Background: Currently coal mining employs over 7 million miners globally. This occupational setting is associated with exposure to dust particles, heavy metals, polycyclic aromatic hydrocarbons and radioactive radon, significantly increasing the risk of lung cancer (LC). The susceptibility for LC is modified by genetic variations in xenobiotic detoxification and DNA repair capacity. The aim of this study was to investigate the association between GSTM1 (deletion), APEX1 (rs1130409), XPD (rs13181) and NBS1 (rs1805794) gene polymorphisms and LC risk in patients who worked in coal mines. Methods: The study included 639 residents of the coal region of Western Siberia (Kemerovo region, Russia): 395 underground miners and 244 healthy men who do not work in industrial enterprises. Genotyping was performed using real-time and allele-specific PCR. Results: The results show that polymorphisms of APEX1 (recessive model: OR_adj = 1.87; CI 95%: 1.01–3.48) and XPD (log additive model: OR_adj = 2.25; CI 95%: 1.59–3.19) genes were associated with increased LC risk. GSTM1 large deletion l was linked with decreased risk of LC formation (OR_adj = 0.59, CI 95%: 0.36–0.98). The multifactor dimensionality reduction method for 3-loci model of gene–gene interactions showed that the GSTM1 (large deletion)—APEX1 (rs1130409)—XPD (rs13181) model was related with a risk of LC development. Conclusions: The results of this study highlight an association between gene polymorphism combinations and LC risks in coal mine workers.

Background. Maintaining radon safety is one of the most critical challenges in modern ecology and genetic toxicology. Radon (222Rn) and its decay daughter products (218Po, 214Po, 214Pb and 214Bi) can interact with biological tissues and induce DNA damage. Because transcribed copies rDNA are necessary for DNA damage repair, we examined whether genomic dosages of active ribosomal genes modulate the genotoxic effects of exposure to high doses of radon. Materials and methods. Chromosome aberration assay in peripheral blood lymphocytes was performed in pupils of the boarding school of Tashtagol (Kemerovo region, Russia) with long-term resident exposure to radon (n = 345) and in childrenof the Kemerovo Region living in radiation-safe conditions (n = 233). The dose of active (transcription-capable) ribosomal gene (AcRG) in the studied groups has been analyzed using Ag-NORS staining regions of chromosomes and cytogenetic semi-quantitative evaluation method. Results. A statistically significant increase in the level of chromosome aberrations in exposure group has been revealed compared with the children of the Kemerovo Region living in radiation-safe conditions (p = 0.00001). It was found that the level of chromosomal abnormalities in Tashtagols children was higher in medium-dose carriers of AcRG compared to owners of a low dose (4.27 0.22% vs. 3.24 0.29%, p = 0.003). Perhaps the low level of chromosomal aberrations in children with low-dose AcRG is associated with an increase in cell death from damaged DNA under genotoxic exposure to radon. Conclusion. The obtained results testify to the significant contribution of the individual characteristics of ribosomal genes in the formation of genotoxic effects of exposure to high doses of radon.

Breast cancer is one of the leading causes of mortality among women. The most frequently encountered tumors are luminal tumors. Associations of polymorphisms in the hOGG1 (rs1052133), APEX1 (rs1130409), XPD (rs13181), SOD2 (rs4880), and CAT (rs1001179) genes were studied in 313 nonsmoking postmenopausal patients with luminal B subtype breast cancer. The control group consisted of 233 healthy nonsmoking postmenopausal women. Statistically significant associations of the XPD and APEX1 gene polymorphisms with the risk of developing luminal B Her2- negative subtype of breast cancer were observed in a log-additive inheritance model, while the CAT gene polymorphism showed an association in a dominant inheritance model (OR = 1.41; CI 95 %: 1.08–1.85; Padj.= 0.011; OR = 1.39; CI 95 %: 1.07–1.81; Padj = 0.013 и OR = 1.70; CI 95 %: 1.19–2.43; Padj = 0.004, respectively). In the group of elderly women (aged 60–74 years), an association of the CAT gene polymorphism with the risk of developing luminal B subtype of breast cancer was found in a log-additive inheritance model (OR = 1.87; 95 % CI: 1.22–2.85; Padj = 0.0024). Using MDR analysis, the most optimal statistically significant 3-locus model of gene-gene interactions in the development of luminal B Her2-negative subtype breast cancer was found. MDR analysis also showed a close interaction and mutual enhancement of effects between the APEX1 and SOD2 loci and the independence of the effects of these loci from the CAT locus in the formation of luminal B subtype breast cancer.

В настоящем исследовании проведена оценка уровня мРНК и белка генов SNCA, DNMT1, а также степени метилирования интрона 1 гена SNCA в CD45+ клетках периферической крови пациентов со спорадической болезнью Паркинсона (БП) и индивидуумов контрольной группы. Впервые было выявлено снижение концентрации белка DNMT1 в CD45+ клетках периферической крови пациентов с БП по сравнению с группой контроля. Обнаружено увеличение уровня мРНК гена DNMT1 у пациентов с БП по сравнению с контролем. Не выявлено статистически значимых различий при сравнении степени метилирования интрона 1 гена SNCA в CD45+ клетках периферической крови пациентов с БП и контроля. В группе контроля выявлена обратная корреляция степени метилирования отдельных CpG островков с концентрацией белка альфа-синуклеина и уровнем мРНК гена SNCA. Проведенное исследование позволяет предположить участие гена DNMT1 в патогенезе БП и отсутствие ассоциации степени метилирования интрона 1 гена SNCA с БП. The aim of this study was to assess the level of mRNA and protein of the SNCA, DNMT1 genes, as well as intron 1 methylation of the SNCA gene in CD45 + peripheral blood cells of patients with sporadic PD and control individuals. For the first time, a decrease in the concentration of DNMT1 protein in CD45 + peripheral blood cells from PD patients compare to controls was revealed. An increase in DNMT1 gene expression in PD patients compare to controls was found. No differences in intron 1 methylation of the SNCA gene in CD45 + peripheral blood cells was found between PD patients and controls. An inverse correlations between methylation level of 21, 22 CpG island in intron1 of SNCA gene and mRNA SNCA gene and alpha-synuclein protein level were found. The study suggests the involvement of DNMT1 in the pathogenesis of PD and the lack of association of PD with intron 1 methylation of the SNCA gene.

Background. Active ribosomal genes and DNA repair genes play an important role in restoring genome integrity. Therefore we were studied relationship of active ribosomal genes dose and DNA repair genes polymorphisms with high level of chromosomal disorders in miners. Materials and methods. The DNA damage level was assessed using chromosomal aberrations (CA) at 288 coal miners and 676 men in the control group. The dose of active ribosomal gene (AcRG) has been analyzed using Ag-NORS staining regions of chromosomes and cytogenetic semi-quantitative evaluation method. Real-time PCR and allele-specific PCR techniques were used to analyze polymorphic variants of the XPG (rs17655), XPD (rs13181), XRCC2 (rs3218536), and XRCC3 (rs861539) genes. Results. A statistically significant (p = 0.0001) increase of the СА level at miners was found in comparison with the control group. The association XPD 2251TG locus with increasing CA level is revealed of in recessive inheritance model (padj = 0.0001). The association XPG 3310GC locus with increasing СА level is revealed at the smoking workers (padj = 0.017). An average dose of AcRG was registered a statistically significant increase in the frequency of single fragments (p = 0.016) at the miners. Conclusion. The obtained data on associations of chromosomal aberrations with different variants of DNA repair genes and the dose of active ribosomal genes are useful for the formation of high-risk groups.