1.
Schmidt, Julie A, et al.
(författare)
Insulin-like growth factor-I and risk of differentiated thyroid carcinoma in the European Prospective Investigation into Cancer and Nutrition
2014
Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - 1055-9965 .- 1538-7755. ; 23:6, s. 976-985
Tidskriftsartikel (refereegranskat) abstract
Background: Little is known about the causes of thyroid cancer, but insulin-like growth factor-I (IGF-I) might play an important role in its development due to its mitogenic and anti-apoptotic properties. Methods: This study prospectively investigated the association between serum IGF-I concentrations and risk of differentiated thyroid carcinoma in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition. 345 incident cases of differentiated thyroid carcinoma were individually matched to 735 controls by study centre, sex, and age, date, time, and fasting status at blood collection, follow-up duration, and for women menopausal status, use of exogenous hormones, and phase of menstrual cycle at blood collection. Serum IGF-I concentrations were measured by immunoassay, and risk of differentiated thyroid cancer in relation to IGF-I concentration was estimated using conditional logistic regression. Results: There was a positive association between IGF-I concentrations and risk of differentiated thyroid carcinoma: the odds ratio for a doubling in IGF-I concentration was 1.48 (95% confidence interval: 1.06 - 2.08; ptrend = 0.02). The positive association with IGF-I was stable over time between blood collection and cancer diagnosis. Conclusion: These findings suggest that IGF-I concentrations may be positively associated with risk of differentiated thyroid carcinoma. Impact: This study provides the first prospective evidence of a potential association between circulating IGF-I concentrations and risk of differentiated thyroid carcinoma and may prompt the further investigations needed to confirm the association.
2.
Chuang, Shu-Chun, et al.
(författare)
Circulating Biomarkers of Tryptophan and the Kynurenine Pathway and Lung Cancer Risk
2014
Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - 1055-9965 .- 1538-7755. ; 23:3, s. 461-468
Tidskriftsartikel (refereegranskat) abstract
Background: Imbalances in tryptophan metabolism have been linked to cancer-related immune escape and implicated in several cancers, including lung cancer. Methods: We conducted a nested case-control study within the European Prospective Investigation into Cancer andNutrition (EPIC) that included 893 incident lung cancer cases and 1,748matched controls. Circulating levels of tryptophan and six of its metabolites were measured and evaluated in relation to lung cancer risk. Results: Tryptophan (P-trend = 2 Chi 10(-5)) and the kynurenine/ tryptophan ratio (KTR; P-trend 4 Chi 10(-5)) were associated with lung cancer risk overall after adjusting for established risk factors. The ORs comparing the fifth and first quintiles (OR5th (vs. 1st)) were 0.52 [ 95% confidence interval (CI), 0.37-0.74] for tryptophan and 1.74 (95% CI, 1.24-2.45) for KTR. After adjusting for plasma methionine (available fromprevious work, which was strongly correlated with tryptophan), the associations of tryptophan (adjusted P-trend 0.13) and KTR (P-trend = 0.009) were substantially attenuated. KTR was positively associated with squamous cell carcinoma, the OR5th vs. 1st being 2.83 (95% CI, 1.62-4.94, P-trend -3 Chi 10(-5)) that was only marginally affected by adjusting for methionine. Conclusions: This study indicates that biomarkers of tryptophan metabolism are associated with subsequent lung cancer risk. Although this result would seem consistent with the immune system having a role in lung cancer development, the overall associations were dependent on methionine, and further studies are warranted to further elucidate the importance of these metabolites in lung cancer etiology. Impact: This is the first prospective study investigating the tryptophan pathway in relation to lung cancer risk.
