Impact of some environmental chemical carcinogens on the incidence of hormone-dependent tumors and possible mechanisms of its realization (literary review)

Objective: We determined the possible effects of priority chemical environmental carcinogens on the incidence of hormone-dependent tumors and the mechanisms of their effect on the basis of the analysis of literature data and our own research. Results: The performed analysis demonstrates the scanity of the research devoted to the study of chemical carcinogens which are concerned only with the class of polycyclic aromatic hydrocarbons (PAH), benzo(a)pyrene (BP), atmospheric pollution, emissions from vehicles, the cadmium heavy metal and products of smoking containing these substances. The connection with PAH (BP) and the development of breast, ovarian cancer, cadmium with the development of breast, endometrial, ovarian cancer in women and prostate cancer in men was established. Epidemiological data, combined with experimental ones, suggest a possible contribution of carcinogens into the increase of the incidence of hormone-dependent tumors. At the same time, mechanisms of action of PAH and cadmium on the development of hormone-dependent tumors are unclear. The accumulated experimental and epidemiological data allow us to conclude that the oncological danger of these carcinogens lies in the combination of genotoxic and hormone-mimetic properties; the main mechanisms, involved in the realization of the effect of BP and cadmium, are associated with changes and disorders at different levels of the structural and functional organization of the organism, including the endocrine system, which can lead to the development of tumors. The urgency of the problem of the incidence of hormone-dependent tumors and the potential role of the studied chemical carcinogens as pollutants of the environment of human functions indicate the need to take these circumstances into account when developing and implementing preventive measures.

Urinary metabolites as indicators of human exposure to chemical carcinogens

Population exposure to environmental chemical carcinogens is a growing public health problem. Carcinogenic chemicals may be classified into two groups: genotoxic and non-genotoxic. A genotoxic chemical has a potential to induce the development of cancer, either in direct interaction with DNA or with cell structures, which are responsible for the maintenance of genome integrity. A non-genotoxic chemical has a potential to induce cancer indirectly by entering the processes of cancer etiopathogenesis. Previous research studies indicate that inorganic arsenic compounds may be associated with various malign diseases (lung cancer, urinary bladder cancer, skin, kidney, liver and prostate cancer). Inorganic arsenic is mainly present in meat, dairy products and grains, while organic arsenic (arsenobetaine) is present in seafood, fruit and vegetables. Benzene metabolites are associated with different types of leukemias and lymphomas, benzidine with bladder cancer, nickel with lung cancer, chromium compounds with lung cancer, nose and nasal sinus cancer. The greatest occupational exposure to benzene is in industry (leather, electronic device, shoes, sports equipment), while people may come into contact with benzidine through consumer goods (leather products, clothes, toys). The highest concentrations of nickel were measured in the beans, walnuts and grains. Cadmium and cadmium compounds cause lung cancer, and influence the occurrence of renal and prostate cancer. The risk of hepatocellular carcinoma is significantly increased in respondents with high concentrations of urinary metabolites of aflatoxin (aflatoxin N7-gvanine adducts). Lindane isomers are present in dairy products, meat, fish, poultry, garden fruit, oils and lipids, leaf and root vegetables and sugar, and they cause non-Hodgkin lymphoma. There is a positive correlation between the consumption of Aristolochia plants and the occurrence of urothelial carcinoma. There are no screening examinations for the identification of persons who are at great risk of developing malign disease in the next 10 or 20 years. As for the prevention of malign diseases, it is necessary to put an accent on finding the adequate methods for determining the concentrations of urinary metabolites for toxic chemical carcinogens and define their risk values.

Structural description of sea turtle fibropapilloma

Fibropapillomatosis is a neoplastic disease that affects sea turtles. It is characterized by multiple papillomas, fibropapillomas and cutaneous and/or visceral fibromas. Although its etiology has not been fully elucidated, it is known that there is a strong involvement of an alpha - herpesvirus, but the influence of other factors such as parasites, genetics, chemical carcinogens, contaminants, immunosuppression and ultraviolet radiation may be important in the disease, being pointed out as one of the main causes of a reduction in the green turtle population. Thus, the objective of this article was to describe the morphology of cutaneous fibropapillomas found in specimens of the green turtle (Chelonia mydas), using light and scanning electron microscopy in order to contribute to the mechanism of tumor formation. Microscopically, it presented hyperplastic stromal proliferation and epidermal proliferation with hyperkeratosis. The bulky mass was coated with keratin, with some keratinocyte invaginations, that allowed the keratin to infiltrate from the epidermis into the dermis, forming large keratinized circular spirals. Another fact that we observed was the influence of the inflammation of the tumors caused by ectoparasites.