Breast cancer risk in premenopausal women is inversely associated with consumption of broccoli, a source of isothiocyanates, but is not modified by GST genotype

The role of vegetable consumption in relation to breast cancer risk is controversial. Anticarcinogenic compounds may be present only in specific vegetables, thereby attenuating findings for total vegetable intake. Cruciferous vegetables contain precursors of isothiocyanates (ITCs), which may be chemopreventive through potent inhibition of phase I, and induction of phase II enzymes, such as glutathione S-transferases (GSTs). We investigated associations between consumption of cruciferous vegetables, sources of ITCs, and breast cancer risk, and potential modification of relations by GSTM1 and GSTT1 genotypes. Cases (n = 740) were Caucasian women with incident breast cancer identified from all major hospitals in Erie and Niagara counties. Community controls (n = 810) were frequency matched to cases by age and county. An in-depth interview including a validated FFQ was administered in person. Odds ratios (ORs) and 95% CIs were used to estimate relative risks. Consumption of cruciferous vegetables, particularly broccoli, was marginally inversely associated with breast cancer risk in premenopausal women [4th quartile OR = 0.6, 95% CI (0.40-1.01), P = 0.058]. Associations were weaker or null among postmenopausal women. No significant effects of GST genotype on risk were observed in either menopausal group. These data indicate that cruciferous vegetables may play an important role in decreasing the risk of premenopausal breast cancer.     

GSTT1 genotype modifies the association between cruciferous vegetable intake and the risk of myocardial infarction

BACKGROUND: Cruciferous vegetables are a major dietary source of isothiocyanates that may protect against coronary heart disease. Isothiocyanates induce glutathione S-transferases (GSTs), polymorphic genes that code for enzymes that conjugate isothiocyanates, as well as mutagens and reactive oxygen species, to make them more readily excretable. OBJECTIVE: The objective of the study was to determine whether GST genotypes modify the association between cruciferous vegetable intake and the risk of myocardial infarction (MI). DESIGN: Cases (n = 2042) with a first acute nonfatal MI and population-based controls (n = 2042) living in Costa Rica, who were matched for age, sex, and area of residence, were genotyped for a deletion polymorphism in GSTM1 and GSTT1 and an Ile105Val substitution in GSTP1. Cruciferous vegetable intake and smoking status were determined by questionnaire. Odds ratios (ORs) and 95% CIs for MI were estimated by unconditional logistic regression. RESULTS: Compared with the lowest tertile of cruciferous vegetable intake, the highest tertile was associated with a lower risk of MI among persons with the functional GSTT1*1 allele (OR: 0.70; 95% CI: 0.58, 0.84) but not among those with the GSTT1*0*0 genotype (OR: 1.23; 95% CI: 0.83, 1.82) (P = 0.006 for interaction). This protective effect among those with the GSTT1*1 allele was greater for current smokers (OR: 0.54; 95% CI: 0.36, 0.79) than for nonsmokers. GSTP1 and GSTM1 did not modify the association between cruciferous vegetable intake and MI. CONCLUSIONS: Consumption of cruciferous vegetables was associated with a lower risk of MI among those with a functional GSTT1*1 allele, which suggests that compounds that are detoxified by this enzyme contribute to the risk of MI.     

Usual Cruciferous Vegetable Consumption and Ovarian Cancer: A Case-Control Study

Ovarian cancer is the fifth leading cause of cancer-related deaths among women, primarily due to diagnosis at late stages. Therefore, identification of modifiable risk factors for this disease is warranted. Using the Patient Epidemiology Data System (PEDS), collected from 1981 to 1998 at Roswell Park Cancer Institute, Buffalo, NY, we conducted a hospital-based, case-control analysis of self-reported cruciferous vegetable intake and ovarian cancer among 675 women with primary, incident ovarian cancer, and 1275 without cancer. Cruciferous vegetable intake was queried using a 44-item food frequency questionnaire (FFQ). Odds ratios (OR) and 95% confidence intervals (CI) were estimated with logistic regression, adjusting for age, body mass index (BMI), education, smoking status, parity, family history of ovarian cancer, total fruit consumption, total meat consumption, and total noncruciferous vegetable consumption. We observed a significant inverse association for women with highest vs. lowest intakes of total vegetables (OR = 0.65, 95% CI = 0.46–0.92), cooked cauliflower (OR = 0.82, 95% CI = 0.67–0.99), and cooked greens (OR = 0.63, 95% CI = 0.46–0.86) and an inverse, dose-dependent association between cooked cruciferous vegetables intake and ovarian cancer (for each additional ten servings per month, OR = 0.85, 95% CI = 0.76–0.96). These findings suggest that a diet that includes cruciferous vegetables could be an important modifiable risk factor for ovarian cancer.     

Fruits, vegetables, soy foods and breast cancer in pre- and postmenopausal Korean women: a case-control study

We carried out a case-control study to examine the relationship between fruits, vegetables, and soy foods intake with breast cancer risk in Korean women. Incident cases (n = 359) were identified through cancer biopsies and hospital-based controls (n = 708) were selected in the same hospitals. Subjects were asked to indicate usual dietary habits, which were assessed using a semi-quantitative food frequency questionnaire (98 items). Odds ratio (OR) and 95% confidence intervals (95% CI) were calculated by unconditional logistic regression after adjustment for additional confounding factors according to the menopausal status. High grape intake showed an inverse association of breast cancer in postmenopausal women (OR = 0.59, 95% CI = 0.35-0.95; p for trend = 0.05). High tomato intake was associated with reduced breast cancer risk in premenopausal women (OR = 0.59, 95% CI = 0.38-0.89, p for trend = 0.04). In postmenopausal women, green pepper intake showed an inverse association of breast cancer risk (OR = 0.60, 95% CI = 0.43-0.96, p for trend = 0.03). High soybean intake showed an inverse association of breast cancer in postmenopausal women (OR = 0.61, 95% CI = 0.34-0.89, p for trend = 0.02). Our study suggests that high intake of some fruits, vegetables, and soybeans may be associated with a reduced breast cancer risk.     

Cooked meat and risk of breast cancer--lifetime versus recent dietary intake

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HCAs) are carcinogens formed in or on the surface of well-done meat, cooked at high temperature. METHODS: We estimated breast cancer risk in relation to intake of cooked meat in a population-based, case-control study (1508 cases and 1556 controls) conducted in Long Island, NY from 1996 to 1997. Lifetime intakes of grilled or barbecued and smoked meats were derived from the interviewer-administered questionnaire data. Dietary intakes of PAH and HCA were derived from the self-administered modified Block food frequency questionnaire of intake 1 year before reference date. Unconditional logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Modest increased risk was observed among postmenopausal, but not premenopausal, women consuming the most grilled or barbecued and smoked meats over the life course (OR = 1.47; CI = 1.12-1.92 for highest vs. lowest tertile of intake). Postmenopausal women with low fruit and vegetable intake, but high lifetime intake of grilled or barbecued and smoked meats, had a higher OR of 1.74 (CI = 1.20-2.50). No associations were observed with the food frequency questionnaire-derived intake measures of PAHs and HCAs, with the possible exception of benzo(alpha)pyrene from meat among postmenopausal women whose tumors were positive for both estrogen receptors and progesterone receptors (OR = 1.47; CI = 0.99-2.19). CONCLUSIONS: These results support the accumulating evidence that consumption of meats cooked by methods that promote carcinogen formation may increase risk of postmenopausal breast cancer.     

Dietary intake of soy protein and tofu in association with breast cancer risk based on a case-control study

Soy food and its constituents may protect against breast cancer, but the association between soy intake and decreased breast cancer risk is inconsistent. We evaluated the relationship between breast cancer risk and the dietary intake of soy protein as measured by total soy food and tofu intake. Histologically confirmed cases (n = 362) were matched to controls by age (within 2 yr) and menopausal status. High soy protein intake was associated with reduced breast cancer risk in analyses adjusted for potential confounders including dietary factors among premenopausal women (odds ratio [OR] = 0.39 in the highest quintile, 95% confidence interval [CI] = 0.22-0.93, P for trend = 0.03) and postmenopausal women (OR = 0.22, 95% CI = 0.06-0.88, P for trend = 0.16). We also found an inverse association between total tofu intake and breast cancer risk among premenopausal women (for total tofu intake, OR = 0.23 in the highest quintile, 95% CI = 0.11-0.48, P for trend < 0.01; for at least 1 serving of tofu as the main ingredient per day, OR = 0.26, 95% CI = 0.13-0.55, P for trend < 0.01). We concluded that increased regular soy food intake at a level equivalent to traditional Korean consumption levels may be associated with a reduced risk of breast cancer, and this effect is more pronounced in premenopausal women.     

The risk of breast cancer associated with dietary lignans differs by CYP17 genotype in women

Lignans are plant compounds metabolized in the gut to produce the phytoestrogens enterolactone and enterodiol. Reduced breast cancer risks associated with higher urinary lignan excretion may be related to competitive inhibition of endogenous estrogens. Evidence exists that associations with reproductive risk factors for breast cancer differ according to cytochrome P450c17alpha (CYP17) genotype. Genetic variability in estrogen metabolism could affect lignan metabolism thereby modifying risk associations. We examined breast cancer risk, dietary lignans and CYP17 genotype among 207 women with primary, incident, histologically confirmed breast cancer and 188 controls frequency matched to cases by age and county of residence. Self-reported frequency of intake of 170 foods and beverages during the 2 y before the interview and other relevant data were collected by detailed in-person interviews. Dietary lignan intake was expressed as the sum of enterolactone and enterodiol production from foods. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression, adjusting for age, education and other breast cancer risk factors. Women in the highest tertile of dietary lignans tended to have reduced breast cancer risk (OR 0.45, 95% CI 0.20-1.01 and OR 0.59, 95% CI 0.28-1.27, pre- and postmenopausal women, respectively). Substantially reduced risks in the highest tertile of lignans were observed for premenopausal women with at least one A2 allele (OR 0.12, 95% CI 0.03-0.50). Our results suggest that CYP17 genotype may be important in modifying the effect on breast cancer risk of exogenous estrogens, particularly for premenopausal women.     

Intake of specific carotenoids and essential fatty acids and breast cancer risk in Montreal, Canada

BACKGROUND: Evidence from previous investigations into the possible role of dietary and serum carotenoid concentrations in the etiology of breast cancer is inconsistent. No study has examined the combined effect of carotenoids and essential fatty acids on the risk of breast cancer. OBJECTIVE: The objective was to assess the possible association between specific and total carotenoids and breast cancer risk and to evaluate the effect modification by diet-related fatty acids and lifestyle factors in the development of breast cancer. DESIGN: A population-based case-control study involving 414 incident cases and 429 controls was conducted in French Canadians in Montreal. Dietary intake was estimated with the use of a validated food-frequency questionnaire in face-to-face interviews. RESULTS: No significant association was apparent between any of the individual or total carotenoids and the risk of breast cancer after adjustment for major underlying determinants of breast cancer. In premenopausal women who ever smoked, an increased risk was related to alpha-carotene [odds ratio (OR) for the upper relative to the lowest quartiles of intake: 2.40; 95% CI: 0.90, 6.41; P for trend = 0.046]. Conversely, a reduced risk was related to beta-carotene (OR: 0.57; 95% CI: 0.26, 1.24; P for trend = 0.05) in women who never used hormone replacement therapy. In postmenopausal women, total carotenoids were positively associated with breast cancer risk in those with a high arachidonic acid intake (OR: 1.92; 95% CI: 0.93, 3.94; P = 0.028 for trend) and inversely associated in those with a high docosahexaenoic acid intake (OR: 0.52; 95% CI: 0.25, 1.07; P for trend = 0.054). CONCLUSION: These findings suggest that the combined high intake of total carotenoids and docosahexaenoic acid may reduce the risk of breast cancer.     

Serum polychlorinated biphenyls, cytochrome P-450 1A1 polymorphisms, and risk of breast cancer in Connecticut women

Recent epidemiologic studies have suggested that genetic polymorphisms in the cytochrome P-450 1A1 gene (CYP1A1) may affect the relation between environmental exposure to polychlorinated biphenyls (PCBs) and breast cancer risk. The authors report results from a case-control study evaluating the potential effect of gene-environment interaction between CYP1A1 and serum PCB levels on breast cancer risk among Caucasian women in Connecticut. The study included 374 case women with histologically confirmed breast cancer and 406 noncancerous controls with information on both serum PCB level and CYP1A1 genotype (1999-2002). Compared with women who had the homozygous wild-type CYP1A1 m2 genotype, significantly increased risks of breast cancer were found for women with the CYP1A1 m2 variant genotype (odds ratio (OR) = 2.1, 95% confidence interval (CI): 1.1, 3.9), especially postmenopausal women (OR = 2.4, 95% CI: 1.1, 5.0). Risks associated with the CYP1A1 m2 variant genotype were highest for all women (OR = 3.6, 95% CI: 1.5, 8.2) and postmenopausal women (OR = 4.3, 95% CI: 1.6, 12.0) with higher serum PCB levels (611-2,600 ng/g). The CYP1A1 m1 and m4 genotypes were not associated with breast cancer risk independently or in combination with PCB exposure. In summary, the CYP1A1 m2 genetic polymorphism was associated with increased risk of female breast cancer and may modify the relation between PCB exposure and breast cancer risk.     

Relation between insulin resistance and breast cancer among Chilean women

PURPOSE: In Chile, diabetes and breast cancer are important public health problems. The association between insulin resistance and breast cancer, however, remains largely unexplored. METHODS: We conducted a case-control study to assess the relationship of insulin resistance (IR) and breast cancer in Chilean premenopausal and postmenopausal women. We compared 170 women, 33 to 86 years old, with incident breast cancer and 170 normal mammography controls, matched by 5-year age interval. Plasmatic insulin and glucose were measured and IR was calculated by the homeostasis model assessment method. Anthropometric measurements and sociodemographic and behavioral data were also collected. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by multivariable conditional logistic regression. RESULTS: IR was independently associated with breast cancer in postmenopausal women (OR = 2.70, 95%CI = 1.10-6.63), but not in premenopausal women (OR = 0.84, 95%CI = 0.20-3.52). Obesity was not associated with breast cancer at any age (OR = 0.68, 95%CI = 0.39-1.20). CONCLUSION: In this sample, IR increased the risk of breast cancer among postmenopausal women.     

Cruciferous vegetables, genetic polymorphisms in glutathione S-transferases M1 and T1, and prostate cancer risk

Cruciferous vegetables contain anticarcinogenic isothiocyanates (ITCs), particularly the potent sulforaphane, which may decrease risk of prostate cancer through induction of phase II enzymes, including glutathione S-transferases (GSTs). We evaluated this hypothesis in a population-based, case-control study of prostate cancer, including 428 men with incident prostate cancer and 537 community controls. An in-person interview included an extensive food-frequency questionnaire. Genotyping for deletions in GSTM1 and GSTT1 was performed in a subset of men who provided blood. Intakes of cruciferous vegetables and of broccoli, the greatest source of sulforaphane, were associated with decreased prostate cancer risk at all levels above the lowest consumers [adjusted 4th quartile odds ratio (OR)=0.58; 95% confidence interval (CI)=0.38, 0.89, and 0.72 (95% CI=0.49, 1.06)], respectively. In relation to genotypes, there was a nonsignificant increase in risk with the GSTT1 null genotype (OR=1.51; 95% CI=0.98, 2.31) but no effects of GSTM1 genotype. However, men with GSTM1-present genotype and high broccoli intake had the greatest reduction in risk (OR=0.49; 95% CI=0.27, 0.89). Our findings provide evidence that two or more servings per month of cruciferous vegetables may reduce risk of prostate cancer, especially among men with GSTM1-present alleles, and are consistent with a role of dietary ITCs as chemopreventive agents against prostate cancer.     

Dietary Intake of Soy Protein and Tofu in Association With Breast Cancer Risk Based on a Case-Control Study

Soy food and its constituents may protect against breast cancer, but the association between soy intake and decreased breast cancer risk is inconsistent. We evaluated the relationship between breast cancer risk and the dietary intake of soy protein as measured by total soy food and tofu intake. Histologically confirmed cases ( n = 362) were matched to controls by age (within 2 yr) and menopausal status. High soy protein intake was associated with reduced breast cancer risk in analyses adjusted for potential confounders including dietary factors among premenopausal women (odds ratio [OR] = 0.39 in the highest quintile, 95% confidence interval [CI] = 0.22–0.93, P for trend = 0.03) and postmenopausal women (OR = 0.22, 95% CI = 0.06–0.88, P for trend = 0.16). We also found an inverse association between total tofu intake and breast cancer risk among premenopausal women (for total tofu intake, OR = 0.23 in the highest quintile, 95% CI = 0.11–0.48, P for trend < 0.01; for at least 1 serving of tofu as the main ingredient per day, OR = 0.26, 95% CI = 0.13–0.55, P for trend < 0.01). We concluded that increased regular soy food intake at a level equivalent to traditional Korean consumption levels may be associated with a reduced risk of breast cancer, and this effect is more pronounced in premenopausal women.     

Case-control study of lifetime physical activity and breast cancer risk

A population-based case-control study of 1,233 incident breast cancer cases and 1,237 controls was conducted in Alberta, Canada, in 1995-1997 to examine the effect of lifetime physical activity patterns on breast cancer risk. No associations between physical activity and breast cancer were found for premenopausal women. For postmenopausal women in the highest quartile (> or =161 metabolic equivalent (MET)-hours/week per year) versus the lowest quartile (<104.8 MET-hours/week per year) of lifetime total physical activity, the adjusted odds ratio was 0.70 (95% confidence interval (CI): 0.52, 0.94). When the risks associated with each type of activity were examined for postmenopausal women, household and occupational activity conferred the largest risk reductions (odds ratio (OR) = 0.57, 95% CI: 0.41, 0.79 and OR = 0.59, 95% CI: 0.44, 0.81, respectively, for highest vs. lowest quartiles of activity), while recreational activity was not associated with any risk reductions. For postmenopausal women, the authors found stronger risk reductions for those who were also nonsmokers (OR = 0.64, 95% CI: 0.46, 0.88), non-alcohol-drinkers (OR = 0.39, 95% CI: 0.11, 0.77), or nulliparous (OR = 0.22, 95% CI: 0.07, 0.70) when they compared the highest with the lowest quartile of lifetime total physical activity. This study provides evidence that lifetime total activity reduces risk of postmenopausal breast cancer.     

Intake of Energy-Dense Foods,Fast Foods,Sugary Drinks,and Breast Cancer Risk in African American and European American Women

Limiting energy-dense foods, fast foods, and sugary drinks that promote weight gain is a cancer prevention recommendation, but no studies have evaluated intake in relation to breast cancer risk in African American (AA) women. In a case-control study with 1692 AA women (803 cases and 889 controls) and 1456 European American (EA) women (755 cases and 701 controls), odds ratios (OR) and 95% confidence intervals (CI) for risk were computed, stratifying for menopausal and estrogen receptor (ER) status. Among postmenopausal EA women, breast cancer risk was associated with frequent consumption of energy-dense foods (OR = 2.95; 95% CI: 1.66–5.22), fast foods (OR = 2.35; 95% CI: 1.38–4.00), and sugary drinks (OR = 2.05; 95% CI: 1.13–3.70). Elevated risk of ER+ tumors in EA women was associated with energy-dense (OR = 1.75; 95% CI: 1.14–2.69) and fast foods (OR = 1.84; 95% CI: 1.22–2.77). Among AA women, frequent fast food consumption was related to premenopausal breast cancer risk (OR = 1.97; 95% CI: 1.13–3.43), and with ER+ tumors. Energy adjustment attenuated risk estimates in AA women, while strengthening them among EA women. Frequent consumption of energy-dense and fast foods that have poor nutritive value appeared to increase breast cancer risk in AA and EA women, with differences by menopausal status and ER status.     

Dietary fat, cooking fat, and breast cancer risk in a multiethnic population

Our objective was to examine the association between dietary fat intake, cooking fat usage, and breast cancer risk in a population-based, multiethnic, case-control study conducted in the San Francisco Bay area. Intake of total fat and types of fat were assessed with a food frequency questionnaire among 1,703 breast cancer cases diagnosed between 1995 and 1999 and 2,045 controls. In addition, preferred use of fat for cooking was assessed. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). High fat intake was associated with increased risk of breast cancer (highest vs. lowest quartile, adjusted OR = 1.35, 95% CI = 1.10-1.65, P(trend) < 0.01). A positive association was found for oleic acid (OR = 1.55, 95% CI = 1.14-2.10, P(trend) < 0.01) but not for linoleic acid or saturated fat. Risk was increased for women cooking with hydrogenated fats (OR = 1.58, 95% CI = 1.20-2.10) or vegetable/corn oil (rich in linoleic acid; OR = 1.30, 95% CI = 1.06-1.58) compared to women using olive/canola oil (rich in oleic acid). Our results suggest that a low-fat diet may play a role in breast cancer prevention. We speculate that monounsaturated trans fats may have driven the discrepant associations between types of fat and breast cancer.     

Association of caffeine intake and CYP1A2 genotype with ovarian cancer

Coffee and caffeine consumption has been associated with ovarian cancer risk in several epidemiological studies. CYP1A2 is a key enzyme in the metabolism of coffee and in the activation of heterocyclic aromatic compounds that may be carcinogenic. Data from a preliminary investigation conducted in Hawaii of 164 epithelial ovarian cancer cases and 194 controls were used to examine the hypothesis that coffee and caffeine intake increases the risk of ovarian cancer and that these relations are modified by the CYP1A2 high-inducibility A/A genotype. A personal interview and blood specimen were collected in the subjects' homes. A significant positive trend (p = 0.02) in the odds ratios (ORs) was found with increasing intake of caffeine but not with tea or soda. Regular coffee drinkers were at significantly increased risk (OR = 1.8, 95% confidence interval, CI = 1.1-2.8) of ovarian cancer compared with women who did not drink regular coffee. Women with any CYP1A2 C allele were at similar risk of ovarian cancer (OR = 1.1, 95% CI = 0.7-1.7) compared with women with the A/A genotype. The associations of caffeine and coffee intake with risk were stronger among women with the A/A genotype than among women with any C allele. Somewhat stronger relations of coffee and caffeine intake to risk were found among women with cruciferous vegetable consumption above the median and among cases with mucinous histology. These preliminary data suggest a modest positive association of caffeine and coffee consumption with the OR for ovarian cancer that may be modified by CYP1A2 genotype and exposures, such as cruciferous vegetable consumption, that influence CYP1A2 expression.     

Anthropometric variables in relation to risk of breast cancer in middle-aged women

BACKGROUND: Many epidemiological studies have assessed the relationships between anthropometric variables and breast cancer risk. However, methodological approaches for analysing these factors differ appreciably. Also, age when maximum height is achieved has been identified as a potential risk factor for breast cancer in premenopausal women, but this issue has not been studied in postmenopausal women. METHODS: The participants in this population-based case-control study were postmenopausal women 50-64 years of age from the general female population of western Washington State. It included 479 women with incident primary breast cancer and 435 controls. RESULTS: This study found that: (i) women who gained over 70 pounds since age 18 had an increased risk of breast cancer relative to those who stayed within 10 pounds of their weight at age 18 (odds ratio [OR] = 2.7; 95% CI: 1.5-4.9), (ii) women with body mass indices (BMI) below what is considered healthy had a decreased risk (OR = 0.4; 95% CI: 0.2-1.1) while women with a BMI in the obese range had an increased risk of breast cancer (OR = 1.4; 95% CI: 1.0-2.1), and (iii) women who reached their maximum height at or after the age of 18 had a decreased risk of breast cancer compared to women who reached their maximum height at age 13 or younger (OR = 0.7; 95% CI: 0.5-1.0). CONCLUSIONS: By examining various anthropometric variables using clinically relevant strata, a clearer picture of how these variables relate to postmenopausal breast cancer risk was developed. Similar to younger women, postmenopausal women who reached their maximum height at later ages had a decreased risk of breast cancer.     

血清有机氯农药DDT暴露、CYP1A1基因多态性与乳腺癌患病风险的病例对照研究

目的研究有机氯农药二氯二苯三氯乙烷(DDT)类物质暴露及细胞色素P4501A1m2突变基因型对女性乳腺癌患病风险的交互作用。方法运用病例对照研究方法,自2003年12月起至2004年9月止,收集组织病理学确诊乳腺癌的女性病例104例,社区来源的健康女性对照154名。采用问卷调查方法获取病例和对照乳腺癌相关危险因素的信息;用气相色谱-电子捕获(GC-ECD)方法检测血清样品中对,对-二氯二苯三氯乙烷(p,p’-DDT)、对,对-二氯二苯三氯乙烯(p,p’-DDE)的含量;用特异性聚合酶链反应(AS-PCR)法检测CYP1A1m2突变型基因;用logistic回归模型分析DDT类有机氯物质血清含量及CYP1A1m2突变基因型与乳腺癌患病风险的相对危险度(OR),以及二者的联合作用。结果病例和对照两组血清中的DDT的含量分别是(36.90±79.41)ng/ml和(50.60±150.70)ng/ml;DDE的含量分别是(7.43±11.10)ng/ml和(8.96±11.30)ng/ml,几何均数检验,两组间差异无统计学意义(P>0.05);CYP1A1m2型突变纯合型基因型(Val/Val)的调整OR=2.61,95%CI:1.00~6.80;绝经前乳腺癌病例与对照组中,携带Val突变基因型且DDT高暴露的OR=4.35,95%CI:1.140~16.950,参照等级是Ile/Ile野生纯合型基因且DDT低暴露。结论CYP1A1m2突变型基因型可能与乳腺癌有关,DDT暴露可能增加携带CYP1A1易感基因型的绝经前女性患乳腺癌的风险。     

Dietary flavonoid intake and breast cancer risk among women on Long Island

Flavonoids are found in a variety of foods and have anticarcinogenic properties in experimental models. Few epidemiologic studies have examined whether flavonoid intake is associated with breast cancer in humans. In this study, the authors investigated whether dietary flavonoid intake was associated with reduced risk of breast cancer in a population-based sample of US women. They conducted a case-control study among women who resided in Nassau and Suffolk counties on Long Island, New York. Cases and controls were interviewed about known and suspected risk factors and asked to complete a food frequency questionnaire regarding their average intake in the prior 12 months. A total of 1,434 breast cancer cases and 1,440 controls provided adequate responses. A decrease in breast cancer risk was associated with flavonoid intake; the decrease was most pronounced among postmenopausal women for flavonols (odds ratio (OR) = 0.54, 95% confidence interval (CI): 0.40, 0.73), flavones (OR = 0.61, 95% CI: 0.45, 0.83), flavan-3-ols (OR = 0.74, 95% CI: 0.55, 0.99), and lignans (OR = 0.69, 95% CI: 0.51, 0.94). The authors conclude that intake of flavonols, flavones, flavan-3-ols, and lignans is associated with reduced risk of incident postmenopausal breast cancer among Long Island women. These results suggest that US women can consume sufficient levels of flavonoids to benefit from their potential chemopreventive effects.     

Pooled analysis and meta-analysis of the glutathione S-transferase P1 Ile 105Val polymorphism and bladder cancer: a HuGE-GSEC review

The glutathione S-transferase P1 genotype (GSTP1) is involved in the inactivation of cigarette smoke carcinogens, and sequence variation in the gene may alter bladder cancer susceptibility. To examine the association between GSTP1Ile 105Val and bladder cancer, the authors undertook a meta- and pooled analysis. Summary crude and adjusted odds ratios and corresponding 95% confidence intervals were pooled by using a random-effects model. In the meta-analysis (16 studies, 4,273 cases and 5,081 controls), the unadjusted summary odds ratios for GSTP1 Ile/Val and Val/Val compared with GSTP1 Ile/Ile were 1.54 (95% confidence interval: 1.21, 1.99; p < 0.001) and 2.17 (95% confidence interval: 1.27, 3.71; p = 0.005). The association appeared to be the strongest in Asian countries. When the analysis was limited to European descendents (nine studies), the summary odds ratio decreased (odds ratio = 1.24, 95% confidence interval: 1.00, 1.52) (Q = 17.50; p = 0.02). All relevant data previously contributed to the International Study on Genetic Susceptibility to Environmental Carcinogens were pooled (eight studies, 1,305 cases and 1,558 controls). The summary odds ratios were similar to the ones from the meta-analysis. Case-only analyses did not detect an interaction between the GSTP1 genotype and smoking status (never/ever). GSTP1 Ile 105Val appears to be associated with a modest increase in the risk of bladder cancer.