C. H. van Gils

Plasma carotenoids as biomarkers of intake of fruits and vegetables: individual-level correlations in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Objective:The aim in this study was to assess the association between individual plasma carotenoid levels (α-carotene, β-carotene, lycopene, β-cryptoxanthin, lutein, zeaxanthin) and fruit and vegetable intakes recorded by a calibrated food questionnaire (FQ) and 24-h dietary recall records (24HDR) in nine different European countries with diverse populations and widely varying intakes of plant foods.Design:A stratified random subsample of 3089 men and women from nine countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC), who had provided blood samples and dietary and other lifestyle information between 1992 and 2000, were included.Results:β-Cryptoxanthin was most strongly correlated with total fruits (FQ r=0.52, 24HDR r=0.39), lycopene with tomato and tomato products (FQ r=0.38, 24HDR r=0.25), and α-carotene with intake of root vegetables (r=0.39) and of total carrots (r=0.38) for FQ only. Based on diet measured by FQ and adjusting for possible confounding by body mass index (BMI), age, gender, smoking status, alcohol intake, and energy intake, the strongest predictors of individual plasma carotenoid levels were fruits (R partial 2=17.2%) for β-cryptoxanthin, total carrots (R partial 2=13.4%) and root vegetables (R partial 2=13.3%) for α-carotene, and tomato products (R partial 2=13.8%) for lycopene. For 24HDR, the highest R partial 2 was for fruits in relation to β-cryptoxanthin (7.9%).Conclusions:Intakes of specific fruits and vegetables as measured by food questionnaires are good predictors of certain individual plasma carotenoid levels in our multicentre European study. At individual subject levels, FQ measurements of fruits, root vegetables and carrots, and tomato products are, respectively, good predictors of β-cryptoxanthin, α-carotene, and lycopene in plasma.

Effect of mammographic breast density on breast cancer screening performance: a study in Nijmegen, the Netherlands.

STUDY OBJECTIVE: To study the implications of breast density on mammographic screening performance. DESIGN: Screening outcomes of women with dense breast patterns were compared with those of women with lucent breast patterns (dense > 25% densities, lucent < or = 25% densities); the women were screened in different periods (before/after improvement of the mammographic technique in 1982). SETTING: Nijmegen, the Netherlands, 1977-1994. PARTICIPANTS: Between 1977 and 1994, 73,525 repeat screenings were performed in 19,152 participants (aged 50-69 years) in the Nijmegen breast cancer screening programme (repeat screenings were defined as mammographic examinations that were preceded by an examination in the previous screening round). Participants were screened biennially with mammography. There were 258 screen detected and 145 interval cancers. MAIN RESULTS: Before 1982 (rounds 2-4) the predictive value of a positive screening test (PV+) was lower in women with dense breasts than in those with lucent breasts (dense 29% v lucent 52%, p = 0.003). Also, the ratio of screen detected cancers to the total number of screen detected plus interval cancers (as a proxy for sensitivity) was lower in this group (based on a one year interval: dense 63% v lucent 92%, p = 0.001 and based on a two year interval: dense 41% v lucent 68%, p = 0.002). Moreover, the survival rate was less favourable for those with dense breasts (p = 0.07). In rounds 5-10, there were no important differences with respect to PV+ (dense 66% v lucent 62%, p = 0.57) or survival (p = 0.48). Moreover, sensitivity based on a one year interval was nearly as high in women with dense breasts as in those with lucent breasts (85% v 86%, p = 0.75). However, based on a two year interval sensitivity was lower (dense 59% v lucent 72%, p = 0.04). CONCLUSIONS: In the early screening years (rounds 2-4) high breast density had an unfavourable effect on screening performance. Nowadays, the situation has improved with respect to PV+, survival and detecting tumours in dense breasts with a lead time of up to one year, but little improvement has occurred in the detection of tumours with a lead time greater than one year.

Polymorphisms of genes coding for insulin-like growth factor 1 and its major binding proteins, circulating levels of IGF-I and IGFBP-3 and breast cancer risk: results from the EPIC study

Insulin-like growth factor I (IGF-I) stimulates cell proliferation and can enhance the development of tumours in different organs. Epidemiological studies have shown that an elevated level of circulating IGF-I is associated with increased risk of breast cancer, as well as of other cancers. Most of circulating IGF-I is bound to an acid-labile subunit and to one of six insulin-like growth factor binding proteins (IGFBPs), among which the most important are IGFBP-3 and IGFBP-1. Polymorphisms of the IGF1 gene and of genes encoding for the major IGF-I carriers may predict circulating levels of IGF-I and have an impact on cancer risk. We tested this hypothesis with a case–control study of 807 breast cancer patients and 1588 matched control subjects, nested within the European Prospective Investigation into Cancer and Nutrition. We genotyped 23 common single nucleotide polymorphisms in IGF1, IGFBP1, IGFBP3 and IGFALS, and measured serum levels of IGF-I and IGFBP-3 in samples of cases and controls. We found a weak but significant association of polymorphisms at the 5′ end of the IGF1 gene with breast cancer risk, particularly among women younger than 55 years, and a strong association of polymorphisms located in the 5′ end of IGFBP3 with circulating levels of IGFBP-3, which confirms previous findings. Common genetic variation in these candidate genes does not play a major role in altering breast cancer risk in Caucasians.

Diet, serum insulin-like growth factor-I and IGF-binding protein-3 in European women

Objective:The aim of this study was to examine the relationship of diet with serum insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 in women.Design:Cross-sectional study.Setting and subjects:The population are 2109 women who were control subjects in a case–control study of breast cancer nested in the European Prospective Investigation into Cancer and Nutrition. Control subjects were randomly chosen among risk sets consisting of female cohort members alive and free of cancer (except non-melanoma skin cancer) at the time of diagnosis of the index case. Matching criteria were age at enrolment, follow-up time, time of the day of blood collection and study centre. Diet was measured through validated questionnaires. Serum hormone concentrations were measured by enzyme-linked immunosorbent assays. The relationship between serum IGF-I, IGFBP-3, and intake of nutrients and foods was explored by linear regression in models adjusted for energy intake, age, body mass index, smoking, physical activity, centre and laboratory batch.Results:Serum IGF-I levels were positively related to protein intake (P trend<0.001), but not related to energy, fat or carbohydrate intake. Positive relationships were observed with the intake of milk (P trend=0.007), calcium (P trend<0.001), magnesium (P trend=0.003), phosphorus (P trend<0.001), potassium (P trend=0.002), vitamin B6 (P trend=0.03), vitamin B2 (P trend=0.001) and inverse relationships with vegetables (P trend=0.02) and beta-carotene (P trend=0.02). IGFBP-3 was not related with most of the nutrients and foods in this study.Conclusions:In this population, circulating IGF-I is modestly related with the intake of protein and minerals, and with milk and cheese, while IGFBP-3 does not appear to be related with diet.

Postmenopausal serum sex steroids and risk of hormone receptor-positive and -negative breast cancer: a nested case-control study.

Prediagnostic endogenous sex steroid hormone levels have well established associations with overall risk of breast cancer. While evidence toward the existence of distinct subtypes of breast cancer accumulates, few studies have investigated the associations of sex steroid hormone levels with risk of hormone receptor [estrogen receptor (ER) and/or progesterone receptor (PR)] defined breast cancer. In a case–control study nested within the EPIC cohort (European Prospective Investigation into Cancer and Nutrition), estradiol, testosterone, and sex hormone–binding globulin levels were measured in prediagnostic serum samples from postmenopausal women not using hormone replacement therapy at blood donation. A total of 554 women who developed invasive breast cancer with information on receptor status were matched with 821 control subjects. Conditional logistic regression models estimated breast cancer risk with hormone concentrations according to hormone receptor status of the tumor. Sex steroid hormones were associated with risks of not only ER+PR+ breast cancer [estradiol OR for highest vs. lowest tertile = 2.91 (95% CI: 1.62–5.23), Ptrend = 0.002; testosterone OR = 2.27 (95% CI: 1.35–3.81), Ptrend = 0.002] but also of ER-PR- breast cancer [estradiol OR = 2.11 (95% CI: 1.00–4.46), Ptrend = 0.05; testosterone OR = 2.06 (95% CI: 0.95–4.46), Ptrend = 0.03], with associations appearing somewhat stronger in the receptor-positive disease. Serum androgens and estrogens are associated with risks of both hormone receptor–negative as well as receptor–positive breast tumors. Further research is needed to establish through which molecular pathways, and during which evolutionary stages of development, androgens and estrogens can promote the occurrence of both receptor-positive and -negative clinical breast tumors. Cancer Prev Res; 4(10); 1626–35. ©2011 AACR.

Body mass index, waist circumference and waist-hip ratio and serum levels of IGF-I and IGFBP-3 in European women

Objective:To examine the relationship between body mass index (BMI) and waist–hip ratio (WHR) with serum levels of insulin-like growth factor-I (IGF-I), and its binding protein (IGFBP)-3.Design:Cross-sectional study on 2139 women participating in a case–control study on breast cancer and endogenous hormones. Data on lifestyle and reproductive factors were collected by means of questionnaires. Body height, weight, waist and hip circumferences were measured. Serum levels of IGF-I and insulin-like binding protein (IGFBP)-3 were measured by enzyme-linked immunosorbent assays. Adjusted mean levels of IGF-I and IGFBP-3 across quintiles of BMI, waist circumference, and WHR were calculated by linear regression. Results were adjusted for potential confounders associated with IGF-I and IGFBP-3.Results:Adjusted mean serum IGF-I values were lower in women with BMI<22.5 kg/m2 or BMI>29.2 kg/m2 compared to women with BMI within this range (Pheterogeneity<0.0001, Ptrend=0.35). Insulin-like growth factor-I was not related to WHR after adjustment for BMI. IGF-binding protein-3 was linearly positively related to waist and WHR after mutual adjustment. The molar ratio IGF-I/IGFBP-3 had a non-linear relation with BMI and a linear inverse relationship with WHR (P trend=0.005).Conclusions:Our data confirm the nonlinear relationship of circulating IGF-I to total adiposity in women. Serum IGFBP-3 was positively related to central adiposity. These suggest that bioavailable IGF-I levels could be lower in obese compared to non-obese women and inversely related to central adiposity.

Fish consumption and breast cancer risk. The European Prospective Investigation into Cancer and Nutrition (EPIC)

There is current interest in fish consumption and marine omega‐3 (n‐3) fatty acids and breast cancer risk. Some in vitro and animal studies have suggested an inhibitory effect of marine n‐3 fatty acids on breast cancer growth, but the results from epidemiological studies that have examined the association between fish consumption and breast cancer risk in humans are inconsistent. We examined fish consumption and breast cancer risk in 310,671 women aged between 25 and 70 yr at recruitment into the European Prospective Investigation Into Cancer and Nutrition (EPIC). The participants completed a dietary questionnaire between 1992–98 and were followed up for incidence of breast cancer for a median of 6.4 yr. Hazard ratio for breast cancer by intake of total and lean and fatty fish were estimated, stratified by study centre and adjusted for established breast cancer risk factors. During follow‐up, 4,776 invasive incident breast cancers were reported. No significant associations between intake of total fish and breast cancer risk were observed, hazard ratio (HR) 1.01 (95% confidence interval [CI] 0.99–1.02; p = 0.28 per 10 g fish/day). When examining lean and fatty fish separately, we found a positive significant association only in the highest quintile for fatty fish (HR 1.13, 95% CI 1.01–1.26), but test for trend was not significant (p = 0.10). No associations with breast cancer risk were observed when the study participants were subdivided by menopausal status. Although the period of follow‐up is relatively short, the results provide no evidence for an association between fish intake and breast cancer risk.

Common Breast Cancer Susceptibility Variants in LSP1 and RAD51L1 Are Associated with Mammographic Density Measures that Predict Breast Cancer Risk

Background: Mammographic density adjusted for age and body mass index (BMI) is a heritable marker of breast cancer susceptibility. Little is known about the biologic mechanisms underlying the association between mammographic density and breast cancer risk. We examined whether common low-penetrance breast cancer susceptibility variants contribute to interindividual differences in mammographic density measures. Methods: We established an international consortium (DENSNP) of 19 studies from 10 countries, comprising 16,895 Caucasian women, to conduct a pooled cross-sectional analysis of common breast cancer susceptibility variants in 14 independent loci and mammographic density measures. Dense and nondense areas, and percent density, were measured using interactive-thresholding techniques. Mixed linear models were used to assess the association between genetic variants and the square roots of mammographic density measures adjusted for study, age, case status, BMI, and menopausal status. Results: Consistent with their breast cancer associations, the C-allele of rs3817198 in LSP1 was positively associated with both adjusted dense area (P = 0.00005) and adjusted percent density (P = 0.001), whereas the A-allele of rs10483813 in RAD51L1 was inversely associated with adjusted percent density (P = 0.003), but not with adjusted dense area (P = 0.07). Conclusion: We identified two common breast cancer susceptibility variants associated with mammographic measures of radiodense tissue in the breast gland. Impact: We examined the association of 14 established breast cancer susceptibility loci with mammographic density phenotypes within a large genetic consortium and identified two breast cancer susceptibility variants, LSP1-rs3817198 and RAD51L1-rs10483813, associated with mammographic measures and in the same direction as the breast cancer association. Cancer Epidemiol Biomarkers Prev; 21(7); 1156–. ©2012 AACR.

Oxidative stress status in patients with diabetes mellitus: relationship to diet

Objective: To investigate the relationship between dietary intakes and in vivo oxidative stress (OS) status in diabetic patients.Design: Case–control study.Setting: Outpatient-Clinic and Laboratory Endocrinology, University Antwerp.Subjects and methods: A total of 30 patients (24 type 1 diabetes mellitus (T1DM)/6 type 2 diabetes mellitus (T2DM) were asked to complete a 2 weekdays+1weekend day food consumption questionnaire during the week preceding their yearly diabetes control consultation, when samples were collected for the assay of oxidative stress (OS) (blood levels of antioxidants, peroxides, malondialdehyde (MDA) and minerals). Blood samples were also collected from 25 age- and sex-matched healthy controls.Results: Diabetic patients had lower glutathione (5.80±1.15 vs 6.75±1.03 μmol/g Hb in the controls, P=0.002) and higher MDA (0.687±0.212 vs 0.545±0.101 μmol/l, P=0.002). Although the group average intakes were within the Belgian RDA, intakes of fat >35% energy, fibre <15 g/1000 kcal, fruit <2 portions and vitamin E <10 mg/day were seen in more than 20 patients. Blood antioxidants did not correlate with intakes of energy, fat, protein or fibres or of their respective antioxidant. Vitamins A and E correlated with serum lipids (r=0.58, P <0.0005 between serum α-tocopherol and cholesterol). Blood peroxide levels were only related to intakes of saturated fat and cholesterol (P<0.05). In diabetic subjects but not in controls (P<0.05) MDA was related to glutathione and uric acid.Conclusions: In diabetic patients, blood levels of antioxidants are not related to their dietary intakes but to serum lipids. Levels of oxidative damage products are only related to intakes of saturated fats and cholesterol and to levels of endogenous antioxidants.

Methylation is less abundant in BRCA1-associated compared with sporadic breast cancer

BACKGROUND Promoter methylation is a common epigenetic mechanism to silence tumor suppressor genes during breast cancer development. We investigated whether BRCA1-associated breast tumors show cancer-predictive methylation patterns similar to those found in sporadic tumors. PATIENTS AND METHODS Quantitative multiplex methylation-specific PCR of 11 genes involved in breast carcinogenesis (RARB, RASSF1, TWIST1, CCND2, ESR1, SCGB3A1, BRCA1, BRCA2, CDKN2A, APC, CDH1) was carried out on 32 BRCA1-associated and 46 sporadic breast carcinomas and on normal breast tissue from seven BRCA1 mutation carriers and 13 non-carriers. RESULTS The extent of cumulative methylation increased with age (P < 0.001). The median cumulative methylation index (CMI) of all studied genes was significantly higher in tumors (89) than in normal tissue (13, P < 0.001). The median CMI was significantly lower in BRCA1-associated (59) than in sporadic breast tumors (122, P = 0.001), in estrogen receptor (ER)-negative tumors (73) than in ER-positive tumors (122, P = 0.005) and in lymph node-negative (77) compared with lymph node-positive tumors (137, P = 0.007). In subgroup analysis, the effect of a BRCA1 germline mutation on methylation proved to be independent of ER status, lymph node status and age. CONCLUSIONS These data indicate that BRCA1-associated breast cancers show less promoter methylation compared with sporadic breast carcinomas indicating a difference in disease etiology.