Pioneer transcription factors constitute a heterogeneous group of regulatory proteins of animals, which, unlike other transcription factors, are able to recognize and bind target DNA sequences within closed chromatin. This binding can change the local chromatin structure and facilitate binding of other proteins, thus establishing competence for gene expression. The ability to bind silent genes in the closed environment makes the pioneer factors very useful in the processes leading to cardinal alteration of cell phenotype, such as differentiation in embryonic development or cell reprogramming. These proteins can remain bound to target sequences during mitotic division, and due to this probably take part in the maintenance of cellular memory. Apparently, pioneer transcription factors are active participants in carcinogenesis and maintenance of tumor cell phenotype, although their role in these processes needs additional research. It is reasonable to suppose that a further study will help to shed more light on the genetic processes in embryonic development, increase the efficiency of cell reprogramming and also develop new approaches to diagnostics and therapy of cancer diseases.

High mortality from breast cancer is associated with the high heterogeneity of tumor and the frequent recurrences of the pathological process, which are due to the presence of tumor stem cells. The review considers the biological properties of tumor stem cells, the molecular mechanisms of their regulation, interaction with the microenvironment, and their role in the heterogeneity of the morphological and clinical forms of breast cancer.

The colorectal cancer (CC) is one of the most widespread type of cancer all over the world. It is confirmed that the screening procedures intended for timely detection of CC and adenomatous polyps, significantly decrease mortality. The colonoscopy and analysis offeces for occult blood are widely applied as screening procedures. However, they have a number of shortcomings. The studies of the last decade revealed number of genetic and epigenetic markers potentially permitting revealing patients with CC at early stages of development of disease. The article analyzes CC-specific microRNA and their possible interactions with different transcriptional factors. These factors, being integrated into the structure of so called network s with direct signal propagation, ensure special stability of all regulatory system. The derangement of functioning of these networks quite often results in pathological alterations.

The novel ideas of fundamental role of mitochondria in the maintenance of viability of malignant cells have been reviewed. The modern state of research is considered in detail, including: mitochondrial control of the cellular redox state, sites of reactive oxygen species (ROS) production in inner mitochondrial membrane and antioxidant protection systems. Specificities of the structural-functional mitochondrial remodelling in malignant tumors, the mechanisms of the energy metabolism reprogramming, enhancement of the ROS production and adaptation to the hypoxic conditions and metabolic stress are analyzed. The available data including our research on transplanted tumors indicate that cytotoxic action of sodium dichloroacetate (the inhibitor of pyruvate dehydrogenase kinase) depends on biological properties of tumors and intensity of structural-functional mitochondrial rearrangement. Dichloroacetate turned out to be effective for sarcoma 37, but not for Lewis lung carcinoma.

The oxidative status (ROS), markers activation expression (CD69), proliferation activity (Ki67), proapoptotic antigen (CD95) have been investigated on healthy donors and patients with prostatic gland cancer in human blood lymphocytes. The lymphocyte reaction in vitro on γ-irradiation at different doses (0.05-1.0 Gy) has been determined too. It was shown that in these two types of individuals the ROS content does not differ and the reaction on irradiation is not different either. Essential is the difference between the marker expression in lymphocytes of healthy donors and patients with tumour: in individuals with cancer the content of lymphocytes with CD69+ phenotype (in non active situation) and CD95+ increases, the expression of marker Ki67 decreases. The lymphocyte response to irradiation in healthy and tumour lymphocytes is distinguished. Irradiation at doses 0.05-10.0 Gy on tumour patients lymphocytes markers does not influence expression. In healthy donors' lymphocytes the expression of markers is changed considerably, the reaction depends on the marker type: expression of CD69 marker decreases (tendency); expression of Ki67 decreases too; it is unusual that the expression of CD95 changes--it decreases after irradiation at the doses of 0.05-1.0 Gy, then increases with dose. So this work shows the changes in tumour patients' blood lymphocytes in comparison with healthy donors' lymphocytes. The possible mechanisms of the observed phenomenon are discussed.

The quantitative method of determining the level of expression of immunoglobulin light chains on uncompensated data was suggested and used to examine disorders in light chain expression in various B-cell tumors. The average level of expression of the lambda isotype was 4 times higher than the level of expression of kappa isotype. The level of surface and cytoplasmic expression of LC IG varied within wide limits for different people, but there was a high degree of correlation between the levels of expression of kappa and lambda isotypes LC IG as well as between expression of the surface and cytoplasmic forms of each in isotype the same individual. In the majority of B-cell non-Hodgkin's lymphomas correlation between the expression of LC IG on the surface and in the cytoplasm of the cells was diminished. Expression of LC IG in CLL was significantly reduced on the surface of the cells and to a lesser extent--in the cytoplasm. In the case of marginal zone cell lymphoma, LC IG expression level was reduced on the surface of circulating cells and to a lesser extent--in the cytoplasm. In the case of mantle cell lymphoma and DLBCL, expression level of LC IG on the cell surface and in the cytoplasm was the same as in normal B-cells. However, in some cases DLBCL, no LC IG was expressed both on the surface and in the cytoplasm.

One of the hallmarks of cancer is the change of energy metabolism, mainly activation of glycolysis that occurs even at early stages of tumorigenesis. The glycolysis activation can be caused by overexpression of hexokinases, primarily HK1 and HK2. Colorectal cancer, which takes the third place in the cancer morbidity and mortality rates worldwide, is believed to be accompanied with overexpression of HK2, which is .considered a marker of poor prognosis. With the use of the developed CrossHub tool, we performed the analysis of the Cancer Genome Atlas RNA-Sequencing data, which, on the contrary, revealed the prevalence of the down-regulation of HK2 gene and only slight expression alterations in HK1 gene. The Cancer Genome Atlas is the largest resource in the field of molecular oncology that accumulated genomic, transcriptomic and methylomic data for thousands of sample of more than 20 cancers. The transcriptome analysis data for colorectal cancer (283 tumor samples and 41 matched normal samples) were in accord with the results of further qPCR expression level evaluation. Up-regulation of HK1 and HK2 genes was observed only in a part of samples: 12% for HK1 and 30% for HK2. At the same time, the HK2 mRNA level decrease was shown in 50% of cases. Correlation analysis revealed the consistency in HK1 and HK2 expression alterations (Spearman's rank correlation coefficient r(s) = 0.43, p < 0.01), that could be explained by common deregulation mechanisms of these genes in colorectal tumors. The HK3 expression level was significantly increased in 60% of samples. Most likely, just hexokinase 3 contributes significantly to the activation of glycolysis in colorectal cancer.

The transformation of normal precursors into cancer cells is an intricately regulated, multistep process. The master regulatory genes that play a crucial role in the process of organism development may also play a key role in carcinogenesis. From such a point of view, cancer is not simply a genetic disease that is due to a progressive accumulation of mutation--it is also a disorder of the developmental system of the tissue in which cancer emerges. Master regulators and their genes disturb stem cell differentiation upon mutation and thus may serve as targets for cancer therapy, in addition to the classic oncogenes and suppressors of tumor formation. This review is an attempt to give a modern concept of master genes and their functions in adult stem cells of the organism and in carcinogenesis, with pancreatic cancer as an example.

The dogma of the central nervous system (CNS) as an immune-privileged site has been substantially revised in recent years. CNS is an immunocompetent organ and actively interacts with the immune system. Microglia plays a leading role in a CNS immune response. However, in malignant gliomas, there is M2-polarization of microglia acquiring immunosuppressive and tumor-supportive properties. It occurs under the influence of tumor cytokines, such as transforming growth factor-β, interleukin-10, and prostaglandin E2. M2-polarized microglia exhibits reduced phagocytic activity, changes in the expression of many cellular determinants, or inverse of their functions, STAT3 activation, and production of immunosuppressive cytokines that suppress the function of cytotoxic CD8+ T cells or CD4+ T-helper cells type I. Myeloid-derived suppressor cells and regulatory T-lymphocytes, which have been recruited from peripheral blood into tumor tissue, also have immunosuppressive properties. The development of new treatment options for malignant gliomas must consider the role of the microenvironment in maintaining tumor vitality and progression.

Suppression of resistance in acute myeloid leukemia cells to TRAIL-induced apoptosis in multicellular aggregates, was studied using small molecule inhibitors of the activation of the transcription factor NF-kB - NF-k9 Activation Inhibitor IV and JSH-23 at non-toxic concentrations. NF-kB Activation Inhibitor IV and JSH-23 reduced resistance in the acute myeloid leukemia cells in multicellular aggregates to cytotoxic action of recombinant protein izTRAIL. It is shown that the use of these inhibitors decreased the phosphorylation of the RelA (p65) as a main marker activation of the transcription factor NF-kB. We discuss a possible reason for increasing resistance in acute myeloid leukemia cells to TRAIL-induced apoptosis in multicellular aggregates.

Risk factors related to secondary oligomenorrhea (SOM) are the presence of chronic extragenital pathology, abrupt changes in body mass during a short period of time, a burdened perinatal history at the onset of SOM after a year of regular menstruations. Adolescent girls with SOM differ from their healthy peers by a frequent occurrence of hirsutism, obesity and body mass deficit, uterine hypoplasia.

Targeted delivery of semiconductor quantum dots (Q Ds) to tumors overexpressing HER2 cancer marker has been. demonstrated on immunocompromised mice bearing human breast cancer xenografts. To obtain targeted QDs complexes we applied the approach based on the use of protein adaptor system, RNAase barnase and its inhibitor barstar. Specific binding to target cancer marker was achieved through bivalent fusion protein containing two fragments of4D5scFv recombinant antibody and a fragment of barnase. QDs were conjugated to barstar, and final assembly of targeted complexes was obtained through non-covalent specific interaction of barstar, attached to QD, and barnase, that is part of the recombinant targeting protein. The efficient delivery of QDs to HER2-expressing tumor demonstrates the possibilities and prospects of the approach for targeted delivery of nanoparticles to cancer cells in vivo as the way to improve the efficiency of diagnosis and promote development of therapies based on the use of nanoparticles.

The RNA-seq approach for prostate cancer candidate RNA biomarkers screening in plasma and urine obtained by minimally invasive or noninvasive methods is proved to be feasible. Significant amount of RNA biomarkers associated with prostate cancer according to the literature were found in plasma and urine samples obtained from patients with benign prostatic hyperplasia (BPH). The number of detected markers was shown to vary in accordance with method of library preparation used for transcriptome profiling. The detection of known RNA biomarkers for prostate cancer in urine and plasma samples shows the feasibility of such method for minimally invasive diagnostics. The fact of presence of the same RNA biomarkers in samples from patients with BPH suggests their possible lack of specificity and confirms the need for further research in this area.

Hallmark of neuroblastoma is an ability of this malignant tumor to undergo spontaneous regression or differentiation into benign tumor during any stage of the disease, but it is little known about mechanisms of these phenomena. We studied effect of receptor tyrosine kinase receptor KIT on expression of genes, which may be involved in tumor spontaneous regression. Downregulation of KIT expression by RNA interference in SH-SY5Y cells causes suppression of neurotrophin receptor NGFR expression that may promote the loss of sensibility of cells to nerve growth factors, also it causes upregulation of TrkA receptor expression which can stimulate cell differentiation or apoptosis in NGF dependent manner. Furthermore there is an upregulation of genes which stimulate malignant cell detection by immune system, such as genes of major histocompatibility complex HLA class I HLA-B and HLA-C, and interferon-γ receptors IFNGR1 and IFNGR2 genes. Thus KIT can mediate neuroblastoma cell sensibility to neurotrophins and immune system components--two factors directly contributing to spontaneous regression of neuroblastoma.

In this study we evaluated c-kit, VEGFA, and MYC gene expression level in seven neuroblastoma stable cell lines: SK-N-SH, SK-N-BE, SK-N-AS, SH-SY5Y, Kelly, IMR-32, and LAN-1. Expression levels of these genes can serve as diagnostic factors of cancer progression, and proteins encoded by these genes are promising targets for neuroblastoma treatment. SH-SY5Y and SK-N-AS cells have highest MYC expression and the same VEGFA expression, although SH-SY5Y has 10 times higher c-kit expression than SK-N-AS cells. Both IMR-32 and LAN-1 cells have low MYC expression level, but differ in c-kit expression, IMR-32 has significantly higher c-kit expression, than any other neuroblastoma cell line. LAN-1 on the other hand has the highest VEGFA expression. These data suggest that MYC, c-kit, and VEGFA genes can play different roles in development and progression of neuroblastoma depending on other activated molecular mechanisms in malignant cells.

Melanoma is the most lethal malignancy of skin, which is comprised of clinically relevant molecular subsets defined by specific "driver" mutations in BRAF, NRAS, and KIT genes. Recently, the better results in melanoma treatment were obtained with the mutation-specific inhibitors that have been developed for clinical use and target only patients with particular tumor genotypes. The aim of the study was to characterize the spectrum of "driver" mutations in melanoma subtypes from 137 patients with skin melanoma and 14 patients with mucosal melanoma. In total 151 melanoma cases, the frequency of BRAF, NRAS, KIT, PDGFRA, and KRAS mutations was 55.0, 10.6, 4.0, 0.7, and 0.7%, respectively. BRAF mutations were found in 69% of cutaneous melanoma without UV exposure and in 43% of cutaneous melanoma with chronic UV exposure (p=0.045), rarely in acral and mucosal melanomas. Most of melanomas containing BRAF mutations, V600E (92%) and V600K (6.0%) were potentially sensitive to inhibitors vemurafenib and dabrafenib. NRAS mutations were more common in cutaneous melanoma with chronic UV exposure (26.0%), in acral and mucosal melanomas; the dominant mutations being Q61R/K/L (87.5%). KIT mutations were found in cutaneous melanoma with chronic UV exposure (8.7%) and mucosal one (28.6%), but not in acral melanoma. Most of KIT mutations were identified in exon 11; these tumors being sensitive to tyrosine kinase inhibitors. This is the first monitoring of BRAF, NRAS, KIT, PDGFRA, and KRAS hotspot mutations in different subtypes of melanoma for Russian population. On the base of data obtained, one can suppose that at the molecular level melanomas are heterogeneous tumors that should be tested for "driver" mutations in the each case for evaluation of the potential sensitivity to target therapy. The obtained results were used for treatment of melanoma patients.

Several polymorphisms in melanocortin-1 receptor (MC1R) gene are shown to have associations with melanoma risk. In particular, rs1805007, rs1805008, and rs1805009 mutations causing the corresponding R151C, R160W, and D294H changes and associated with the phenotype ("red-hair mutations") are connected with melanoma and non-melanoma skin cancer risks. The work describes the approach to detect these polymorphisms based on primer extension reaction with the following dual bioluminescent assay. Model plasmids with polymorphic MC1R fragments as well as several clinical DNA samples were tested using the developed technique. The results were in good correlation with those obtained by Sanger sequencing.

Acute lymphoblastic leukaemia (ALL) is the most common subtype of childhood cancer. Detection of a specific gene rearrangement allows the identification of prognostically relevant subgroups in childhood B-ALL. There are four common gene rearrangements which are widely studied to see prognostical values (TEL-AML1, BCR-ABL, E2A-PBX1, MLL-AF4) in childhood B-ALL. In this study we show the prevalence of these common gene rearrangements and also explain the way to identify some rare breakpoints which also occur in these gene rearrangements. 97 samples received for diagnosis from paediatric B-ALL patients were included in this study. Qualitative reverse transcriptase PCR was used for detection of the TEL-AML1-t(12;21), E2A-PBX1-t(1;19), BCR-ABL1-t(9;22) and MLL-AF4 t(4;11) fusion transcripts. Unusually sized amplicons were confirmed by FISH and DNA sequencing to confirm atypical breakpoints. Amongst the paediatric B-ALL samples t(12;21), was detected in (∼20%), t(9;22), was detected in (∼8%), t(1;19) was detected in (∼9%) and t(4;11) was detected in 2 cases. t(12;21) with intron 1of the AML1 gene was detected as the most common gene rearrangement in paediatric ALL, whereas one rare form of the TEL-AML1 breakpoint in which TEL is fused with intron 2 of AML1 was also observed. In the t(9;22) breakpoints e13a2, e14a2 and e1a2 were detected as the common breakpoints. Two atypical and rare breakpoint of t(9;22) were detected namely e6a2 and e13a3 in paediatric ALL. TEL-AML1 was found to be the most common translocation in Paediatric B-ALL. Identification of the rare breakpoints through RT-PCR technique requires designing of PCR in such a way that it can detect these rare breakpoints also.

Enhancers make up a huge class of genome regulatory elements that play an important role in the formation and maintenance of specific patterns of gene transcriptional activity in all types of cells. In recent years, high-throughput methods for the genome-wide epigenetic analysis of chromatin have made it possible to identify structural and functional features of enhancers and their role in the spatial and functional organization of the genome and in the formation and maintenance of cell identity, as well as in the pathogenesis of certain diseases. Special attention has been focused on genome regions called super-enhancers, or stretch enhancers, which consist of clusters of elements with properties of classic enhancers. This review considers current data on specific properties of super-enhancers and their role in the formation of interconnected autoregulatory circuits with positive feedback that regulates the most important genes, the activity of which underlies the formation and maintenance of specialized cellular functions.

The article presents the data on the structure and mechanisms of β-catenin functioning. The basic aspects of the role of β-catenin in malignant transformation have been studied at various tumors. Primary structure of β-catenin allows it to interact with many factors and ligands, including transcription factors, α-catenin, cadherin, Axin, Rho family GTPases, Bcl9 et al. This interaction is the base for β-catenin's intracellular multi-functioning. The review presents data on the participation of β-catenin in the mechanisms of adhesion, regulation of RNA metabolism, formation contacts with the cytoskeleton and its role in the canonical Wnt signaling pathway, marked examples pro-inflammatory and anti-inflammatory effects of β-catenin. The β-catenin involvement in malignant transformation and progression of certain tumors is not in doubt. The data on the changes in β-catenin expression in the given examples of colon cancer, prostate cancer, different forms of thyroid cancer and hepatocellular carcinoma are presented with the prospects of its use as a marker and a predictor of malignant transformation. Continued research in this area will not only make use of β-catenin as a potential predictor of malignant tumors, but also to develop approaches to targeted therapy.