乙肝病毒/黄曲霉毒素B1双暴露相关性肝细胞癌的p53基因249位点突变与p53蛋白表达的关系

目的研究乙肝病毒/黄曲霉毒素B1双暴露相关性肝细胞癌的p53基因249位点突变与p53蛋白表达关系。方法通过IHG特殊免疫组织化学法检测55例手术切除经病理证实为原发性肝癌的HCC组织及10例正常肝组织中AFB1-DNA加合物的暴露情况,并根据是否同时存在HBV暴露加以分组,通过免疫组化S-P法检测并比较各组间p53蛋白的表达情况。同时,通过PCR结合直接测序的方法检测其p53基因第7外显子249密码子的突变情况。结果 p53基因第7外显子249位点的突变在实验组A与对照组C中均具有较高阳性突变率,其突变率分别为68.75%（22/32）、63.64%（7/11）,在对照组B中的突变率较低,为16.67%（2/12）,在正常对照组中无1例出现有突变。其中实验组A与对照组B及正常对照组D的比较差异具有统计学意义（P〈0.05）,而与对照组C比较差异无统计学意义（P〉0.05）;p53蛋白在其基因249位点突变阳性组与阴性组中的表达阳性率分别为92.86%（26/28）、60.87%（16/27）,差异具有统计学意义（P〈0.05）。结论 HCC的发生过程中,AFB1暴露与p53第7外显子249位点的突变密切关系相关,当同时存在乙肝病毒暴露的协同作用的情况下突变率更高;p53基因的突变可能是造成HCC中p53蛋白高表达的重要因素之一。     

乙肝病毒/黄曲霉毒素B1双暴露相关性肝细胞癌的p53基因249位点突变与p53蛋白表达的关系

目的研究乙肝病毒/黄曲霉毒素B1双暴露相关性肝细胞癌的p53基因249位点突变与p53蛋白表达关系。方法通过IHG特殊免疫组织化学法检测55例手术切除经病理证实为原发性肝癌的HCC组织及10例正常肝组织中AFB1-DNA加合物的暴露情况,并根据是否同时存在HBV暴露加以分组,通过免疫组化S-P法检测并比较各组间p53蛋白的表达情况。同时,通过PCR结合直接测序的方法检测其p53基因第7外显子249密码子的突变情况。结果 p53基因第7外显子249位点的突变在实验组A与对照组C中均具有较高阳性突变率,其突变率分别为68.75%(22/32)、63.64%(7/11),在对照组B中的突变率较低,为16.67%(2/12),在正常对照组中无1例出现有突变。其中实验组A与对照组B及正常对照组D的比较差异具有统计学意义(P<0.05),而与对照组C比较差异无统计学意义(P>0.05);p53蛋白在其基因249位点突变阳性组与阴性组中的表达阳性率分别为92.86%(26/28)、60.87%(16/27),差异具有统计学意义(P<0.05)。结论 HCC的发生过程中,AFB1暴露与p53第7外显子249位点的突变密切关系相关,当同时存在乙肝病毒暴露的协同作用的情况下突变率更高;p53基因的突变可能是造成HCC中p53蛋白高表达的重要因素之一。     

广西原发性肝细胞癌黄曲霉毒素B1-DNA加合物表达及p53第249密码子突变分析

目的 通过研究广西地区肝癌患者中黄曲霉毒素B1(Aflatoxin B1,AFB1)-DNA加合物的表达和p53第249密码子突变情况及其关系,探讨AFB1长期暴露与人群原发性肝细胞癌(hepatocellular carcinoma,HCC)发生的关系.方法 实验组为广西医科大学第一附属医院肝胆外科收治的63例HCC患者行根治性手术切除的肝肿瘤组织.按肿瘤大小分为小肝癌组(≤5cm)和大肝癌组(＞5cm),同时小肝癌组包括两个亚组Ⅰ组(≤3cm)和Ⅱ组(＞3cm).另取10例来自肝移植供肝及肝外伤切除的正常肝组织作为正常对照组.通过免疫组织化学(immunohistochemistry,IHC)法检测各组样本AFB1-DNA加合物的表达,并以PCR结合直接测序的方法 检测其p53第249密码子的突变情况.结果 小肝癌组的AFB1-DNA加合物阳性率最高(73.8%),显著高于大肝癌组(P=0.016).而小肝癌组p53第249密码子的突变率(35.7%)却显著低于大肝癌组(P=0.007).正常对照组AFB1-DNA加合物阳性率为50.0%,但未发现p53第249密码子存在突变.Ⅰ组与Ⅱ组之间无论是AFB1-DNA加合物阳性率还是p53第249密码子的突变率差异均无统计学意义(P1=0.676,P2=1.000).实验组中,33.3%的样本为AFB1-DNA加合物和p53第249密码子突变双阳性,22.2%的样本为AFB1-DNA加合物和第249密码子突变双阴性.结论 广西为AFB1高污染地区,正常人群普遍存在AFB1的暴露.AFB1的暴露可增加HCC的发病概率.p53第249密码子突变可能是影响AFB1相关HCC发生、发展的因素.结合AFB1-DNA加合物表达和第249密码子突变的情况,可有效地了解肝癌患者长期持续性或非持续性的AFB1暴露下DNA的累积损伤情况.     

广西原发性肝细胞癌黄曲霉毒素B_1-DNA加合物表达及p53第249密码子突变分析

目的通过研究广西地区肝癌患者中黄曲霉毒素B1（Aflatoxin B1,AFB1）-DNA加合物的表达和p53第249密码子突变情况及其关系,探讨AFB1长期暴露与人群原发性肝细胞癌（hepatocellular carcinoma,HCC）发生的关系。方法实验组为广西医科大学第一附属医院肝胆外科收治的63例HCC患者行根治性手术切除的肝肿瘤组织。按肿瘤大小分为小肝癌组（≤5cm）和大肝癌组（〉5cm）,同时小肝癌组包括两个亚组Ⅰ组（≤3cm）和Ⅱ组（〉3cm）。另取10例来自肝移植供肝及肝外伤切除的正常肝组织作为正常对照组。通过免疫组织化学（immunohistochemistry,IHC）法检测各组样本AFB1-DNA加合物的表达,并以PCR结合直接测序的方法检测其p53第249密码子的突变情况。结果小肝癌组的AFB1-DNA加合物阳性率最高（73.8%）,显著高于大肝癌组（P=0.016）。而小肝癌组p53第249密码子的突变率（35.7%）却显著低于大肝癌组（P=0.007）。正常对照组AFB1-DNA加合物阳性率为50.0%,但未发现p53第249密码子存在突变。Ⅰ组与Ⅱ组之间无论是AFB1-DNA加合物阳性率还是p53第249密码子的突变率差异均无统计学意义（P1=0.676,P2=1.000）。实验组中,33.3%的样本为AFB1-DNA加合物和p53第249密码子突变双阳性,22.2%的样本为AFB1-DNA加合物和第249密码子突变双阴性。结论广西为AFB1高污染地区,正常人群普遍存在AFB1的暴露。AFB1的暴露可增加HCC的发病概率。p53第249密码子突变可能是影响AFB1相关HCC发生、发展的因素。结合AFB1-DNA加合物表达和第249密码子突变的情况,可有效地了解肝癌患者长期持续性或非持续性的AFB1暴露下DNA的累积损伤情况。     

乙型肝炎病毒及黄曲霉毒素双暴露下肝细胞癌中p53基因突变及蛋白表达的意义

目的探讨在乙型肝炎病毒(hepatitis B virus,HBV)和黄曲霉毒素B1(aflatoxin B1,AFB1)双暴露下肝细胞癌(hepatocelluar carcinoma,HCC)中p53基因突变及其蛋白的表达,并分析其意义。方法根据HBV与AFB_1的暴露情况,将广西地区HCC 82例患者分为HBV(+)/AFB_1(+)(实验组A组)44例;HBV(+)/AFB1(-)(对照组B组)15例;HBV(-)/AFB_1(+)(对照组C组)15例;HBV(-)/AFB_1(-)(对照组D组)8例,另收集肝外伤、肝血管瘤等20例肝切除组织作为正常对照组。用PCR技术及免疫组化法对p53基因11对外显子的突变及蛋白的表达进行检测。结果 82例HCC患者p53exon7-249阳性突变率为40.2%,正常对照组的阳性突变率为0,实验组A组、对照组B组、对照组C组和对照组D组的阳性突变率分别为50.0%、13.3%、46.7%和25.0%,其中实验组A组比对照组B组有更高的突变率(P<0.05),其余各组比较差异均无统计学意义(P>0.05)。82例HCC患者中p53蛋白的阳性表达率为74.4%,正常对照组p53蛋白表达的阳性率为0,实验组A组、对照组B组、对照组C组和对照组D组的阳性表达率分别为90.9%、46.7%、73.3%和37.5%,其中实验组A组分别比对照组B组、对照组D组有更高的阳性表达率(P<0.05),其余各组比较差异均无统计学意义(P>0.05)。p53exon7-249突变与p53蛋白的表达呈正相关(P<0.05)。结论在广西地区HBV和AFB1双暴露因素下的HCC发生过程中,p53基因有更高的突变率及蛋白表达,尤以p53exon7-249突变为其特征性改变,为该地区HCC发生常见的一种分子生物学事件;p53基因的高突变率及其蛋白高表达率可能为HBV和AFB1协同作用的结果。     

广西乙肝病毒/黄曲霉毒素B1双暴露人肝细胞癌中PTEN mRNA表达及突变的初步研究

目的探讨乙肝病毒/黄曲霉毒素B1双暴露相关肝细胞性肝癌(HCC)中PTEN基因的突变特点及其mRNA的表达水平。方法 108例HCC来自广西不同地区样本,按照乙肝病毒与黄曲霉毒素的暴露情况,分为4个亚组:A组:HBV(+)/AFB1-DNA(+),共48例;B组:HBV(+)/AFB1-DNA(-),共27例;C组:HBV(-)/AFB1-DNA(+),共19例;D组:HBV(-)/AFB1-DNA(-),共14例。采用PCR联合基因直接测序法,检测108例肝癌组织中PTEN基因第4、5、8外显子的突变情况。同时采用RT-PCR法检测其基因mRNA的表达状况。结果①PTEN基因第4、5、8外显子测序结果未发现发生在外显子上的突变。但在第4外显子与第4内含子交界处有61例发生大片段的缺失,缺失率为56.4%。②PTEN缺失率在A、B、C、D组中分别为60.4%、62.9%、47.3%和46.6%,其差异在4个亚组间均无统计学意义(P>0.05)。③PTEN mRNA在4个亚组中的表达半定量灰度值分别为:A组:0.54±0.13;B组:0.59±0.16;C组:0.97±0.16;D组:0.92±0.13。其中,A、B组分别与C、D组相比,其差异均具有统计学意义(PAC=0.002,PAD=0.032,PBC=0.000,PBD=0.011)。结论在广西乙型肝炎病毒/黄曲霉毒素B1的双暴露肝细胞癌中,PTEN mRNA的表达下调是一个常见的分子生物学事件,PTEN mRNA表达下调可能主要与HBV感染有关。AFB1对PTEN mRNA的表达下调可能有协同作用。     

广西乙肝病毒／黄曲霉毒素B1双暴露人肝细胞癌中PTENmRNA表达及突变的初步研究

目的探讨乙肝病毒／黄曲霉毒素B1双暴露相关肝细胞性肝癌（HCC）中PTEN基因的突变特点及其mRNA的表达水平。方法108例HCC来自广西不同地区样本,按照乙肝病毒与黄曲霉毒素的暴露情况,分为4个亚组：A组：HBV（＋）／AFB1-DNA（＋）,共48例;B组：HBV（＋）／AFB1-DNA（-）,共27例;C组：HBV（-）／AFB1-DNA（＋）,共19例;D组：HBV（-）／AFB1-DNA（-）,共14例。采用PCR联合基因直接测序法,检测108例肝癌组织中PTEN基因第4、5、8外显子的突变情况。同时采用RT—PCR法检测其基因mRNA的表达状况。结果（1）PTEN基因第4、5、8外显子测序结果未发现发生在外显子上的突变。但在第4外显子与第4内含子交界处有61例发生大片段的缺失,缺失率为56.4％。②PTEN缺失率在A、B、C、D组中分别为60．4％、62．9％、47．3％和46．6％,其差异在4个亚组间均无统计学意义（P〉0．05）。@PTENmRNA在4个亚组中的表达半定量灰度值分别为：A组：0．54±0．13;B组：0．59±0．16;C组：0．97±0．16;D组：0．92±0．13。其中,A、B组分别与C、D组相比,其差异均具有统计学意义（PAC=0．002,PAD=0．032,PBC=0．000,PBC=0．011）。结论在广西乙型肝炎病毒／黄曲霉毒素B1的双暴露肝细胞癌中,PTENmRNA的表达下调是一个常见的分子生物学事件,PTENmRNA表达下调可能主要与HBV感染有关。AFB1对PTENmRNA的表达下调可能有协同作用。     

肝癌非高发区安徽省肝细胞癌p53基249密码子点突变的研究

目的： 研究 p53基因 249密码子在肝癌非高发区安徽省的点突变的发生率。方法：应用 PCR- RFLP技术分析肝细胞癌 p53基因 249密码子突变的频率。结果：所检测的 38例肝细胞癌均无出现 p53基因第七外显子纯合性缺失, 4例有 p53基因 249密码子的点突变,且均为杂合型突变,突变率为 10.53％ (4/38)。结论：本资料说明,在肝细胞癌非高发区中 ,肝细胞癌中 p53基因第七外显子发生的点突变并非为高发事件。提示 p53基因第七外显子的点突变在肝癌非高发区肝细胞癌的形成过程中可能不起主导作用。     

肝硬化及肝癌p53基因突变的实验研究

目的 :研究肝硬化及肝癌p53基因的突变情况。方法 :选择 80例肝硬化、肝癌标本 ,分别以PCR SSCP法 ,双链DNA序列测定法研究其p53基因外显子的突变情况及突变位点。结果 :62例肝癌标本p53总突变率为 19 4 % ,其中 ,早、中、晚期突变率分别为 10 5%、15 0 %、35 0 % ;18例肝硬化标本p53总突变率为 5 6% ;第 7外显子的突变发生在 2 4 9位密码子第 3号碱基上 ,为G :C→T :A的颠换突变 ;第 8外显子的突变发生在 2 73位密码子第 1号碱基上 ,为C :G→T :A的转换突变。结论 :p53基因突变发生在肝细胞发生形态学改变之初 ,随着肝癌的进展逐渐积累 ,突变率呈上升趋势 ,故p53基因突变很可能是启动癌变过程的重要因素之一。     

肝细胞癌组织中β-Catenin的表达与第三外显子突变的关系

背景与目的:广西南部是肝细胞癌(hepatocellular carcinoma,HCC)高发地区,也是粮食受黄曲霉毒素B1(aflatoxin B1,AFB1)污染较重的地区.β-Catenin 的异常表达与多种肿瘤有关.而AFB1是诱发HCC的重要因素.本研究旨在探讨AFB1高暴露地区HCC患者癌组织中β-Catenin基因突变及表达情况.方法:用基因直接测序、RT-PCR、免疫组化和Western blot等方法,检测52例来自广西南部AFB高暴露地区HCC患者癌、癌旁组织和18例非肝癌肝组织中β-Catenin基因的表达.结果:癌组织中未见β-Catenin基因第三外显子的突变.β-Catenin mRNA 在癌、癌旁和正常肝组织中的表达分别为0.42±0.24、0.20±0.16和0.23±0.12,癌组织中的表达显著高于癌旁组织或正常肝组织(P＜0.01);免疫组化染色癌组织中阳性率为55.8%(29/52),显著高于癌旁组织[36.5%(19/52)](P＜0.05).β-Catenin蛋白表达与肝外转移、术后复发、门静脉癌栓和临床分期有关(P＜0.05),而mRNA的表达与上述临床参数均无明显关系(P＞0.05).结论:β-Catenin在HCC组织中高表达,但其异常表达不是由基因第三外显子上GSK-3β磷酸化位点的突变引起.     

A MOLECULAR EPIDEMIOLOGIC MARKER OF HEPATOCELLULAR CARCINOMA FROM AFLATOXIN B1 CONTAMINATED AREA IN THE SOUTHWEST OF GUANGXI

ＡＭＯＬＥＣＵＬＡＲＥＰＩＤＥＭＩＯＬＯＧＩＣＭＡＲＫＥＲＯＦＨＥＰＡＴＯＣＥＬＬＵＬＡＲＣＡＲＣＩＮＯＭＡＦＲＯＭＡＦＬＡＴＯＸＩＮＢ１ＣＯＮＴＡＭＩＮＡＴＥＤＡＲＥＡＩＮＴＨＥＳＯＵＴＨＷＥＳＴＯＦＧＵＡＮＧＸＩＤｅｎｇＺｈｕｏｌｉｎ邓卓霖ＭａＹ...     

The chemistry and biology of aflatoxin B(1): from mutational spectrometry to carcinogenesis

Dietary exposure to aflatoxin B(1) (AFB(1)) is associated with an increased incidence of hepatocellular carcinoma (HCC), especially in populations in which exposure to hepatitis B virus (HBV) is a common occurrence. Most HCC samples from people living where HBV is prevalent have one striking mutational hotspot: a GC-->TA transversion at the third position of codon 249 of the p53 gene. In this review, the chemical reaction of an electrophilic derivative of aflatoxin with specific DNA sequences is examined, along with the types of mutations caused by AFB(1) and the sequence context dependence of those mutations. An attempt is made to assign the source of these mutations to specific chemical forms of AFB(1)-DNA damage. In addition, epidemiological and experimental data are examined regarding the synergistic effects of AFB(1) and HBV on HCC formation and the predominance of one hotspot GC-->TA transversion in the p53 gene of affected individuals.     

中国高发区肝细胞癌p53基因热点突变的规律性

目的 研究同发区肝细胞癌（ＨＣＣ）Ｐ５３基因２４９密码子高频度突变的规律性,为探寻癌及基于Ｐ５３的基因和免疫治疗提供依据。方法 用巢工ＰＣＲ结合测序和限制性片段长度多态（ＲＦＬＰ）分析的方法,研究１９９４－１９９７年收集的９７例启东和２２便北京的肝细胞癌标本中,Ｐ５３基因２４９密码子的突变率及突变的基因型。用免疫组化法研究癌及癌周细胞中Ｐ５３蛋白的表达程度。 １９９４－１９９７年,启东肝细胞癌中,     

Hepatitis B virus infection contributes to oxidative stress in a population exposed to aflatoxin B1 and high-risk for hepatocellular carcinoma

Biomarkers of hepatitis B virus (HBV) infection, aflatoxin B1 (AFB1) exposure and oxidative stress were detected in 71 hepatocellular carcinoma (HCC) patients and 694 controls from southern China. Plasma level of AFB1-albumin-adducts (AAA) and protein carbonyl content (PCC) were significantly higher in the 71 HCC cases than in any age/gender matched HBV sero-status groups (p<0.001). HCC patients positive for the p53-249 G-T mutation had a marginally higher level of PCC than those negative for the mutation (p=0.077). HBV infection had a prominent influence on the association between AFB1 exposure and oxidative stress biomarkers in the controls. Our study indicates a significant contribution from HBV infection to oxidative stress in a population with AFB1 exposure which might substantially increase risk for HCC in this region.     

Different frequencies of p53 codon-249 hot-spot mutations in hepatocellular carcinomas in Jiang-su province of China.

Environmental carcinogens often induce specific mutations in the p53 gene, apparent in tumors. The relation between aflatoxin B1 (AFB1 )-related hepatocellular carcinomas (HCCs) and hot spot at codon 249 of the p53 gene has received a great deal of attention, but its significance is still controversial. To clarify this problem, we analyzed the p53-mutational status of HCCs in Jiang-su province in China, where AFB1 contamination of the staple food significantly differs between the northern and southern parts (prominent only in the latter), while other conditions are quite similar. Background liver status and mutations in exons 5 to 8 of p53 in a total of 31 cases were divided approximately equally between the 2 areas. In all, 15 tumors exhibited a total of 17 mutations in the p53 gene; 9 cases from the southern part of the province had the hot-spot mutation at codon 249 (9/16, 56%), but only one case from the northern part (1/15, 8%). These results suggest that AFB1 contamination may correlate with codon-249 mutations in HCC.     

Aberrations of p53 gene in human hepatocellular carcinoma from China

Allele losses and mutations have been examined in 38 cases ofprimary hepatocellular carcinomas (HCC) from different geographicareas of China by Southern, single-strand conformational polymorphism(SSCP) and direct DNA sequencing analyses. Two of 12 samplesfrom Qi-Dong and six of 18 HCCs from Shanghai showed loss ofheterozygosity (LOH) at the loci on chromosome 17p13.3. Allof the nine mutations in the p53 gene detected in HCC from Qi-Dongwere clustered at the third base of codon 249, i.e. G:C to T:A,leading to an arginine to serine change. In contrast, 18 HCCsamples from Shanghai contained three mutations at codons 249,255 and 279. These results suggested a relationship betweenthe spectrum of p53 aberration and environmental risk factorsin these two geographic areas. Since no correlation betweenthe state of HBV DNA and p53 abberration was observed, otherfactors such as dietary exposure to aflatoxin B1 (AFB1) mightbe responsible for the mutational hotspot at codon 249 in HCCsfrom Qi-Dong area.     

Hepatitis B Virus Genetic Variation and TP53 R249S Mutation in Patients with Hepatocellular Carcinoma in Thailand

Chronic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin B1 (AFB1) are major risk factorsfor hepatocellular carcinoma (HCC). The aim of this study was to evaluate the role of HBV genetic variationand the R249S mutation of the p53 gene, a marker of AFB1-induced HCC, in Thai patients chronically infectedwith HBV. Sixty-five patients with and 89 patients without HCC were included. Viral mutations and R249Smutation were characterized by direct sequencing and restriction fragment length polymorphism (RFLP)in serum samples, respectively. The prevalences of T1753C/A/G and A1762T/G1764A mutations in the basalcore promotor (BCP) region were significantly higher in the HCC group compared to the non-HCC group.R249S mutation was detected in 6.2% and 3.4% of the HCC and non-HCC groups, respectively, which was notsignificantly different. By multiple logistic regression analysis, the presence of A1762T/G1764A mutations wasindependently associated with the risk of HCC in Thai patients.     

The role of previous infection of hepatitis B virus in Hbs antigen negative and anti-HCV negative Japanese patients with hepatocellular carcinoma: etiological and molecular biological study

The aim of this study is to elucidate the important role of the previous infection of HBV, and the relations among HBV genome integration and p53 gene mutation, telomerase activity and genetic instability in liver tissue with HBsAg-negative (NB) and anti-HCV negative (NC) hepatocellular carcinoma (HCC). We examined the backgrounds of 34 NB and NC (NBNC) Japanese patients with chronic liver disease (CLD) patients not associated with HCC and 26 NBNC CLD patients with HCC. HBV genome integration into host cell genome, p53 gene mutation telomerase activity and genetic instability were examined in 6 with NBNC HCC (NBNC-HCC) tumorous tissue (T) and non-tumorous tissues (NT). In the NBNC group, HBV-related antibody positive patients with HCC are significantly more than the patients without HCC. Moreover, concerning the stage of the coexisted liver diseases, in NBNC CLD, LC patients with HCC is 19 of 26 (73.1%) , on the other hand, LC patients without HCC is 16 of 34 (47.1%). LC patients with HCC group is significantly more than that without HCC. Three (50%) of 6 in T and 3 cases (50% ) in NT were found to integrated genome of HBV. p53 gene mutation was observed in 3 (50%) of T. Concerning the telomerase activity, 3 of 6 cases (50%) in T and 1 case in NT was recognized. There was no genetic instability (LOH or RER) of D2S123, D3S1067 and TP 53 in T and NT. Finally in T of NBNC HCC cases, TTVDNA was detected in 3 of 5. Even in the HBsAg-negative and anti-HCV negative HCC cases, CLD coexisting with LC, previous HBV infection and HBVDNA integration were observed. There were a few cases with HBVDNA integration, p53 gene mutation, telomerase activity and genetic instability, simultaneously in HCC tissue, and in some cases, the coexistence with TTVDNA were concurrently confirmed. It is speculated that the important role of the previous infection of HBV may have also been proposed for HCC oncogentic progression in NBNC CLD [corrected].