MATERIALS AND METHODS: We assessed the association between plasma phospholipid fatty acids and breast cancer risk in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition study. Sixty fatty acids were measured by gas chromatography in pre-diagnostic plasma phospholipids from 2982 incident breast cancer cases matched to 2982 controls. Conditional logistic regression models were used to estimate relative risk of breast cancer by fatty acid level. The false discovery rate (q values) was computed to control for multiple comparisons. Subgroup analyses were carried out by estrogen receptor (ER) and progesterone receptor expression in the tumours.
RESULTS: A high level of palmitoleic acid [odds ratio (OR) for the highest quartile compared with the lowest OR (Q4-Q1) 1.37; 95% confidence interval (CI), 1.14-1.64; P for trend = 0.0001, q value = 0.004] as well as a high desaturation index (DI16) (16:1n-7/16:0) [OR (Q4-Q1), 1.28; 95% C, 1.07-1.54; P for trend = 0.002, q value = 0.037], as biomarkers of de novo lipogenesis, were significantly associated with increased risk of breast cancer. Levels of industrial trans-fatty acids were positively associated with ER-negative tumours [OR for the highest tertile compared with the lowest (T3-T1)=2.01; 95% CI, 1.03-3.90; P for trend = 0.047], whereas no association was found for ER-positive tumours (P-heterogeneity =0.01). No significant association was found between n-3 polyunsaturated fatty acids and breast cancer risk, overall or by hormonal receptor.
CONCLUSION: These findings suggest that increased de novo lipogenesis, acting through increased synthesis of palmitoleic acid, could be a relevant metabolic pathway for breast tumourigenesis. Dietary trans-fatty acids derived from industrial processes may specifically increase ER-negative breast cancer risk.
METHODS: A case-control study was nested in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. A total of 2008 incident invasive breast cancer cases (estrogen receptor (ER)+, n = 1622; ER-, n = 386), matched 1:1 to controls, were included in the analysis. Women were predominantly postmenopausal at blood collection (77%); postmenopausal women included users and non-users of postmenopausal hormone therapy (HT). Serum OPG was quantified with an electrochemiluminescence assay. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression.
RESULTS: The associations between OPG and ER+ and ER- breast cancer differed significantly. Higher concentrations of OPG were associated with increased risk of ER- breast cancer (top vs. bottom tertile RR = 1.93 [95% CI 1.24-3.02]; p trend = 0.03). We observed a suggestive inverse association for ER+ disease overall and among women premenopausal at blood collection. Results for ER- disease did not differ by menopausal status at blood collection (p het = 0.97), and we observed no heterogeneity by HT use at blood collection (p het ≥ 0.43) or age at breast cancer diagnosis (p het ≥ 0.30).
CONCLUSIONS: This study provides the first prospective data on OPG and breast cancer risk by hormone receptor subtype. High circulating OPG may represent a novel risk factor for ER- breast cancer.
METHODS: We analysed the relationship between pre-diagnostic prolactin levels and the risk of in situ breast cancer overall, and by menopausal status and use of postmenopausal hormone therapy (HT) at blood donation. Conditional logistic regression was used to assess this association in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, including 307 in situ breast cancer cases and their matched control subjects.
RESULTS: We found a significant positive association between higher circulating prolactin levels and risk of in situ breast cancer among all women [pre-and postmenopausal combined, ORlog2=1.35 (95% CI 1.04-1.76), Ptrend=0.03]. No statistically significant heterogeneity was found between prolactin levels and in situ cancer risk by menopausal status (Phet=0.98) or baseline HT use (Phet=0.20), although the observed association was more pronounced among postmenopausal women using HT compared to non-users (Ptrend=0.06 vs Ptrend=0.35). In subgroup analyses, the observed positive association was strongest in women diagnosed with in situ breast tumors<4 years compared to ≥4 years after blood donation (Ptrend=0.01 vs Ptrend=0.63; Phet=0.04) and among nulliparous women compared to parous women (Ptrend=0.03 vs Ptrend=0.15; Phet=0.07).
CONCLUSIONS: Our data extends prior research linking prolactin and invasive breast cancer to the outcome of in situ breast tumours and shows that higher circulating prolactin is associated with increased risk of in situ breast cancer.
METHODS: Associations between prediagnostic plasma levels of 17 primary, secondary, and tertiary bile acid metabolites (conjugated and unconjugated) and colon cancer risk were evaluated in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Bile acid levels were quantified by tandem mass spectrometry in samples from 569 incident colon cancer cases and 569 matched controls. Multivariable logistic regression analyses were used to estimate odds ratios (ORs) for colon cancer risk across quartiles of bile acid concentrations.
RESULTS: Positive associations were observed between colon cancer risk and plasma levels of seven conjugated bile acid metabolites: the primary bile acids glycocholic acid (ORquartile 4 vs quartile 1= 2.22, 95% confidence interval [CI] = 1.52 to 3.26), taurocholic acid (OR = 1.78, 95% CI = 1.23 to 2.58), glycochenodeoxycholic acid (OR = 1.68, 95% CI = 1.13 to 2.48), taurochenodeoxycholic acid (OR = 1.62, 95% CI = 1.11 to 2.36), and glycohyocholic acid (OR = 1.65, 95% CI = 1.13 to 2.40), and the secondary bile acids glycodeoxycholic acid (OR = 1.68, 95% CI = 1.12 to 2.54) and taurodeoxycholic acid (OR = 1.54, 95% CI = 1.02 to 2.31). By contrast, unconjugated bile acids and tertiary bile acids were not associated with risk.
CONCLUSIONS: This prospective study showed that prediagnostic levels of certain conjugated primary and secondary bile acids were positively associated with risk of colon cancer. Our findings support experimental data to suggest that a high bile acid load is colon cancer promotive.
METHODS: We conducted a nested case-control study in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to evaluate C-reactive protein (CRP), IL6, and EOC risk by tumor characteristics. A total of 754 eligible EOC cases were identified; two controls (n = 1,497) were matched per case. We used multivariable conditional logistic regression to assess associations.
RESULTS: CRP and IL6 were not associated with overall EOC risk. However, consistent with prior research, CRP >10 versus CRP ≤1 mg/L was associated with higher overall EOC risk [OR, 1.67 (1.03-2.70)]. We did not observe significant associations or heterogeneity in analyses by tumor characteristics. In analyses stratified by waist circumference, inflammatory markers were associated with higher risk among women with higher waist circumference; no association was observed for women with normal waist circumference [e.g., IL6: waist ≤80: ORlog2, 0.97 (0.81-1.16); waist >88: ORlog2, 1.78 (1.28-2.48), Pheterogeneity ≤ 0.01].
CONCLUSIONS: Our data suggest that high CRP is associated with increased risk of overall EOC, and that IL6 and CRP may be associated with EOC risk among women with higher adiposity.
IMPACT: Our data add to global evidence that ovarian carcinogenesis may be promoted by an inflammatory milieu.