三种危险因素的协同致肿癌作用

为分析黄曲霉毒素，乙型肝炎病毒和丙型肝炎病毒在致人原发性肝细胞癌时可能的协同作用，对同份人ＨＣＣ组织分别采用高效液相色谱法，嵌套式ＰＣＲ及逆转录嵌套式ＰＣＲ检测，ＡＦＢ１，ＨＢＶ，ＤＮＡ和ＨＣＶ ＲＮＡ，检出率分别为６７．７％，８８．２％，和１３．２％。其中，ＡＦＢ１和ＨＢＶ ＤＮＡ重叠检出率为５８．１％，ＨＢＶ ＤＮＡ和ＨＣＶＲＮＡ重叠检出率为８．８％，由４例ＨＣＣ患者重叠检出ＡＦＢ１，ＨＢＶ、     

广西85例肝癌患者庚型肝炎病毒感染的血清学研究

对肝癌高发区的８５例患者血清采用套式ＰＣＲ方法检测认型肝炎病毒核糖核酸（ＨＧＶ－ＲＮＡ），并用相同方法检测了ＨＣＶ－ＲＮＡ；ＨＢＶ－ＤＮＡ则采用单次ＰＣＲ检测，阴性者再用套式ＰＣＲ证实。结果提示：８５例肝癌患者中，１１例患者可检出ＨＧＶＲＮＡ，占和的１２．９％，而ＨＣＶ－ＲＮＡ，ＨＢＶ－ＤＮＡ阳性者分别为１５例及６８例，占１７．６％和８０％。初步证明文本部分肝癌病人血清中存在ＧＶ感染，作者认为：Ｈ     

慢性丙型肝炎患者外周血单核细胞中丙型肝炎病毒RNA正,负链的…

选择ＨＣＶ基因组５＇非编码区的两对引物，利用逆转录巢式ＰＣＲ技术对３５例慢性丙型肝炎患的血清中正链ＨＣＶ ＲＮＡ、ＰＢＭＣ中正、负莲ＨＣＶ ＲＮＡ进行检测。结果血清中正链ＨＣＶ ＲＮＡ阳性率为６２．９％（２２／３５），ＰＢＭＣ中正链ＨＣＶ ＲＮＡ的阳性率为５４．３％（１９／３５），负链ＨＣＶ ＲＮＡ的阳性率为３４．３％（１２／３５）。同时对第２次ＰＣＲ的阳性产物进行限制性片段长度多态性分析（ＲＦ     

用RT—PCR法分析合肥地区HCV基因型

应用逆转录－ＤＮＡ聚合酶链反应（ＲＴ－ＰＣＲ），对合肥地区的１９５例病人的血清进行了ＨＣＶＲＮＡ检测及基因型分析。结果显示，８０例ＨＣＶＲＮＡ阳性标本中，７０例（８７．５％）为Ⅱ／１ｂ型ＨＣＶ感染，７例（８．８％）为Ⅲ／２ａ型，３例（３．７％）为Ⅱ和Ⅲ型混合感染，未发现Ⅰ／１ａ和Ⅳ／２ｂ型ＨＣＶ感染。     

肝细胞肿瘤患者癌组织中HBx基因的检测

目的通过检测肝细胞肿瘤（ＨＣＣ）患者癌组织中ＨＢｘ基因探讨乙型肝炎病毒（ＨＢＶ）在 ＨＣＣ中的重要性。方法根据ＨＢｘ基因ＤＮＡ序列设计引物,采用特异性聚合酶链式反应（ＰＣＲ） 对３１例病理确诊并经手术切除后的ＨＣＣ患者癌组织进行了检测,同时采用ＰＣＲ方法检测了同一 患者血清ＨＢＶ ＤＮＡ。结果ＰＣＲ显示３１例ＨＣＣ患者癌组织中ＨＢｘ基因和血清中ＨＢＶ ＤＮＡ 的阳性率分别为７７．４％（２４／３１）和３２．３％（１０／３１）。结论ＨＢｘ基因片段广泛存在于ＨＣＣ患者癌 组织中并且在癌细胞中可能存在整合。     

慢性丙型肝炎患者外周血单核细胞中丙型肝炎病毒RNA正、负链的检测

选择ＨＣＶ基因组５’非编码区的两对引物，利用逆转录巢式ＰＣＲ技术对３５例慢性丙型肝炎患者的血清中正链ＨＣＶＲＮＡ、ＰＢＭＣ中正、负链ＨＣＶＲＮＡ进行检测。结果血清中正链ＨＣＶＲＮＡ阳性率为６２．９％（２２／３５），ＰＢＭＣ中正链ＨＣＶＲＮＡ的阳性率为５４．３％（１９／３５），负链ＨＣＶＲＮＡ的阳性率为３４．３％（１２／３５）。同时对第２次ＰＣＲ的阳性产物进行限制性片段长度多态性分析（ＲＦＬＰ），进一步证实ＰＣＲ产物为ＨＣＶ特异性扩增产物，结果说明ＨＣＶ能在ＰＢＭＣ中存在或复制，即肝细胞并非ＨＣＶ感染与复制的唯一场所。ＰＢＭＣ可能作为病毒长期滞留场所，使病毒感染持续存在，是丙型肝炎易发生慢性化的原因之一。     

加热与洗涤法对HBV,HCV血清标志的影响

采用ＥＬＩＳＡ和聚合酶链反应（ＰＣＲ），对经６０℃１０ｈ加热的ＨＢｓＡｇ、ＨＢｅＡｇ、抗－ＨＢＣ及抗－ＨＣＶ阳性血清和洗涤４次的ＲＢＣ洗涤及放散液的血清标志及ＨＢＶＤＮＡ、ＨＣＶＲＮＡ进行了检测。结果，６０℃加热１０ｈ用ＥＬＩＳＡ检测血清标志均由强阳性转为阳性，ＰＣＲ检测ＨＢＶＤＮＡ及ＨＣＶＲＮＡ均为阴性；洗涤液用ＥＬＩＳＡ和ＰＣＲ检测血清标志及ＨＢＶＤＮＡ、ＨＣＶＲＮＡ均呈阴性反应，放散液用ＥＬＩＳＡ检测阴性，用ＰＣＲ检测ＨＣＶＲＮＡ１０份标本９份阴性，１份阳性。提示６０℃加热１０ｈ和洗涤ＲＢＣ可灭活或去除血清中大部分ＨＢＶ、ＨＣＶ及其血清标志。     

乙型和庚型肝炎病毒感染与肝细胞癌血清流行病学研究

为探讨乙型和庚型肝炎病毒（ＨＢＶ和ＨＧＶ）感染与肝细胞癌（ＨＣＣ）发生的关系，采用酶联免疫吸附法（ＥＬＩＳＡ）和聚合酶链反应（ＰＣＲ）对８５例ＨＣＣ患者血清进行了ＨＢＶ和ＨＧＶ血清标志和ＨＧＶＲＮＡ检测，结果ＨＣＣ患者中ＨＢＶ感染率为７７．６５％；ＨＧＶ感染率为２７．０６％，ＨＧＶ和ＨＢＶ重叠感染率（２２．３５％）明显高于ＨＧＶ单独感染率（４．７１％）。结果提示：ＨＢＶ感染为ＨＣＣ发生的重要原因；ＨＧＶ感染可能参与ＨＣＣ的发生；而ＨＧＶ和ＨＢＶ重叠感染是否有可能增加ＨＣＣ的发生，值得进一步探讨     

聚合酶链反应检测庚型肝炎病毒的初步研究

应用美国Ａｂｂｏｔｔ公司Ｓｉｍｏｎｓ等人报道的引物序列，以逆转录套式聚合酶链反应（ＲＴ－ｎＰＣＲ）检测３８例甲型肝炎病毒（ＨＡＶ）和乙型肝炎病毒（ＨＢＶ）指标均阴性的慢性肝炎患者血中的庚型肝炎病毒核酸（ＧＢＶ－Ｃ／ＨＧＶＲＮＡ）。２０例健康供血员血清作为对照，同时用ＲＴ－ＰＣＲ法测丙型肝炎病毒核酸（ＨＣＶＲＮＡ），结果３８例慢性肝炎患者中４例ＧＢＶ－Ｃ／ＨＧＶＲＮＡ阳性，其中２例同时有ＨＣＶＲＮＡ阳性。表明本地区有ＧＢＶ－Ｃ／ＨＧＶ感染存在。     

乙、丙型肝炎病毒重叠感染的慢性肝病患者肝组织和血清中的病毒检测

为了探讨乙型和丙型肝炎病毒（ＨＢＶ和ＨＣＶ）重叠感染者病毒相互干扰现象，对４４例患者血清检测诊断为ＨＢＶ和ＨＣＶ感染的慢性肝病患者，用原位杂交法检测了肝组织中ＨＢＶＤＮＡ和ＨＣＶＲＮＡ。２８例患者肝组织ＨＢＶＤＮＡ和ＨＣＶＲＮＡ同时阳性，两者阳性信号分布类型比较无明显差异（Ｐ＞０．０５），血清ＨＢｅＡｇ阳性和阴性组中肝组织中的ＨＢＶＤＮＡ和ＨＣＶＲＮＡ检出率无明显差异（Ｐ＞０．０５）。８例血清ＨＢｓＡｇ阴性者，肝组织ＨＢＶＤＮＡ阳性５例，ＨＣＶＲＮＡ阳性３例。结果提示，ＨＢＶ和ＨＣＶ重叠感染肝组织损伤加重，可能诱导一种病毒呈现潜伏状态，但不是病毒清除。     

烟台市售食品黄曲霉毒素污染状况及膳食暴露评估

目的 了解烟台市售食品黄曲霉毒素污染状况及居民膳食来源暴露风险水平。方法 免疫亲和层析高效液相色谱法测定样品中黄曲霉毒素,点评估方法估算人群黄曲霉毒素暴露量。结果 检测的市售食品中AFB1检出率为4.19%（19/453）,超标率为0.22%（1/453）,均值为0.86 μg/kg。AFB2、AFG1、AFG2和AFM1检出率分别为2.13%（9/423）、1.65%（7/423）、0.95%（4/423）和41.90%（44/105）,均值分别为0.29、0.64、0.33和 0.03 μg/kg。食品中存在AFB1、AFB2、AFG1和AFG2多重污染情况。AFB1的检出均值占到黄曲霉毒素(AFB1、AFB2、AFG1和AFG2)均值总和的47.18%。AFB1、AFB2、AFG1、AFG2和AFM1的日膳食暴露量分别为4.326、1.733、3.143、2.423和0.168 ng/（kg·bw·d）。AFB1、AFB2、AFG1、AFG2和AFM1的膳食暴露贡献率分别占到总体的36.69%、14.70%、26.65%、20.55%和1.42%。谷类及其制品的膳食暴露贡献最大,食用植物油的贡献次之。结论 AFB1总体检出率和均值均高于AFB2、AFG1和AFG2,是主要的污染品种。谷类及其制品和食用植物油是主要的AFB1、AFB2、AFG1和AFG2膳食暴露来源。乳制品是主要的AFM1的膳食暴露来源。烟台市居民AFB1和AFM1膳食暴露导致肝癌发病率为0.101/10万人和0.004/10万人。     

伏马菌素与黄曲霉毒素对SD大鼠联合毒性的研究

目的探讨伏马菌素 B_1(fumonisin B_1,FB_1)和黄曲霉毒素 B_1(aflatoxin B_1,AFB_1)对SD 大鼠的联合毒性作用。方法雄性 SD 大鼠按体重分为5组,每组12只,分别灌胃给予受试物(100μg/kg bw FB_1、100μg/kg bw AFB_1、100μg/kg bw FB_1+100μg/kg bw AFB_1、50μg/kg bw FB_1+50μg/kg bw AFB_1、蒸馏水),连续灌胃30d,观察动物的生长发育、食物利用情况、血液学、血生化指标及脏器组织病理学的改变情况。结果实验结束时100μg/kg bw FB_1+100μg/kg bw AFB_1组体重增重为(164.9±19.8)g,食物利用率为(25.3±1.6)%,低于实验对照组体重增重为(203.7±17.1)g,食物利用率为(28.1±1.2)%,也低于其余各实验组(P<0.05),而其余各染毒组与实验对照组间的差异无统计学意义(P>0.05);各实验组动物肝功能指标血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)、γ-谷氨酰胺转移酶(γ-GT)水平升高,且 FB_1+AFB_1组的升高程度较单独给予 FB_1和 AFB_1严重;同时 FB_1+AFB_1高剂量组动物肝脏、肾脏重量降低,肝脏出现明显病理变化,血清中超氧化物歧化酶(SOD)活力降低,丙二醛(MDA)水平升高等。结论两种真菌毒素存在联合毒性作用。本研究结果为进一步探讨两种真菌毒素同时暴露对人群健康的危害与联合作用。     

Associations of serum aflatoxin B1-lysine adduct level with socio-demographic factors and aflatoxins intake from nuts and related nut products in Malaysia

Aflatoxins are one of the major risk factors in the multi-factorial etiology of human hepatocellular carcinoma. Therefore, the information on aflatoxins exposure is very important in the intervention planning in order to reduce the dietary intake of aflatoxins, especially among the children. This study investigated the relationship between aflatoxin B(1) (AFB(1)) lysine adduct levers in serum and socio-demographic factors and dietary intake of aflatoxins from nuts and nut products in Penang, Malaysia. A cross-sectional field study was conducted in five districts of Penang. A survey on socio-demographic characteristics was administered to 364 healthy adults from the three main ethnic groups (Malay, Chinese and Indian). A total of 170 blood samples were successfully collected and tested for the level of AFB(1)-lysine adduct. 97% of the samples contained AFB(1)-lysine adduct above the detection limit of 0.4 pg/mg albumin and ranged from 0.20 to 23.16 pg/mg albumin (mean±standard deviation=7.67±4.54 pg/mg albumin; median=7.12 pg/mg albumin). There was no significant association between AFB(1)-lysine adduct levels with gender, district, education level, household number and occupation when these socio-demographic characteristics were examined according to high or low levels of AFB(1)-lysine. However, participants in the age group of 31-50 years were 3.08 times more likely to have high AFB(1) levels compared to those aged between 18 and 30 years (P=0.026). Significant difference (P=0.000) was found among different ethnic groups. Chinese and Indian participants were 3.05 and 2.35 times more likely to have high AFB(1) levels than Malay. The result of AFB(1)-lysine adduct suggested that Penang adult population is likely to be exposed to AFB(1) but at a level of less than that needed to cause direct acute illness or death.     

The sustained development of preneoplastic lesions depends on high protein intake.

The effects of sequential alterations in the feeding of two levels of dietary protein (5% and 20% casein) on the postinitiation development of aflatoxin B1- (AFB1) induced gamma-glutamyl transpeptidase-positive (GGT+) preneoplastic foci were examined. Weanling male Fischer 344 rats fed AIN-76A diet (20% protein) were administered 10 intragastric doses of AFB1 (1 dose/day during the 14-day dosing period excluding weekends) at 250 micrograms/kg body wt (initiation). After AFB1 tissue clearance, rats were randomly assigned to dietary treatment groups. During the next 12 weeks (promotion), they developed AFB1-induced GGT+ preneoplastic lesions. The 12-week promotion period was subdivided into four three-week periods, during which rats were fed isocaloric diets containing 20% casein during all four periods (20:20:20:20), 5% casein during all four periods (5:5:5:5), or sequentially altered casein levels (20:5:20:5 and 5:20:5:20). Rats were killed at 3,6,9, and 12 weeks to examine the dependence of GGT+ foci development on protein intake. Animals fed 5% casein diets developed significantly fewer (p < 0.01) GGT+ foci than animals fed 20% casein diets despite greater total caloric intake. Similarly, in the intervention groups, preneoplastic development was enhanced when the 20% casein diet was fed and inhibited when the 5% casein diet was fed. These results indicate that the sustained development of AFB1-induced preneoplastic foci depends on a high protein intake. Alternatively, these results suggest that low protein intake inhibits lesion development.     

Inhibition of aflatoxin production and growth of Aspergillus parasiticus by Cuminum cyminum, Ziziphora clinopodioides, and Nigella sativa essential oils

Aflatoxins are highly toxic and carcinogenic metabolites produced by Aspergillus parasiticus on food and agricultural commodities. Natural products may control the production of aflatoxins. The aims of this study were to evaluate the effects of the essential oils (EOs) of Cuminum cyminum, Ziziphora clinopodioides, and Nigella sativa on growth and aflatoxins production by A. parasiticus. Minimal inhibitory concentrations (MICs) and minimal fungicidal concentrations (MFCs) of the EOs were determined and compared with each other. Determination of aflatoxins (AFB(1), AFB(2), AFG(1), and AFG(2)) was performed by immunoaffinity column extraction using reverse phase-high performance liquid chromatography. The major oil components were α-pinene (30%) in C. cyminum, pulegone (37%) in Z. clinopodioides, and trans-anthol (38.9%) in N. sativa oils. In broth microdilution method, C. cyminum oil exhibited the strongest activity (MIC(90): 1.6; MFC: 3.5?mg/mL), followed by Z. clinopodioides (MIC(90): 2.1; MFC: 5.5?mg/mL) and N. sativa (MIC(90): 2.75; MFC: 6.25?mg/mL) oils against A. parasiticus (p<0.05). Aflatoxin production was inhibited at 0.25?mg/mL of C. cyminum and Z. clinopodioides oils, of which that of C. cyminum was a stronger inhibitor. C. cyminum EO caused significant reductions in values of 94.2% for AFB(1), 100% for AFB(2), 98.9% for AFG(1), 100% for AFG(2), and 97.5% for total aflatoxin. It is concluded that the EOs of C. cyminum, Z. clinopodioides, and N. sativa could be used as natural inhibitors in foods at low concentrations to protect from fungal and toxin contaminations by A. parasiticus.     

Carcinogenic effects of aflatoxin B1 among wheat handlers

Background:

Epidemiological studies have demonstrated that serum aflatoxin B1 (AFB1) is a hepatocarcinogenic mycotoxin and contributor to the high rate of hepatocellular carcinoma (HCC). The prevalence of liver cancer in Egypt is particularly worrisome. In a registry-based analysis of occupational risk for HCC, significant excesses were observed especially for grain mill workers.

Objective:

The aim of this study was to assess the hepatic carcinogenicity of AFB1 in wheat handlers.

Methods:

Serum AFB1/albumin (AFB1/Alb), alpha-fetoprotein (AFP), alpha-l-fucosidase (AFU), and arginase were estimated in exposed wheat handlers including millers and bakers. The control group was composed of non-occupationally exposed workers.

Results:

AFB1/Alb and AFU were significantly higher among workers employed as bakers compared to mill workers and controls. Mill workers had higher levels of AFB1/Alb than the controls. AFB1/Alb, AFP, and AFU were all significantly higher and arginase was significantly lower among HCC cases compared to the other groups. There was a significant correlation between AFU and AFB1/Alb in bakers and between AFP and AFB1/Alb in HCC cases. Arginase was inversely correlated with AFB1/Alb in HCC cases. AFB1/Alb was significantly correlated with the duration of exposure in bakers.

Conclusion:

Wheat handlers exposed to Aspergillus flavus have a high risk of elevated serum AFB1/Alb levels and AFU.     

Protective effect of soybean saponins and major antioxidants against aflatoxin B1-induced mutagenicity and DNA-adduct formation

Saponins from various plant sources have been suggested as possible anticarcinogens. Major dietary sources of saponins include legumes such as soybeans. This study was performed to determine the effect of soybean saponins on aflatoxin B(1)(AFB(1))-induced mutagenicity and AFB(1)-DNA adduct formation using Salmonella typhimurium and human liver hepatoma (HepG2) cells, respectively. Major antioxidants including L-ascorbic acid, alpha-tocopherol, all-trans-retinol, and butylated hydroxytoluene (BHT), previously reported to possess antimutagenic activity, were used as test materials to evaluate the relative effectiveness of saponins. Results indicated antimutagenicity was in the order of BHT > saponins > alpha-tocopherol > L-ascorbic acid. Soybean saponins exerted a significant effect, inhibiting the mutagenicity of AFB(1) by 52%, 64%, and 81% at concentrations of 600, 900, and 1,200 microg per plate, respectively. The amount of tritiated AFB(1) metabolites-DNA adducts formed in HepG2 cells was significantly reduced when cells were preincubated with 10 or 30 microg/ml of test materials. Soybean saponins inhibited AFB(1)-DNA adduct formation by 50.1% at a concentration of 30 microg/ml, whereas L-ascorbic acid and BHT reduced adduct formation by 38.4% and 32.6%, respectively, at the same concentrations. These results indicate that soybean saponins possess not only a significant antimutagenic activity but a strong inhibitory action against carcinogen-induced DNA damages. Soybean saponins possibly block the initiation stage of carcinogenesis, and further studies are required to elucidate the mechanisms of action.     

植物乳杆菌F22对肝脏和肠道微生物菌群的影响研究

目的研究植物乳杆菌F22(Lactobacillus.plantarum F22)对肝脏和肠道微生物菌群的影响。方法 5 w龄雄性昆明小鼠60只,随机分为:低剂量植物乳杆菌F22[1×109 CFU/0.5ml磷酸缓冲液(PBS)]+黄曲霉毒素B1(AFB1)(250μg/kg bw)、高剂量植物乳杆菌F22(1×1010 CFU/0.5 ml PBS)+AFB1(250μg/kg bw)、AFB1(250μg/kg bw)、和无菌PBS液4组,Ⅰ、Ⅱ、Ⅲ、Ⅳ分别灌胃对应试物共10 d,之后,测定血清指标、肝组织结构及肠道菌群数量。结果 AFB1攻毒使小鼠血清白蛋白(ALB)、球蛋白(GLOB)和总蛋白(TP)含量均降低(P0.05);谷草转氨酶(GOT)、谷丙转氨酶(GPT)和碱性磷酸酶(AKP)活性极显著升高(P0.01);肝脏组织切片可见肝细胞广泛性变性和坏死,肠道菌群失调,乳酸菌、双歧杆菌和总厌氧菌数量下降,肠杆菌、肠球菌和总需氧菌数量升高。在灌胃植物乳杆菌F22后,以上现象均得到改善,并随剂量增加恢复效果更好。结论植物乳杆菌F22作为肠道益生菌对AFB1中毒小鼠肝脏和肠道微生态失调具有缓解作用。     

上海地区小麦中霉菌毒素的污染调查

采集上海郊县1995年的小麦样品100份．应用薄层层析法检测黄曲霉毒素B1（AFB1），用气相色谱法检测镰刀菌毒素脱氧雪腐镰刀菌烯酸（DON）和雪腐镰刀菌烯酸（NIV）。样品中DON、NIV和AFB1的污染率分别为53．0％、35．0％和45．0％，平均含量分别为280．9μg/kg、103．4μg／kg和0．86μg/kg。有17份样品同时检出AFB1，DON和NIV，可见镰刀菌毒素和黄曲霉毒素可共同污染粮食。本次调查我们还发现小麦中DON和NIV的含量存在相关关系（r＝0．55．P＜0．01），而AFB1与这两种毒素之间不存在相关关系（r＜0.10，P＞0.05）。     

Variability in aflatoxin-albumin adduct levels and effects of hepatitis B and C virus infection and glutathione S-transferase M1 and T1 genotype

Exposure to aflatoxin B1 (AFB1), an important cofactor in the etiology of hepatocellular carcinoma in Taiwan, is influenced by dietary and other factors. The present study examined the intraindividual variability in AFB1-albumin adducts, the most reliable long-term biomarker of AFB1 exposure, and whether the baseline or follow-up adduct levels and the intraindividual variability in adduct levels are modified by endogenous and environmental factors. The study measured AFB1-albumin adduct levels among 264 healthy male residents of three townships (Hu-Hsi, Ma-Kung, and Pai-Hsa) of Penghu Islets, Taiwan, at two different time points with a median interval of 1.68 years (range 1.00-3.17 years). There was a generalized reduction in the adduct levels, with the median values being 22.1 pmol/mg (range 5.0-355.8 pmol/mg) at time 1 and 14.3 pmol/mg (range 5.0-205.2 pmol/mg) at time 2. This intraindividual variability in adduct levels was inversely associated with the age of subjects and the time interval between the two blood draws. The variability in adduct levels was lower among subjects in Hu-Hsi and Pai-Hsa townships as compared to those in Ma-Kung. No significant association was observed for the intraindividual variability in AFB1-albumin adducts with regard to the season when blood was drawn. There was also no significant association between intraindividual variability and hepatitis B surface antigen, anti-hepatitis C virus (anti-HCV), glutathione S-transferase (GST) M1, or GSTT1 status. In conclusion, we found substantial intraindividual variability in the AFB1 exposure (as determined by AFB1-albumin adducts) in Taiwan, which was probably more likely related to dietary or other environmental influences rather than to endogenous factors (e.g., hepatitis B/C viral infection or GST M1/T1 genetic status).