Estrogens, Obesity, Inflammation, and Breast Cancer—What Is the Link?

Abstract

Our work on breast cancer concerns the role of local aromatase expression in the breast as the source of estrogen driving breast cancer development in the postmenopausal woman. 1,2 Following the menopausal transition, the ovaries cease to make estrogens, which then becomes the responsibility of extragonadal sites such as breast, bone, and brain. Work from our laboratory and others indicates that estrogen produced in these sites acts locally rather than systemically in a paracrine and intracrine fashion. 3,4 Thus, in the case of the breast, our goal has been to define the mechanisms whereby aromatase expression is regulated within the breast, with the translational goal of developing new breast-specific inhibitors of aromatase expression as improved endocrine therapy for breast cancer treatment and prevention. Aromatase in the Breast, Aging, and Breast CancerWithin the breast, aromatase expression occurs in the adipose mesenchymal cells and increases fourfold in the presence of a tumor. 3 This occurs in conjunction with differential promoter usage such that the gonadal proximal promoter PII dominates relative to the promoter I.4. [5][6][7] We and others have shown that this is because inflammatory factors such as prostaglandin E 2 produced by the tumorous epithelium Keywords ► estrogens ► obesity ► inflammation ► breast cancer AbstractIt gives me great pleasure to contribute to this special issue of Seminars which honors the career of Bruce Carr. As it happens, Bruce was my first Fellow upon my arrival at the Green Center for Reproductive Biology Sciences at UT Southwestern Medical Center in 1977. At that time, the Center was filled with luminaries of Reproductive Endocrinology, such as John Porter, Jack Johnston, Norman Gant, and of course the Director, Paul MacDonald, so to be given the responsibility of mentoring a new Fellow was a daunting responsibility. However, Bruce quickly rolled up his sleeves and plunged straight in, and we forged a relationship which led to some 36 manuscripts in 4 years. The first of these was entitled "The Role of Serum Lipoproteins in Steroidogenesis by the Human Fetal Adrenal Cortex," published in the Journal of Clinical Endocrinology and Metabolism, volume 49, pages 146-148, in 1979, and the authors were Simpson ER, Carr BR, Parker CR Jr, Milewich L, Porter JC, and MacDonald PC. Bruce quickly moved up the ranks of the Obstetrics/Gynecology Department to become full Professor and we went our separate ways professionally, but we remain close friends to this day. This special issue is indeed a worthy tribute to an outstanding career and especially to Bruce's role as editor-in-chief of Seminars which he has guided through the rapid evolution of the specialty, always maintaining a strong research focus and thus carrying on the rich tradition of the Green Center and the Obstetrics/Gynecology Department.

Body weight changes and duration of estrogen exposure modulate the evolution of hepatocellular adenomas after contraception discontinuation

“…Moreover, overweight and obesity are associated with an increased level of estrogen production due to the activation of aromatase in adipose tissue. [20,21] Consequently, we developed a simple scoring system from 0 to 4 based on the presence and duration of estrogen-based contraception and BMI at diagnosis. The score was built to reflect the amount of estrogen exposure over time.…”

“…Estrogen exposure in women is not only related to the use of estrogen‐based contraception but also the duration of use of contraception. Moreover, overweight and obesity are associated with an increased level of estrogen production due to the activation of aromatase in adipose tissue 20,21. Consequently, we developed a simple scoring system from 0 to 4 based on the presence and duration of estrogen‐based contraception and BMI at diagnosis.…”

“…This score was proposed based on physiological variables known to modulate the estrogen exposure in the literature. [20,21] The cutoff for the length of uses of oral contraception was based on the median value observed in our study and the cutoff for the BMI was based on the value used to define overweight and obesity.…”

“…A score of estrogen exposure in women (0–4 points) was constructed based on BMI at diagnosis and the duration of exposure to estrogen‐based contraception: BMI < 25 kg/m 2 , 0 point; BMI of 25–30 kg/m 2 , 1 point; BMI > 30 kg/m 2 , 2 points; no oral contraception, 0 points; duration of oral contraception less than median length of 12 years, 1 point; and duration of oral contraception greater than median length of 12 years, 2 points. This score was proposed based on physiological variables known to modulate the estrogen exposure in the literature 20,21. The cutoff for the length of uses of oral contraception was based on the median value observed in our study and the cutoff for the BMI was based on the value used to define overweight and obesity.…”

Direct and indirect associations between dietary magnesium intake and breast cancer risk

“…Oestrogen is derived mainly from the ovaries in premenopausal women and from aromatase in postmenopausal women; both of these sources have been found to be regulated by pro-inflammatory cytokines in distinct ways 57,58 . Differences in the oestrogen biosynthesis mechanisms may account for the different effects of inflammatory marker levels on breast cancer risk between pre- and postmenopausal women 57,59–61 . Dietary calcium intake has been suggested to have an interactive effect with magnesium on breast cancer risk.…”