Endocrine metabolic disorders in patients with breast cancer, carriers of BRCA1 gene mutations.

Two groups of breast cancer patients (53±2 years) in clinical remission receiving no specific therapy were examined: group 1, with BRCA1 gene mutations (N=11) and group 2, without mutations of this kind (N=11). The two groups did not differ by insulinemia and glycemia, insulin resistance index, blood levels of thyrotropic hormone, sex hormone-binding globulin, insulin-like growth factor-1, triglycerides, or lipoproteins. In group 1, blood estradiol level was higher. Intensive glucose-induced generation of reactive oxygen species in these patients was associated with a decrease of cholesterolemia, of the C-peptide/insulin proportion, and a trend to higher urinary excretion of 4-hydroxyestrone, one of the most genotoxic catecholestrogens. BRCA1 gene mutations in breast cancer patients were associated with signs of estrogenization and a pro-genotoxic shift in the estrogen and glucose system, which could modulate the disease course and requires correction.

Excretion of estrogens, catecholestrogens and phytoestrogens in carriers of BRCA1 gene mutations: effects of metformin.

BRCA1 gene mutation is associated with a combination of excessive aromatase activity/expression, predominantly estrogen receptor-negative phenotypes of tumors, and only scarce information about estrogen contents in body fluids. In the present work, isotope dilution capillary gas chromatography/mass spectrometry was used to study urinary excretion of estrogens, their catechol metabolites, and phytoestrogens in 22 women (11 with BCRA1 gene mutations and 11 without these mutations) in average 5.1+/-0.4 years before surgery for breast cancer. BCRA1 mutation carriers (including 3 premenopausal females) compared with respective controls showed significantly higher urinary estradiol and estrone excretion and a trend to an increased 2-OH-E2 excretion. In the subgroup of untreated postmenopausal women, BCRA1 mutation carriers showed a trend to increased estradiol and estrone excretion and to a higher value of the mean levels of all estrogen metabolites tested. The treatment after the baseline laboratory investigation of 6 women from postmenopausal group with the antidiabetic biguanide metformin for 3 months was associated with decreases in the excretion rates of 4-hydroxyestradiol, 2-methoxyestradiol, and 16-epiestriol and did not influence phytoestrogen excretion. The decrease in 2-methoxyestrogen excretion was more consistent in women without BCRA1 mutations than in BCRA1 mutation carriers. The data suggest the possibility that aromatase complex activation in BCRA1 mutation carriers is combined with increases in both, estrogen metabolism into catecholestrogens and their inactivation by methoxylation, and that metformin may affect both of these pathways.

Evaluation of the proportion of hormonal and progenotoxic effects of estrogens and glucose in cancer patients.

he progenotoxic (G, generation of reactive oxygen forms in mononuclears) and hormonal (H, reactive insulinemia) effects of oral glucose, on the one hand, and the same effects of estradiol (10(-8)and 10(-5)M) in vitro on blood mononuclears (G: by comet tail length; H: by expression of AMP kinase and TNF and IL-6 secretion), on the other, were compared with consideration for the concepts on endocrine genotoxic switch-over in patients with breast cancer and endometrial cancer in remission. Coculturing of mononuclears with estradiol in general led to an increase in comet tail and was associated with a trend to more intense expression of AMP kinase and IL-6 secretion. The reaction to estradiol (primarily in a concentration of 10(-8)M) evaluated by the expression of AMP kinase and TNF secretion was more intensive than the reaction evaluated by comet tail lengths or by percentage of cells with comets in women with predominating progenotoxic effect of glucose vs. hormonal effect. This fact can be used as a landmark in search for means for optimization of the status and proportion of effects in the estrogen and glucose systems.