Genetic polymorphisms in GSTM1, GSTP1, and GSTT1 and the risk for breast cancer: results from the Shanghai Breast Cancer Study and meta-analysis.

PURPOSE: We studied the relation of breast cancer to common deletion mutations in GSTM1 and GSTT1 and the functional Ile(105)Val polymorphism in GSTP1 in a large, population-based case-control study conducted in China and performed a meta-analysis to summarize the literature. EXPERIMENTAL DESIGN: In the case-control study, a total of 1144 breast cancer cases and 1221 community controls were genotyped for GSTM1, GSTP1, and GSTT1 using PCR-based methods. Associations of genotypes and breast cancer were evaluated in logistic regression models. Meta-analysis odds ratios (ORs) were estimated using a fixed effects model. RESULTS: In the case-control study, associations were null for GSTM1 [age-adjusted OR 0.97, 95% confidence interval (CI): 0.82-1.14] and GSTT1 (OR 0.97, 95% CI: 0.83-1.15). A significant increase in risk was observed among homozygotes for the variant Ile(105)Val polymorphism (OR 1.92, 95% CI: 1.21-3.04). No combined effects of GSTM1, GSTP1, and GSTT1 genotypes or interactions with potential effect modifiers were detected. All results were similar in pre- and postmenopausal women and for early versus advanced stage breast cancer. The meta-analysis, based predominantly on Caucasian women, supported null results for the homozygous deletion variant in GSTM1 (summary OR 1.05; combining 19 studies) and GSTT1 (summary OR 1.11; 15 studies). Meta-analysis results for the homozygous GSTP1 variant indicated no overall association (summary OR 1.04; 10 studies), although results varied significantly across studies (P = 0.009). CONCLUSIONS: This large case-control study provides strong support for earlier studies showing no overall association of the GSTM1 and GSTT1 deletion polymorphisms with breast cancer risk. The GSTP1 variant may be relevant to breast cancer risk in Asian populations.     

Population-based case-control study of CYP11A gene polymorphism and breast cancer risk.

The CYP11A gene encodes the cholesterol side-chain cleavage enzyme (P450scc) that catalyzes the first and rate-limiting step for the biosynthesis of sex hormones. A pentanucleotide repeat [(TAAAA)n] polymorphism in the 5' of the CYP11A gene has been reported to be related to the risk of polycystic ovary syndrome, an inherited endocrine disorder characterized by hyperandrogenemia. We investigated the association of this polymorphism with breast cancer risk in a population-based case-control study conducted among Chinese women in Shanghai. Genotype assays were completed for 1015 incident breast cancer cases and 1082 community controls. Three common alleles with 4, 6, or 8 TAAAA repeats were identified in the study population. The frequency of the 8 repeat allele was more common in cases (12.6%) than controls (8.5%) (odds ratio = 1.6, 95% confidence interval = 1.3-1.9; P < 0.0001). Compared to subjects who did not carry this allele, adjusted odds ratios were 1.5 (95% confidence interval = 1.2-1.9) and 2.9 (1.3-6.7) (P for trend, <0.001), respectively, for those who carried one and two copies of this allele. This positive association was observed in both pre- and postmenopausal women and all strata defined by major breast cancer risk factors, including years of menstruation, body mass index, and waist-to-hip ratio. The results from this study indicate that the TAAAA repeat polymorphism near the promoter region of the CYP11A gene may be an important susceptibility factor for breast cancer risk.     

A population-based case-control study of the Arg399Gln polymorphism in DNA repair gene XRCC1 and risk of breast cancer.

XRCC1 (X-ray repair cross-complementing group 1) is a base excision repair protein that plays a central role in the repair of DNA base damage and strand breaks. A common polymorphism (Arg-->Gln) at codon 399 of the XRCC1 gene has been previously linked to functional changes of the gene product and risk of cancers. We evaluated the association between XRCC1 Arg399Gln polymorphism and breast cancer risk in the population-based Shanghai Breast Cancer Study involving 1088 cancer patients and 1182 community controls. Genomic DNA from peripheral blood was used in genotyping assays, and exposure information and anthropometrics were collected through in-person interview. Plasma estrogen and sex hormone-binding globulin (SHBG) levels were measured for 190 postmenopausal breast cancer patients who had donated a pretreatment blood sample and 407 postmenopausal controls. Conditional logistic regression model was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) adjusting potential confounders. Approximately 27% of controls carried the variant allele (Gln), and cases and controls had a similar distribution for both allele type and genotype of this polymorphism. We found that 7.8% of cases and 6.3% of controls were homozygous for the variant allele, resulting in an OR of 1.20 (95% CI, 0.85-1.69). The OR was slightly higher among younger women [<45 years of age (OR, 1.39; 95% CI, 0.82-2.36)] than older women [> or = 45 years of age (OR, 1.07; 95% CI, 0.68-1.67)], but neither OR was statistically significant. No modifying effect of major breast cancer risk factors, including years of menstruation, body mass index, waist:hip ratio, and blood estrogen levels, was noted. Homozygosity for the variant Gln allele was associated with an elevated risk of postmenopausal breast cancer among subjects with a higher blood level of SHBG (OR, 3.27; 95% CI, 1.16-9.20) and a reduced risk among those with a lower level of SHBG (OR, 0.60; 95% CI, 0.18-1.97). The overall results of the study suggest that Arg399Gln polymorphism of the XRCC1 gene alone may not play a substantial role in the risk of breast cancer among Chinese women.     

Preclinical pharmacology of the natural product anticancer agent 10-hydroxycamptothecin, an inhibitor of topoisomerase I

Purpose: 10-Hydroxycamptothecin (HCPT) is an indole alkaloid isolated from a Chinese tree, Camptotheca acuminata, and has a wide spectrum of anticancer activity in vitro and in vivo mainly through inhibitory effects on topoisomerase I. HCPT has been shown to be more potent and less toxic than camptothecin and has recently undergone clinical trials. To determine how HCPT might be best used as an anticancer agent, preclinical studies of the pharmacokinetics, tissue distribution, metabolism and elimination of HCPT in rats were undertaken. Methods: HCPT was administered to rats by i.v. bolus injection at doses of 1, 3, and 10 mg/kg body weight. HCPT (lactone and carboxylate) and its metabolites in plasma, urine, feces, and various tissues were quantitated by reversed-phase HPLC. Pharmacokinetic parameters were then estimated. Results: Following i.v. administration at doses of 3 or 10 mg/kg, the plasma concentration-time profile for lactone HCPT could be best described by a three-compartment model, with terminal elimination half-lives of 140.4 and 428.6 min, respectively. A two-compartment model was used to fit the plasma concentration-time curve at 1 mg/kg, with a terminal elimination half-life of 30.5 min. Carboxylate HCPT had a longer half-life than the lactone form of HCPT. During the initial 6 h after dosing, urinary excretion was the major route of elimination, and fecal excretion became the major route of elimination thereafter. HCPT was widely distributed to various tissues including the enterohepatic system, kidney, and bone marrow. The lactone form of HCPT was detectable in various tissues examined up to 72 h after dosing at all the three test doses. HCPT glucuronides were present in plasma, urine, feces and various tissues. No significant toxicity was observed at doses of 1 or 3 mg/kg. Polyuria and hematuria were observed only during the initial 3 h after dosing at 10 mg/kg. Conclusions: Prolonged elimination of HCPT in vivo may have a significant impact on its therapeutic effects. HCPT is metabolized to its carboxylate form and glucuronides. Dose-dependent toxicity was observed with i.v. administration of HCPT. The results of this study should be useful in the design of future human trials with this anticancer drug. Received: 6 September 1996 / Accepted: 15 July 1997     

超声造影显像模式对实验兔心肌血管通透性的影响

目的观察心肌声学造影中,高机械指数诊断超声在连续发射及间歇触发条件下,对兔心肌血管通透性的影响。方法14只新西兰白兔随机分为两组：超声连续显像组和超声时间触发组。经耳缘静脉注射脂氟显微泡造影剂,0．5ml／kg。GE Vivid 7超声诊断仪,机械指数MI为1．3,采用连续显像和间隔2s触发显像方式作用于兔心脏。伊文思蓝（Evans blue,EB）作为血管通透性示踪剂。通过比较室性早搏的次数、EB心肌染色和漏出量、淤点淤斑的评分等指标,评价超声显像模式对心肌血管通透性的影响。结果诊断超声连续发射和间隔2s触发的条件下,出现的室性早搏次数无明显差异,但在触发条件下,出现多次的短阵室性心动过速,EB的漏出量较多（P〈0．01）,EB透壁性较明显,视觉评分等级高于连续发射组（P〈0．01）。结论在心肌声学造影中,高MI诊断超声可以使兔心肌微血管通透性增高,间歇触发显像方式产生的生物学效应较显著。     

Role of TGF-β1 and its Receptors in Breast Carcinogenesis： Evaluation of Gene Expression Pattems and Clinical Implications

OBJECTIVE Transforming growth factor β1 （TGF-β1） is a multifunc- tional cytokine that may play an important role in tumor development and progression. METHODS We evaluated gene expression patterns of TGF-β1 and its receptors [transforming growth factor β type Ⅰ receptor （TβR- Ⅰ ） and transforming growth factor β type Ⅱ receptor （TβR- Ⅱ ）] in tumor tissue from patients with breast cancer or with benign breast diseases （BBD） and adjacent normal tissue from the patients with breast cancer. Included in the study were 527 breast cancer patients and 213 BBD patients who participated in the Shanghai Breast Cancer Study. RESULTS The expression levels of the TGF-β1, TβR- Ⅰ and TβR-Ⅱ genes in breast tissue were quantified using real-time PCR. TIER- Ⅱ expression in cancer tissue was decreased by over 50% as compared to either adjacent normal tissue from the same patients or benign tumor tissue from BBD patients （p〈0.001）. TGF-β1 expression was lower by approximately 20% in cancer tissue compared to adjacent normal tissue （p=0.14） or to benign tumor tissue （p=0.002）. Although TβR-Ⅰ expression was also reduced in cancer tissue compared to adjacent normal tissue, or benign tumor tissue, the magnitude of the reduction was less apparent than that for TβR- Ⅱ. Compared to patients with the lowest tertile value for TβR- Ⅱ, patients with median tertile value for TβR- Ⅱ had more favorable overall survival （HR 0.47, 95% CI 0.27-0.85） and disease-free survival （HR 0.65, 95% CI 0.39-1.06）. No apparent associations, however, were observed between TGF-β1 or TβR- Ⅰ expression and overall or disease-free survival. CONCLUSION The results from this study support the hypothesis that a decreased level of TβR-Ⅱ gene expression, and thus reduced TGF-β1 sensitivity, is related to breast tumor progression.     

Immunohistochemical expressions of Ki-67, cyclin D1, beta-catenin, cyclooxygenase-2, and epidermal growth factor receptor in human colorectal adenoma: a validation study of tissue microarrays.

BACKGROUND: Tissue microarray (TMA) holds promise as a high-throughput method for the analysis of biomarkers in tissue specimens. The validity and reliability of this method, however, may vary for different biomarkers in different tissue specimens. OBJECTIVES: In this study, we evaluated the validity and reliability of using TMA to assess biomarkers in colorectal adenomas. METHODS: Sixty-three consecutive patients with colorectal adenomas were recruited in this study. Two TMA blocks were constructed using four punches from each adenoma (one periphery, one deep, and two middle zones). The immunostaining of five markers (Ki-67, cyclin D1, beta-catenin, cyclooxygenase-2, and epidermal growth factor receptor) was analyzed, and the concordance between data obtained from TMAs and standard whole-tissue sections was evaluated by Spearman's correlation and kappa analysis. RESULTS: Colorectal adenoma exhibited zonal, heterogeneous expression patterns for all five markers. The concordance rates for the semiquantitative evaluation of markers between data from TMAs and whole sections ranged from 87% to 93% with corresponding kappa statistics of 77% to 90%. In addition, both quantitative and semiquantitative methods were used to score TMA sections, and good correlations between these two methods were shown for all five markers with intraclass correlation coefficients ranging from 0.5 to 0.8. CONCLUSION: Our study indicates that TMA can be used to reliably assess the expression levels of Ki-67, cyclin D1, beta-catenin, cyclooxygenase-2, and epidermal growth factor receptor in colorectal adenoma tissues.