PUFA Increases Estrogen
PUFA Inhibit Glucuronidation
PUFA Promote Cancer
Maternal PUFA Intake Increases Breast Cancer Risk in Female Offspring
Estrogen and Bowel Transit Time
Study: Acquired Breast Cancer Risk Spans Multiple Generations
A 1994 publication (B. Zumoff, “Hormonal profiles in women with breast cancer,” Obstet. Gynecol. Clin. North. Am. (U.S.) 21(4), 751-772) reported that there are four hormonal features in women with breast cancer: diminished androgen production, luteal inadequacy, increased 16-hydroxylation of estradiol, and increased prolactin. The 16-hydroxylation converts estradiol into estriol. -Ray Peat, PhD
Obstet Gynecol Clin North Am. 1994 Dec;21(4):751-72.
Hormonal profiles in women with breast cancer.
The literature findings on endogenous hormonal profiles in women with breast cancer are reviewed in detail. It is concluded that four sets of findings are valid: (1) diminished adrenal androgen production, probably genetic, in women with premenopausal breast cancer; (2) ovarian dysfunction (luteal inadequacy plus increased testosterone production) in breast cancer at all ages; (3) increased 16 alpha-hydroxylation of estradiol in breast cancer at all ages; and (4) evidence that prolactin is a permissive risk factor for breast cancer, and that the pregnancy-induced decrease in prolactin levels may account for the protective effect of early pregnancy against breast cancer.
J Natl Cancer Inst. 1986 Sep;77(3):613-6.
Endogenous sex hormones, prolactin, and breast cancer in premenopausal women.
Meyer F, Brown JB, Morrison AS, MacMahon B.
Forty-one women with breast cancer and 119 controls participated in a case-control study of the relation of endogenous sex hormones to breast carcinoma in premenopausal women. During the follicular phase of the menstrual cycle, one overnight urine specimen was collected. During the luteal phase, urine and blood specimens were obtained. 17 beta-Estradiol, sex hormone-binding globulin, progesterone, and prolactin were measured in plasma, whereas estrogen metabolites (estrone, estradiol, and estriol) and pregnanediol were assessed in the urine. Breast cancer was associated with high-plasma estradiol and prolactin and with low progesterone. Similar but weaker associations were observed for urinary estrogens and pregnanediol in the luteal phase.
J Mammary Gland Biol Neoplasia. 1998 Jan;3(1):49-61.
Role of hormones in mammary cancer initiation and progression.
Russo IH, Russo J.
Breast cancer, the most frequent spontaneous malignancy diagnosed in women in the Western world, is a classical model of hormone dependent malignancy. There is substantial evidence that breast cancer risk is associated with prolonged exposure to female hormones, since early onset of menarche, late menopause, hormone replacement therapy and postmenopausal obesity are associated with greater cancer incidence. Among these hormonal influences a leading role is attributed to estrogens, either of ovarian or extra-ovarian origin, as supported by the observations that breast cancer does not develop in the absence of ovaries, ovariectomy causes regression of established malignancies, and in experimental animal models estrogens can induce mammary cancer. Estrogens induce in rodents a low incidence of mammary tumors after a long latency period, and only in the presence of an intact pituitary axis, with induction of pituitary hyperplasia or adenomas and hyperprolactinemia. Chemicals, radiation, viruses and genomic alterations have all been demonstrated to have a greater tumorigenic potential in rodents. Chemical carcinogens are used to generate the most widely studied rat models; in these models hormones act as promoters or inhibitors of the neoplastic process. The incidence and type of tumors elicited, however, are strongly influenced by host factors. The tumorigenic response is maximal when the carcinogen is administered to young and virgin intact animals in which the mammary gland is undifferentiated and highly proliferating. The atrophic mammary gland of hormonally-deprived ovariectomized or hypophysectomized animals does not respond to the carcinogenic stimulus. Administration of carcinogen to pregnant, parous or hormonally treated virgin rats, on the other hand, fails to elicit a tumorigenic response, a phenomenon attributed to the higher degree of differentiation of the mammary gland induced by the hormonal stimulation of pregnancy. In women a majority of breast cancers that are initially hormone dependent are manifested during the postmenopausal period. Estradiol plays a crucial role in their development and evolution. However, it is still unclear whether estrogens are carcinogenic to the human breast. The apparent carcinogenicity of estrogens is attributed to receptor-mediated stimulation of cellular proliferation. Increased proliferation could result in turn in accumulation of genetic damage and stimulation of the synthesis of growth factors that act on the mammary epithelial cells via an autocrine or paracrine loop. Alternatively estrogens may induce cell proliferation through negative feedback by removing the effect of one or several inhibitory factors present in the serum. Multidisciplinary studies are required for the elucidation of the mechanisms responsible for the initiation of breast cancer. Understanding of such mechanisms is indispensable for developing a rational basis for its prevention and control.
Tumori. 2000 Jan-Feb;86(1):12-6.
Factors of risk for breast cancer influencing post-menopausal long-term hormone replacement therapy.
Chiechi LM, Secreto G.
The advantages of hormone replacement therapy (HRT) are well documented in contrasting the symptomatology of climacterium and in reducing morbidity and mortality associated with coronary heart disease and osteoporotic fractures of postmenopausal age. However, growing evidence points to increased breast cancer risk in HRT long-term users, and the adverse effect would, obviously, overwhelm any other benefit. At present, the risk/benefit ratio of HRT is an object of hot debate, and we feel it necessary and urgent to select women who can safely benefit from HRT and women whose risk of breast cancer can be perilously increased by the raised hormonal levels related to HRT. We have reviewed studies on the breast cancer risk in HRT users and data on the interaction between steroid hormones and breast cancer. Reasoning that the outcome of mammary cancer can be increased by hormonal overstimulation of the breast, we have focused on those factors of risk that could be further enhanced by the exogenous hormonal stimulus of HRT, so as to cause a further significant increase in the risk of breast cancer. We conclude that some biologic and clinical markers, namely android obesity, bone density, mammographic density, androgen and estrogen circulating levels, alcohol consumption, benign breast disease, and familiarity, should be carefully considered before prescribing long-term HRT. Our analysis suggests that HRT could increase the risk of breast cancer and useless in preventing coronary heart disease and osteoporotic fractures when administered in women with positivity for one or more of these markers.
Endocrinol Metab Clin North Am. 2011 Sep;40(3):473-84, vii. Epub 2011 Jun 29.
Estrogen carcinogenesis in breast cancer.
Many studies have reported a correlation between elevated estrogen blood levels and breast cancer and this observation has raised controversy concerning the long-term use of hormonal replacement therapy. This review will not address further this controversial topic; but rather, this review focuses on the role of estrogen signaling in first, the normal development of the breast and second, how alterations of this signaling pathway contribute to breast cancer.
Ann N Y Acad Sci. 1988;538:257-64.
Possible relevance of steroid availability and breast cancer.
Bruning PF, Bonfrer JM.
The as yet circumstantial evidence for a central role of estrogens in the promotion of human breast cancer is supported by many data. However, it has not been possible to identify breast cancer patients or women at risk by abnormally elevated estrogen levels in plasma. The concept of available, i.e., non-SHBG bound sex steroid seems to offer a better understanding than total serum steroid levels do. We demonstrated that sex steroid protein binding is decreased by free fatty acids. This finding may help to explain how the affluent Western diet and sedentary life style is related to high incidence rates of breast cancer. We have postulated that it is especially the central (abdominal) type of obesity which may increase sex steroid availability. This mechanism could be important already at the age of breast development when the sensitivity to promotion seems relatively great. It may also explain the increased incidence rates which are observed in Western industrialized countries after menopause. It seems likely that other endocrine-related cancer, such as endometrial or prostatic carcinomas are influenced in an analogous way.
Environment and breast cancer risk:
Environmental Health 2012, 11:87
Breast cancer risk in relation to occupations with exposure to carcinogens and endocrine disruptors: a Canadian case–control study
James T Brophy, Margaret M Keith, Andrew Watterson, Robert Park, Michael Gilbertson, Eleanor Maticka-Tyndale, Matthias Beck, Hakam Abu-Zahra, Kenneth Schneider, Abraham Reinhartz, Robert DeMatteo and Isaac Luginaah
Endocrine disrupting chemicals and carcinogens, some of which may not yet have been classified as such, are present in many occupational environments and could increase breast cancer risk. Prior research has identified associations with breast cancer and work in agricultural and industrial settings. The purpose of this study was to further characterize possible links between breast cancer risk and occupation, particularly in farming and manufacturing, as well as to examine the impacts of early agricultural exposures, and exposure effects that are specific to the endocrine receptor status of tumours.
1006 breast cancer cases referred by a regional cancer center and 1146 randomly-selected community controls provided detailed data including occupational and reproductive histories. All reported jobs were industry- and occupation-coded for the construction of cumulative exposure metrics representing likely exposure to carcinogens and endocrine disruptors. In a frequency-matched case–control design, exposure effects were estimated using conditional logistic regression.
Across all sectors, women in jobs with potentially high exposures to carcinogens and endocrine disruptors had elevated breast cancer risk (OR = 1.42; 95% CI, 1.18-1.73, for 10 years exposure duration). Specific sectors with elevated risk included: agriculture (OR = 1.36; 95% CI, 1.01-1.82); bars-gambling (OR = 2.28; 95% CI, 0.94-5.53); automotive plastics manufacturing (OR = 2.68; 95% CI, 1.47-4.88), food canning (OR = 2.35; 95% CI, 1.00-5.53), and metalworking (OR = 1.73; 95% CI, 1.02-2.92). Estrogen receptor status of tumors with elevated risk differed by occupational grouping. Premenopausal breast cancer risk was highest for automotive plastics (OR = 4.76; 95% CI, 1.58-14.4) and food canning (OR = 5.70; 95% CI, 1.03-31.5).
These observations support hypotheses linking breast cancer risk and exposures likely to include carcinogens and endocrine disruptors, and demonstrate the value of detailed work histories in environmental and occupational epidemiology.
Intestinal flora, diet, and estrogen:
Rev Infect Dis. 1984 Mar-Apr;6 Suppl 1:S85-90.
Estrogens, breast cancer, and intestinal flora.
Epidemiologic evidence has linked diet to breast cancer, with the highest cancer rates observed in women who eat a high fat-low fiber diet. There is also substantial information, both clinical and experimental, that implicates estrogens in the etiology of breast cancer. A recent study from our laboratory has shown that diet influences levels of estrogens, and the main mechanism is metabolism of estrogens in the intestine. The intestinal microflora plays a key role in the enterohepatic circulation of estrogens by deconjugating bound estrogens that appear in the bile, thereby permitting the free hormones to be reabsorbed. By suppressing the microflora with antibiotic therapy, fecal estrogens increase and urinary estrogens decrease, changes indicating diminished intestinal reabsorption. A low fat-high fiber diet is associated with similar findings-high fecal estrogens and low urinary estrogens. It appears that the microflora plays a key role in the metabolism of female sex hormones.