Malignant gliomas, aggressive and highly invasive tumors with a great number of genetic and epigenetic alterations in genes involved in the cell cycle regulation, the apoptotic pathways, cell invasion ability, and angiogenesis, are considered to be among the deadliest of human cancers. The role of epigenetic mechanisms in the pathogenesis of malignant transformation despite recent progress is not yet clear elucidated and remains under intensive study. This review describes the mechanisms of epigenetic regulation of gene expression, including post-translational modification of histones, DNA methylation in the promoter regions, and microRNA regulation. The genetic and epigenetic factors driving the pathogenesis of gliomas in their possible mutual influence and the potential epigenetic targets that can be used in the development of diagnostics and new therapeutic approaches are also discussed.

When the adaptive response (AR) was studied on human blood lymphocytes, a new dependence was discovered. This dependence defines the direction of the radiosensitivity change after a low dose of irradiation. Using micronucleus (MN) test with cytochalasin B the dependence between the cell reaction after low level irradiation and radiosensititvity (the effect after irradiation at the dose of 1 Gy) was observed. The negative correlation between the frequency of AR manifestation, sensibilization, intermediate links and radiosensitivity was discovered. This regularity is observed in the population of Moscow, Obninsk, Chelyabinsk region (irradiated and control) inhabitants, Chernobyl accident liquidators, Moscow children, in individuals with Hodgkin's lymphoma before and during treatment. The negative correlation is also noted by AR determination with two irradiation schemes: in one or two different cell cycle phases (G1-G1 or G1-G2). Similar links are observed using the chromosome methaphase analysis (the frequency of cells with chromosome aberrations). So, the results of the experiments conducted allow us to suppose that the connection between the cell radiosensitivity and a different type of reaction after low dose irradiation--from AR to the increase in radiosensitivity (sensibilization) is a general regularity. AR is induced by low level irradiation and high cell radiosensitivity, while sensibilization is induced by low radiosensitivity. Since AR and sensibilization can be induced not only by irradiation, but many different chemicals and physical agents, the described correlation can be observed in the case of different exposures. Cellular AR and sensibilization are integral indexes depending on many genetic and epigenetic factors, as well as on the initiation of a large number of events. However, the discovered mechanisms of interrelations are still difficult to explain.

The objective of this study was to investigate in vivo the dose response of radiation induced chromosomal aberrations in human blood lymphocytes of lung cancer patients given non-uniform fractional exposures to high doses of therapeutic 60Co gamma-rays delivered synchronously with polychemotherapy. The chromosome aberration analysis was carried out in peripheral blood lymphocytes of 13 lung cancer patients who manifested II to IV developmental clinical stage. During the course of radiotherapy they received the accumulated tumor dose ranged 47.5 to 70 Gy. The yield ofdicentrics, centric rings and fragments was measured in the blood samples taken before treatment, after the first day and after the complete course of radiotherapy. Based on cytogenetic measurements of 3 patients, the average tumor dose after the first day was estimated to be 2.1 to 3.0 Gy given that the corresponding physical dose was (1.0 Gy + 1.5 Gy). The quotient of the individual dose estimated by the frequency of aberrations to the physical dose after the complete course of radiotherapy was calculated for all 13 patients. The mean quotient was shown to be equal to 93 +/- 9% ranged 50 to 154%.

The CD38 gene codes a membrane protein which takes part in cell adhesion and catalyzes the formation of cyclic ADP-ribose. Using RT-PCR method we tested the presence of full-size and alternative forms of mRNA CD38 in samples of tumor tissue of patients with colorectal cancer and in tumor cell lines. It was shown that there are the cells in the tumor tissue which expressed CD38 gene. In tumor tissue of patients the alternative form of mRNA CD38 was detected less frequently than full-size form. Cells of lines Colo-205, T-84, HCT15 and HCT116 contained mRNA CD38, in cells of lines Caco-2 and SW-620 mRNA CD38 was absent. In cells of tumor tissue on the first stage of colorectal cancer CD38 gene was expressed in 100% of cases. On the second, third and fourth stages of the disease gene expression was observed less often. The frequency of mRNA CD38 detection not depend on tumor localization, tumor grade and presence of metastases. Using method of restriction analysis CpG methylation was detected in binding sites of transcription factor Sp1 and receptor of retinoic acid (RARE) in all tested samples of tumor tissue independently of the presence or absence of mRNA CD38. The obtained data suggest that in the tumor cells of patients with colorectal cancer the expression of the CD38 gene is heterogeneous.

To date, there are more than two thousand human miRNAs, each of them may be involved in the regulation of hundreds of protein coding target genes. Methylation of CpG-islands, in turn, affects miRNAs gene expression. Our aim was to evaluate the role of methylation in the regulation of miRNA gene expression and, consequently, in the regulation of expression of target genes in primary lung tumors. Using a common collection of non-small cell lung cancer samples we performed a comprehensive study, including analysis of the methylation status and expression levels of some miRNA genes and their potential target genes on chromosome 3: RAR-beta2 and NKIRAS1. Increased frequency of methylation in lung tumors compared to histologically normal tissue was revealed for miR-9-1 and miR-34b/c genes with significant statistics (P < or = 0.05 by Fisher exact test) and for miR-9-3 and miR-193a was marginally significant (P < or = 0.1). Significant correlation was revealed between alterations of methylation and expression level of miR-9-1 gene (P = 5 x 10(-12) by Spearman) in the lung tumors, this suggests the role of methylation in the regulation of expression of this miRNA genes. Besides, a statistically significant negative correlation (P = 3 x 10(-12)-5 x 10(-13) by Spearman) was found between alterations of expression levels of miR-9-1 and miR-17and RAR-beta2 target gene and also between expression level alterations of miR-17 and NKIRAS1 that was not previously analyzed. The inverse relationship between expression levels of miRNA genes and their target genes is consistent with the known mechanism of suppression of protein coding genes expression under the action of miRNAs. For the first time significant correlations (P = 3 x 10(-10)-4 x 10(-13) by Spearman) were shown between alterations of methylation status of miRNA genes (miR-9-1, miR-9-3, miR-34b/c, miR-193a) and the expression level of RAR-beta2 target gene and between alterations of methylation status of miR-34b/c, and miR-193a and the expression level of NKIRAS1 target gene in the primary lung tumors, which suggests the possibility of indirect effects of methylation of miRNA genes on expression level of target genes.

Recent studies have suggested that mRNAs transcribed from cancer/testis genes might be used as biomarkers of cancer cells migrating through the bloodstream. Using RT-PCR we evaluated the expression of several cancer/testis mRNAs (MAGEA1-6, GAGE1-8, NY-ESO-1, SSX1, 2, and 4, XAGE1 and MAGEC1) in primary tumors and peripheral blood samples of colorectal cancer patients. The detection rate of at least one of the transcripts was 95% (37/39 samples) for primary tumors and 81% (52/64 samples) for the peripheral blood. Moreover, selected mRNAs were detectable in cellular fraction of the peripheral blood at all stages the disease (14 out of 14 cases), whereas in extracellular fraction of plasma were found only at stages III and IV. Obtained data open a possibility of early diagnosis of colorectal cancer in people at high risk by peripheral blood analysis.

Lytic viral infection results in production of viral progeny, and lysis of the infected cells. Tumor cells are usually more sensitive to virus infection. Studies of viral oncolysis indicate that it could represent a promising alternative approach to cancer therapy. The ability of viruses to kill selectively cancer cells had been noticed for quite a long time ago. However, only in recent years, based on deeper understanding of molecular biology of viruses and the cell and due to the development of modern methods for directed modification of viruses, there emerged a real opportunity for development of virus variants with improved therapeutic potential. Adenoviruses represent one of the most studied models of oncolytic viruses. The DNA-containing viruses are very suitable for genetic manipulation and show minimal pathogenicity. The review summarizes data on directions and approaches aiming generation of highly efficient variants of oncolytic adenoviruses. The approaches include introduction of directed genetic modifications into viral genome, accelerated selection of oncolytic viral variants following treatment with mutagens, the use of adenoviruses as vectors for introduction of therapeutic gene products, optimization of viral delivery systems, minimalization of negative effects from the host immune system etc. The dynamic development of studies in the field holds promise for introduction into clinical practice of many variants of oncolytic adenoviruses in the very near future.

Review is devoted to detailed consideration of the functioning in normal and immortal cells of one of the main chromosomal regions, telomeres, being dynamic nucleoprotein structures that cap the ends of eukaryotic chromosomes, protecting them from degradation and end-to-end fusion. The role of telomeres in maintenance of genome stability and cell division was also analyzed. Telomere function depends on many interrelated parameters such as telomerase activity, status of the telomere safety complex shelterin and telomere associated proteins (factors of replication, recombination, and reparation of DNA breaks, and so on). We have focused on mechanisms of telomere length control in normal and immortal cells as well as in cells containing active telomerase and cells wherein it is absent. We have analyzed the features attributed to alternative telomere lengthening, namely in view of recently discovered additional mechanism of telomere shortening by trimming of t-cycles. We have viewed a possibility of expression in normal mammalian cells of both telomerase dependent and recombinational ways of telomere length control and the role of shelterin proteins in choice of the one of them as the dominant way. The role oftelomeres in spatial organization of nucleus, in mitosis and meiosis has been also considered. Diversity of telomere organization in mammalians including unusual telomeres in Iberian shrews has been discussed.

We studied the expression of genes encoding vascular endothelial growth factors VEGF-A, VEGF-C, VEGF-D and their receptors in cell cultures of human multiple myeloma IM9, RPMI 1640, RPMI 8226. The studied cells did not differ by the expression of growth factors. Expression of VEGFR1 receptor was detected only in IM9 cells and VEGFR2 and VEGFR3 receptors were not expressed in multiple myeloma cells. A dependence between the aberrant CD45/CD56 phenotype of human multiple myeloma cells and VEGFR1 expression in them was revealed. The only VEGFR1-positive IM9 cell culture was most resistant to Velcade (bortezomib).

We studied the expression of peroxiredoxin genes (PRDX1, PRDX2, PRDX3, and PRDX6) in human erythroleukemia K652, human breast carcinoma MCF-7, and human ovarian carcinoma SKOV-3 cells during cisplatin resistance development. It was found that drug resistance formation was accompanied by a significant increase in the expression of PRDX1, PRDX2, PRDX3, PRDX6 genes in all cancer cell strains, which confirms the important contribution of redox-dependent mechanisms into the development of cisplatin resistance of cancer cells.

We studied the content of tissue inhibitors of matrix metalloproteinases 1 and 2 (TIMP-1 and TIMP-2) and activities of matrix metalloproteinases (MMP) in the serum and lungs of mice with Lewis lung carcinoma metastasizing into the lung. Metastasizing was associated with increased serum content of TIMP-1 and TIMP-2 (only on day 20 at the terminal stage of the tumor process). These data confirm the hypothesis on pro-tumorigenic role of TIMP-1 in the serum. Locally, the development of metastases was associated with a decrease in TIPM-1 concentration (day 7), an increase in TIMP-2 concentration (days 7 and 20), and elevated activity of MMP at all terms of the study (days 7, 15, and 20). Increased concentration of TIMP-2 in the lungs (but not in the serum) can be regarded as an indicator of Lewis lung carcinoma metastasizing.

Association study of 6 candidate single-nucleotide polymorphisms (rs7921, rs7956547, rs3761243, rs11737764, rs6599400, rs1690916) was carried out in a group of patients with bone tumors of different histological structure (n=68) and control group of normal subjects (n=96). Significant associations of rs6599400 and rs1690916 polymorphisms with disease risk were detected (odds ratio 2.15 [1.06-4.24] and 0.39 [0.19-0.78], respectively). These polymorphisms were located in untranslated genome regions: polymorphism rs6599400 in the 5' region of fibroblast growth factor-3 receptor gene (FGFR3), rs1690916 in the 3' region of mouse MDM2 p53-binding protein homolog (MDM2). These data indicated a possible role of hereditary genetic factors in the formation of predisposition to bone sarcomas and confirmed previous findings according to which these genes should be regarded among the most probable factors involved in tumor development, including tumors of the bone and cartilage tissues.

The b-cell chronic lymphatic leukemia is the most common among all lymphatic proliferative diseases and is characterized by significant variability of its clinical course. The mutation status of genes of variable region of heavy chains of immunoglobulins (IgVH) is the most reliable prognostic factor forecasting time until beginning of treatment in case of b-cell chronic lymphatic leukemia. However its detection nowadays is inaccessible for routine diagnostics. Among surrogate markers of mutation status the indicator of expression of ZAP-70 by tumor cells estimated using flow cytofluorometry. However, in publications there are different guidelines concerning the technique of mentioned marker. To establish the optimal approach to evaluation of expression of ZAP-70 the peripheral blood samples of 5I patients with b-cell chronic lymphatic leukemia and 10 healthy persons were analyzed. The comparison with the results of detection of mutation status of IgVH-genes revealed the advantage of applying the technique of calculation of MFI ratio during interpretation of data of expression of ZAP-70 obtained with flow cytofluorometry. In this framework, the indicator of expression of ZAP-70 can be applied in assessing the course of disease and time until the beginning of treatment of b-cell chronic lymphatic leukemia.

Blocks of preparations from 22 patients with metastatic renal cell carcinoma on target therapy were studied. The patients were examined for mutations/methylation of VHL gene. The mutations were detected in 10 (45.5%) of 22 patients, VHL methylation was found in 1 (4.5%) patient. Overall survival was 36.4 and 66.7% in the groups of patients with and without gene VHL alteration, respectively. Progression-free survival was 47.6 and 57.1%, respectively (p = 0.619), relapse-free survival--63.6 and 45.5%, respectively (p = 0.682), progression was registered in 36.4 and 54.5%, respectively (p = 0.682). Gene VHL inactivation had no effect on prognosis of the disease and results of anti-angiogenic therapy.

Kinase TOR (target of rapamycin), discovered as a target of antibiotic rapamycin, the evolutionarily conservative serine/threonine kinase that integrates numerous extra-cellular and intracellular signals, regulating cell growth, protein synthesis and metabolism. Mammalian kinase (mTOR) exists in two complexes: the rapamycin-sensitive TORC1 and rapamycin resistant mTORC2, controlling in the cell different programs. Identification of mTOR as integral component PI3/Akt way that deregulated during carcinogenesis, as well as the existence of a cross-talk between the tumor-suppressor p53 cascade and mTOR demonstrates its unique role in the process of neoplastic growth. This review discusses the various aspects of the regulation of the kinase mTOR, the relationship with the general cell-signaling pathways and its use as a target for the cancer, diabetes, obesity, neurodegenerative changes and hereditary syndromes of aging.

The paper considers the current aspects of the morphology, immunohistochemistry, molecular biology of gastrointestinal stromal tumors (GIST). It describes the major signs of different histological types of GIST, which depend on the morphological, immunohistochemical types of interstitial cells of Cajal. Problems in the primary diagnosis and prognosis of GIST are discussed.

The value of molecular genetic methods in the current diagnosis of lymphoproliferative diseases is estimated. A standardized BIOMED2 protocol for these studies is described. The merits and demerits of this method are considered.

Human genome variability observed within patient cohorts is considered as a goal of functional genomics essential for personalized medicine progress. In the current research we implement functional analysis of 31 polymorphic Alu insertions located within gene introns for individual genomes of patients with acute lymphoblastic leukemia (ALL). As a result we demonstrated a decrease of the primary transcripts content for 21 Alu-containing alleles. The most strong inhibitory effect of 10 Alu insertions was observed in both mononuclear blood cells of healthy donors and B-lymphoblasts of ALL patients. Allele frequencies of three Alu insertions that are located in MEF2C (two of them) and TAX1BP1 genes significantly differ (p-value 0.027. 0.052. 0.014 accordingly) between cohorts of healthy donors and ALL patients. Prolong influence of the Alu insertions on intracellular content of mature mRNA was studied for corresponding allele of TARBP1 gene.

To study the pattern of complex chromosome damages (CCD) in acute leukemias (AL) and their place in the development of post-transplant recurrences (PTR) of AL.

Polymorphism ofglutathione-S-transferase (GSTA1, GSTM1, GSTM3, GSTP1, and GSTT1) and DNA repair (ERCC1, ERCC2, and XRCC1) genes in samples of ovarian cancer patients and healthy women of the Russian ethnic group was studied. A trend in the allele frequency variation of ERCC2 gene single nucleotide polymorphism (rs13181, A > C) was revealed. The A allele frequency was higher in the sample of patients (60,6% versus 52,9%, P = 0.058).