The cystic fibrosis transmembrane regulator (CFTR) gene encodes the synthesis of a protein of the same name, which functions as a direct activator of anionic transport. Chloride is the most abundant anion; as an antagonist of Na+ and K+, it provides electroneutrality of cell membranes at rest; together with cations, it serves as an important osmolyte and forms water flow across cell membranes for transepithelial secretion.Glandular cells in CF trap Cl– and Na+, and the prodused secretion is excessively viscous. Subnormal CFTR activity leads to stagnation of mucociliary clearance, inhibition of intestinal transport.In addition to exocrine disorders, CFTR mutations are associated with a decrease in volume, mass, increased apoptosis of β-cells of the pancreas, a significant suppression of insulin exocytosis in response to stimulation with glucose and glucagon-like peptide-1, hyperglucagonemia against the background of a defect in the suppression of α-cell function by insulin, but a decrease in maximum capacity α-cells.Deficiency and progressive decline in bone mineral density is an expected secondary manifestation of CF due to pancreatic exocrine insufficiency with malabsorption of nutrients and fat-soluble vitamins. However, in patients with the F508del mutation, a significant decrease in the synthesis of OPG, COX-2, PGE2 in the osteoblastic formation, and an increase in the activity of the antianabolic NF-kB were found. We are talking about a defect in the canonical signaling pathway (Wnt/β-catenin), which regulates the expression of genes-activators of osteoblastogenesis, dissociation of the stages of physiological bone remodeling.In addition to congenital bilateral or unilateral aplasia of the vas deferens, an increase in the frequency of CFTR mutations is also found in non-obstructive azoospermia, oligo-, astheno- and teratospermia. CFTR is involved in the entry of HCO3– into Sertoli cells to trigger cAMP-dependent transcription and its defects lead to suppression of FSH-dependent gene expression of spermatogenesis, loss of sequence in the Wnt cascade, destruction of the PGE2-dependent transepithelial interaction and, as a consequence, the blood-testicular barrier.CF is characterized, along with classical signs, by endocrine dysfunction of the pancreas, osteoporosis with suppression of osteoblastogenesis, and a defect in spermatogenesis.

Oncogenesis can be caused by an increase in the activity of genes responsible for initiating tumor growth in stem or progenitor cells, as well as a reduction in the functioning of suppressor genes. Endogenous estrogen exposure is associated with an increased risk of breast cancer in both pre- and postmenopausal women. The most important step in the understanding of the pathogenesis of breast cancer was the development of the theory of the switching of estrogen’s effect from hormonal to genotoxic, in which the main culprits of carcinogenesis are not chemical metabolites of estrogens, but their derivatives, corresponding to chemical procarcinogens according to their damaging characteristics. The origin of these substances and the formation of estrogen genotoxicity lies in the disruption of the inactivation process of catechol estrogens in methylation reactions. The main epigenetic modification of the human genome is the methylation of cell DNA molecules. DNA methylation does not alter the primary sequence of nucleotides, but is necessary for the functional suppression of certain genes. The phenomenon of hypomethylation-hypermethylation underlies the long-term silencing of various genes, including tumor suppressor genes. Nutrition and a lifestyle associated with smoking and the consumption of excessive quantities of alcohol determine estrogen metabolism and the availability of methyl groups in the body, as well as epigenetic changes in the DNA of the genome. The assessment of individual risk of breast cancer on the basis of an assay for the expression and methylation of the COMT gene responsible for estrogen metabolism seems relevant.

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The article presents a draft of clinical recommendations for the diagnosis and treatment of primary hyperparathyroidism in adult patients, which provides a modern examination algorithm, discusses the basic principles of laboratory, instrumental diagnostics and treatment approaches.

Methylation of catechol estrogens is catalyzed by catechol-O-methyltransferase. Synthesis and activity of this enzyme is encoded by the COMT gene. Downregulation of COMT expression is responsible for the risk of developing estrogen-dependent tumors. Obesity is a factor determining the overall methylation status in the body. There are two main types of adipose tissue differing in their functional and metabolic characteristics, as well as the microscopic structure: white adipose tissue (WAT) and brown adipose tissue (BAT). Lipolysis of WAT is controlled by hormone-sensitive lipase, which depends is catecholamine dependent. BAT is a special type of adipose tissue whose main function is to produce heat. Activation of β3-adrenergic receptors by catecholamines, both at the central and peripheral levels, is the primary mechanism regulating thermogenesis in mature BAT. Obese patients develop adipose tissue hypoxia, as well as WAT and BAT dysfunction. Adrenergic stimulation of thermogenesis is unclaimed because of «whitening» of brown adipocytes, which manifests itself as degradation of mitochondria. Redirection of stimulation of hormone-sensitive lipase by catecholamines to WAT and the increased need to enhance COMT expression are the potential consequences of modifying the BAT metabolism. Estrogens are natural modulators of lipolysis (as they selectively affect activity of hormone-sensitive lipase) and regulators of BAT thermogenesis. Obesity is accompanied by elevated synthesis of estrone. However, in postmenopausal women it is characterized by a decrease in the total mass and activity of BAT. The role of BAT in the progression or inhibition of growth of the estrogen-dependent tumor tissue at premenopausal and postmenopausal age has not been studied yet and is of interest to researchers. The possible correlation between the activity of brown adipocytes and the COMT expression level is discussed in the context of the risk of developing benign breast dysplasia and cancer.