Insulin and insulin-like growth factor and risk of postmenopausal estrogen receptor-positive breast cancer: a case-cohort analysis.

Background: Higher concentration of insulin-like growth factor-1 (IGF-1) increases postmenopausal breast cancer risk, but evidence for insulin and c-peptide is limited. Further, not all studies have accounted for potential confounding by biomarkers from other biological pathways, and not all were restricted to estrogen receptor (ER)-positive breast cancer.

Methods: This was a case-cohort study of 1,223 postmenopausal women (347 with ER-positive breast cancer) from the Melbourne Collaborative Cohort Study.

Sex-steroid hormones and risk of postmenopausal estrogen receptor-positive breast cancer: a case-cohort analysis.

Purpose: Sex-steroid hormones are associated with postmenopausal breast cancer but potential confounding from other biological pathways is rarely considered. We estimated risk ratios for sex-steroid hormone biomarkers in relation to postmenopausal estrogen receptor (ER)-positive breast cancer, while accounting for biomarkers from insulin/insulin-like growth factor-signaling and inflammatory pathways.

Methods: This analysis included 1,208 women from a case-cohort study of postmenopausal breast cancer within the Melbourne Collaborative Cohort Study.