous group, which were obviously higher than it in the control group (0. 00%, χ2 values were 15. 545,30. 077, both P values ＜0. 025). The hypermethylation of p53 gene in promoter region was related with the mutation of p53 gene ( exon 5) ( coefficient of association was 0. 294, P value ＜ 0. 05 ); and the hypomethylation of p53 gene (exon 5 ) was related with the its mutation ( coefficient of association was 0. 410, P value ＜ 0. 05 ).Conclusion Arsenic pollution caused by coal-burning can cause the hypermethylation of p53 gene in promoter region, hypomethylation and mutation of p53 gene ( exon 5 ), and the changes of methylation of p53 gene are related with its mutation and might be one of the important etiological factors of arsenic pathogenicity or carcinogenesis.     

帕金森病Parkin,LRRK 2基因序列变异研究

目的 探讨散发性早发性帕金森病患者遗传易感基因突变的形式和分布及易感基因突变在PD发病中的可能作用.方法 病例组由23例散发性早发帕金森患者组成,10例对照组.以基因组DNA为模板,扩增Parkin基因的第1、4、6号外显子和LRRK 2基因的第31号外显子.观察PCR产物测序后的突变情况.结果 发现样本中存在突变以及单核苷酸多态性(Single Nucleotide Polymorphism,SNP).在一例患者Parkin基因Exon6上发现735ntT→C,对应的密码子TGT212CGT,翻译的氨基酸C212R,国内罕有报道.另一例患者Parkin基因Exon6上发现突变833ntG→C,导致第244密码子同义突变.结论 Parkin基因外显子4、6的突变可能是我国散发性早发PD患者的致病原因之一.     

185例华南地区非小细胞肺癌EGFR基因突变分析

目的探讨华南地区非小细胞肺癌（NSCLC）表皮生长因子受体（EGFR）基因突变特点及与临床特征的关系。方法收集本院185例NSCLC肿瘤组织，分别提取DNA，采用荧光PCR法扩增EGFR基因第18、19、20、21号外显子，对扩增片段进行DNA正反向测序并分析。结果185例NSCLC中，62例（33．5％）EGFR基因突变，其中18、19、20、21外显子突变分别为2例、41例、5例、14例；共见突变类型16种，热点突变类型为19外显子DelL747→P752（P753S）（构成比8．1％）、DelE746→A750（构成比45．1％）和21外显子L858R（构成比22．6％）；其中4例19外显子突变正、反向测序结果不一致。见20外显子2361G→A沉默突变（28．1％）；女性突变率显著高于男性（46．2％vs24．3％，X2=9．670，P=0．002）。不吸烟者突变率高于吸烟者（41．4％vs17．1％，X2=7．380，P=0．007）。腺癌患者突变率高于鳞癌患者（38．3％vs6．3％，X2=6．426，P=0．011）。临床Ⅲ期患者突变率显著低于临床Ⅱ期、Ⅳ期患者（10．8％vs53．8％，X2=8．026，P=0．003；10．8％vs41．3％，X2=9．518，P=0．002）。同时，未发现EGFR基因突变率与年龄相关。结论华南地区NSCLC患者EGFR基因突变以19、21外显子突变为主。突变率以女性、不吸烟、腺癌者较高。     

石蜡包埋的石棉肺癌组织中p53基因突变的分析方法

为了利用石蜡包埋的病理组织来研究石棉肺癌的基因突变情况，选用１０例石蜡包埋的石棉肺癌组织进行ＰＣＲ－ＳＳＣＰ分析，检测其抗癌基因ｐ５３的第５、第７和第８外显子的突变情况。经银染检查，发现４个病例的ｐ５３基因的第７或第８外显子片段呈突变阳性。用放射性自显影的ＰＣＲ－ＳＳ－ＣＰ方法分析这１０例病例，检测到７个病例的ｐ５３基因第７或第８外显子片段呈突变阳性。用两种方法检测均未发现这１０个病例的第５外显子呈突变阳性。银染ＰＣＲ－ＳＳＣＰ检测可检出放射性自显影ＰＣＲ－ＳＳＣＰ分析结果的６０％，二者的结果相符合。因而，简便、灵敏而且危害性小的银染检测方法，可以代替放射性自显影用于ＰＣＲ－ＳＳＣＰ分析，研究石棉肺癌的基因突变情况。     

p16基因结构及表达异常与非小细胞肺癌的关系

目的　探讨p16基因结构及表达异常与非小细胞肺癌临床病理因素的相关性。方法　利用免疫组化、PCR -SSCP方法检测了p16基因的表达水平及第 2外显子突变 ,并将以上结果与 5 2例非小细胞肺癌 (NSCLC)临床病理因素进行相关性研究。结果　p16基因第 2外显子缺失 /突变率为 2 3 1% (12 /5 2 ) ,p16蛋白丢失率为 5 3 8% (2 8/5 2 ) ,基因的缺失和蛋白的丢失与肺癌的转移和分期有关。结论　p16基因突变及表达异常可能在NSCLC的发生、发展中起重要作用 ,检测该基因可作为临床诊断及预后评估指标。     

PCR-SSCP技术检测矽肺合并肺癌癌组织p53基因突变的研究

用ＰＣＲ－ＳＳＣＰ分析法对３６例矽肺患者的石蜡包埋的原发性肺癌组织ｐ５３基因第５、７、８外显子进行了检测，检出突变１５例。突变在第５、７、８外显子上都有发生，但以第８外显子上发现的阳性突变最多。对肿瘤类型和ｐ５３基因突变的关系进行了分析，发现矽肺病例肺腺癌ｐ５３基因阳性突变率最高，为５３．９％，高于普通型肺癌（３３．０％）。进一步对其中１例样本进行核苷酸序列直接测定，结果显示第５外显子非突变热点区的第１４４位密码子核苷酸由ＣＡＧ突变为ＡＡＧ，氨基酸由谷氨酰胺突变为赖氨酸，以上结果与非职业肺癌明显不同，提示ｐ５３基因突变在矽肺病例肺癌发生中起着重要作用，可能与矽尘作业环境中含有的某些化学致癌物有关。     

人宫颈癌及慢性宫颈炎组织内P_(53)基因变异的研究

本文应用多聚酶链反应—单链构象多态性(PCR-SSCP)分析,对人宫颈癌(cervical carcinoma)和慢性宫颈炎(chronic cervicitis)组织内的P_(53)基因5-6、7-8、9外显子(exon)变异进行研究。结果表明:35例宫颈癌组织中8例出现了异常电泳带,总变异率22.86％(8/35)。其中,5-6外显子2例,变异率为5.71％(2/35);7-8外显子5例,变异率为14.29％(5/35),是变异率最高的基因片段;9外显子1例,变异率为2.86％(1/35)。8例变异标本中3例P_(53)5-6、7-8外显子同时发生突变,占变异标本的37.5％(3/8),占宫颈癌组织总标本的8.57％(3/35)。17例慢性宫颈炎组织P_(53)5-6、7-8、9外显子均未出现异常。提示:PCR-SSCP技术能有效地检出宫颈组织P_(53)基因5-9外显子变异的情况;P_(53)5-9变异是人宫颈癌发生发展过程中的一个重要事件和生物学行为;宫颈癌组织P_(53)变异多发生在5-8外显子,有不同外显子同时变异的现象;慢性宫颈炎组织无P_(53)5-6、7-8、9外显子变异现象,说明该病的发生发展与抑癌基因P_(53)外显子变异无关。     

四川省部分地区43例高苯丙氨酸血症患儿相关基因突变分析

目的 了解四川省部分地区高苯丙氨酸血症(HPA)患儿基因突变情况,构建本地区HPA相关基因突变谱,为患儿基因诊断、产前诊断及遗传咨询提供依据。方法 采用第二代测序技术对43例HPA患儿的PAH、PTS、QDPR、PCBD1、SPR及GCH1基因进行分析。结果 检出PAH基因突变35例,PTS基因突变8例。占前3位的PAH高频突变为p.R243Q、p.R241C及p.Ex6-96A>G,高频突变的区域为第7外显子,包含了28个突变(39.4%)。p.G272V未见报道。PTS基因的高频突变位点为p.P87S、p.Y27Rfs*8、p.D96N及p.V56M,高频突变区域为第5外显子,包含了8个突变(50.0%)。p.T58R未见报道。结论 本研究初步构建了四川省部分地区HPA相关基因的突变谱,在PAH和PTS基因上各发现1个新突变,为本地区HPA患儿的基因诊断和遗传咨询提供了依据。     

四川省部分地区43例高苯丙氨酸血症患儿相关基因突变分析

目的 了解四川省部分地区高苯丙氨酸血症(HPA)患儿基因突变情况,构建本地区HPA相关基因突变谱,为患儿基因诊断、产前诊断及遗传咨询提供依据。方法 采用第二代测序技术对43例HPA患儿的PAH、PTS、QDPR、PCBD1、SPR及GCH1基因进行分析。结果 检出PAH基因突变35例,PTS基因突变8例。占前3位的PAH高频突变为p.R243Q、p.R241C及p.Ex6-96A>G,高频突变的区域为第7外显子,包含了28个突变(39.4%)。p.G272V未见报道。PTS基因的高频突变位点为p.P87S、p.Y27Rfs*8、p.D96N及p.V56M,高频突变区域为第5外显子,包含了8个突变(50.0%)。p.T58R未见报道。结论 本研究初步构建了四川省部分地区HPA相关基因的突变谱,在PAH和PTS基因上各发现1个新突变,为本地区HPA患儿的基因诊断和遗传咨询提供了依据。     

AGT基因M235T变异与腰臀比异常对原发性高血压的影响

目的探讨AGT基因第二外显子编码M235T变异与腰臀比异常及其交互作用对原发性高血压的影响。方法对从青岛市4个社区中筛检出的、未经药物系统治疗的235例原发性高血压病人及240例正常血压者进行调查,用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法检测M235T变异;应用相加模型分析M235T变异与腰臀比异常的交互作用。结果高血压组T等位基因频率(46.81%)及腰臀比异常率(69.79%)高于对照组(分别为37.71%,47.92%),差别有统计学意义(χ2=8.677,23.433,P0.01)。AGT基因M235变异与腰臀比异常具有正交互作用。用多因素分析调整年龄、性别、体质指数、饮酒、吸烟、血脂等因素后,M235T基因变异与腰臀比异常的协同效应指数(S)为1.945,归因交互效应(AB)为1.022,归因交互效应百分比(AP%)为32.91%,纯因子间AP为48.55%。结论 AGT基因第二外显子编码M235T变异与原发性高血压有关,AGT基因M235T变异与腰臀比异常具有正交互作用,控制腰臀比异常可以降低居民原发性高血压患病的危险性。     

AIS大家系的AR突变效应分析

目的：分析雄性激素不敏感综合征（AIS）大家系的AR突变效应。方法：从AIS患者外周血中将基因组DNA提取出来,以特异的引物聚合酶联反应（PCR）扩张雄激素受体（AR）基因,单链构象多态性分析（SSCP）扩增产物,将突变的外显子筛选出来,然后对其直接进行PCR产物测序。结果：所选取的8例人员中,有2例AIS患者缺失AR基因2号外显子,其余6例存在外显子电泳条带,经过基因测序,发现其符合正常AR基因。结论：本研究方法简便实用,在临床诊断和研究AIS中具有极为有益的应用。     

Comparative study on Tp53 gene mutations in lung tumors from rats exposed to 239Pu, 237Np and 222Rn

The tumor suppressor gene Tp53 was analyzed by polymerase chain reaction-amplification of genomic DNA extracted from paraffin-embedded tissue sections of rat lung tumors to compare mutations that occurred after inhalation exposures to plutonium dioxide, neptunium dioxide, or radon and radon progenies. Exons 5 to 8 of the gene were amplified in 16 plutonium-, 23 neptunium- and 15 radon-induced lung tumors, and their polymerase chain reaction products were examined for mutations by single strand conformational polymorphism analysis and direct sequencing method. Two point mutations were detected in the plutonium-induced tumors, i.e., a guanine to adenine transition at codon 219 of exon 6 and a cytosine to thymine transition at codon 266 of exon 8. Although only one point mutation was found at codon 175 of exon 5 (cytosine to thymine transition) from neptunium-induced tumors, no mutations were detectable from radon-induced tumors. These results indicate that the abnormalities of the Tp53 gene might not be so critical for the pulmonary carcinogenesis after the inhalation of different alpha emitters, even though the presence and frequencies of the Tp53 gene mutations were different.     

聚合酶链反应-单链构象多态法在研究新疆地方性砷中毒患者p53基因突变中的应用

目的 探索砷致癌的基因多态性,为进一步研究砷对人体健康作用的远期影响提供科学依据.方法 于2001年采集新疆奎屯123团4例经病理诊断为皮肤癌的砷中毒患者的6份皮肤癌石蜡包埋组织及其4份血液组织;采集奎屯128团2例经病理诊断为皮肤癌的砷中毒患者和2例癌前砷中毒患者的血液组织;采集对照区新疆奎屯125团2例健康居民的血液组织.采用聚合酶链反应-单链构象多态(PCR-SSCP)银染术测定p53基因外显子(exon,E)5～9突变情况.结果 p53基因中,仅E6、E7发生突变.凝胶电泳成像显示,p53基因E6、E7有异常条带、条带缺失及条带上移现象.结论 砷对p53基因有致突变作用,突变位于E6、E7.