Search

Abstract The paper presents a one-dimensional gas-dynamic model that gives an opportunity to establish the necessary conditions for the emergence and determine characteristics of a stationary flow of a compressible continuous medium with nonlinear thermal conductivity, an example of which is a fully or partially ionized plasma, in the presence of a localized heat source with a given power.

Aim: to reveal hereditary mutations in patients with adenomatous polyps of the gastrointestinal tract. Patients and methods: a retrospective cohort study included 8 patients with adenomatous polyps of the gastrointestinal tract (ranging from 4 to several hundred). The APC, AXIN2, BMPR1A, BRCA2, CDH1, CHEK2, EPCAM, GALNT12, GREM1, MLH1, MLH3, MSH2, MSH3, MSH6, MutYH, NTHL1, PMS2, POLD1, POLE, SMAD4, STK11 genes were studied using new generation sequencing. Results: five patients were found to have pathogenic mutations in the genes APC (3 patients with > 100 polyps), POLE (1 patient with < 10 polyps), MutYH (1 patient with 2 mutations with > 28 polyps; 1 patient with monoallelic mutation in combination with a mutation in the APC gene with a number of polyps > 100). Conclusion: the probability of detecting a pathogenic mutation increases with an increase in the number of polyps in a patient.

Background: More than 500 thousand new cases of malignant neoplasms are registered annually in the Russian Federation, of which more than 50 thousand new cases are due to hereditary forms. Improving the diagnosis of these diseases will make it possible to detect tumors at the early stages and take timely preventive and therapeutic measures. Aims: Creation of a database and development of a software for the NGS data analysis for the prevention and early diagnosis of hereditary forms of oncological diseases. Methods: The present study used 636 DNA samples obtained from cancer patients with a high hereditary risk or a burdened family history. DNA was isolated from blood lymphocytes. DNA libraries were prepared with a KAPA Target Enrichment Panel (Roche). The panel included probes for targeted enrichment of the coding region of 44 genes. NGS was performed on the MiSeq platform (Illumina). Results: We identified 65 pathogenic/ probably pathogenic nucleotide sequence variants in 96 patients in the ATM, BLM, BRCA1, BRCA2, CHEK2, EPCAM, MEN1, MLH1, MSH2, MSH3, MSH6, MUTYH, PALB2, TP53 genes. We also identified 2858 nucleotide sequence variants of unknown clinical significance. Conclusions: We have created a local database that contains both genetic variants and clinical and anamnestic data. The database contains 4763 nucleotide sequence variants at the moment, among which 2522 are unique variants identified in a single patient.

Objective The problem of drug resistance to BRAF-targeted therapy often occurs in melanoma treatment. Activation of PI3K/AKT/mTOR signaling pathway is one of the mechanisms of acquired resistance and a potential target for treatment. In the current research, we investigated that dual inhibition of mTOR and MEK synergistically reduced the viability of melanoma cells in vitro. Methods A combination of rapamycin (a macrolide immunosuppressant, mTOR inhibitor) and binimetinib (an anti-cancer small molecule, selective inhibitor of MEK) was studied using a panel of melanoma cell lines, including patient-derived cells. Results It was found, that combinatorial therapy of rapamycin (250 nM) and binimetinib (2 μM) resulted in 25% of cell viability compared to either rapamycin (85%) or binimetinib alone (50%) for A375 and vemurafenib-resistant Mel IL/R cells. The suppressed activation of mTOR and MEK by combined rapamycin and binimetinib treatment was confirmed using Western blot assay. Cell death occured via the apoptosis pathway; however, the combination treatment significantly increased the apoptosis only for Mel IL/R cells. The enhanced cytotoxic effect was also associated with enhanced cell cycle arrest in the G0/G1 phase. Conclusion In general, we provide the evidence that dual inhibition of mTOR and MEK could be promising for further preclinical investigations.

We consider the possibility of sustaining a discharge in xenon efficiently emitting light in a wavelength range of 11.2 nm ± 1% by a subnanosecond terahertz radiation pulse. We have simulated such a discharge for parameters typical of experiments using modern free-electron lasers as a source of a high-intensity terahertz radiation. It is shown that a NovoFEL-3 modernized free-electron laser at the Budker Institute will allow to sustain a point-like plasma discharge with a density of excited Xe10+–Xe11+ ions sufficient for the yield of extreme ultraviolet radiation with an average power of 35 W in a wavelength range of 11.2 nm ± 1%.

Intratumoral heterogeneity and clonal variability are among the central problems of clinical oncology, leading to resistance to therapy, relapse, and metastasis. High-throughput sequencing of the tumor exome makes it possible to investigate the subclonal tumor organization. Target panel, clinical exome, and complete exome sequencing data were compared in tumors with different mutational burden, acute myeloid leukemia (AML) in children and acral melanoma. Targeted sequencing of AML samples detected more than one potential driver mutation in the signaling pathway genes KIT, NRAS, KRAS, CBL, and FLT3 in one patient, reflecting the complex clonal structure of the tumor substrate. Clusters of mutant alleles corresponding to different populations of leukemic cells in a sample were isolated based on exome sequencing data from the same AML patients. A comparison of the mutation profile for a primary AML sample and samples obtained in remission and relapse made it possible to trace the dynamic changes in the clonal composition of the tumor. The subclonal tumor structure was investigated in an acral melanoma case as an example. Mutant alleles present in the sample with close frequencies were clustered using the SciClone and ClonEvol packages. The results were used to predict the intratumoral clonal composition and to assume a clonal evolution model, which described the changes in the clonal composition of the tumor during metastasis, including the appearance of new mutations that might be associated with further disease progression. The approach used in the work is suitable for identifying the mutations that cause the formation of new tumor clones, which may have a proliferative advantage, in particular, in conditions of antitumor therapy.

Molecular profiling of tumors may provide promising options for personalized treatment. We have examined the spectrum of germline and somatic mutations in 23 breast cancers (ВС) of various molecular subtypes, including tumors 1) with expression of estrogen, progesterone and/or epidermal growth factor receptor HER2/neu, and 2) with a triple negative phenotype. Genomic DNA specimens were isolated from archived tumor and normal tissue samples and subjected to targeted sequencing of the coding regions of 25 cancer-associated genes with a mean coverage of x 1000. In the triple negative subtype of ВС, the pathogenic germline mutations BRCA1 c.66_67delAG (185delAG) and BRCA1 c.3226_3227AG (3347delAG) were detected, while the germline mutation BRCA2 658_659del (886delGT) was found in patients with positive receptor staining. Mutations in BRCAl/2 were overrepresented by frequency (80%), pointing at common loss of heterozygosity affecting the normal allele. Somatic mutations in the TP53 gene were found in 7/10 (70%) patients with the triple negative subtype of ВС and in 3/13 (23%) in the group with positive receptor staining. Additionally, in both groups of patients, somatic mutations of the PTEN, MSH2, MSH6, and MUTYH genes were detected.

Introduction. Skin melanoma in children is a very rare disease that differs in many aspects from skin melanoma in adults. The conventional criteria for clinical diagnostics of melanoma observed in adults are often absent in children and adolescents, making it difficult to make a diagnosis on time.Objective. The aim of the study is to assess the clinical significance of various diagnostic criteria in the analysis of a rare case of congenital pigment skin neoplasm in a child.Materials and methods. The clinical case of a congenital melanocytic lesion in a wrist joint area in a girl 5 months old.During the primary diagnosis, an ultrasound examination was carried out. The tumor excision was performed with replacement of defect using moved skin flap. Histological, genetic and cytogenetic (fluorescent hybridization in situ, FISH) examination of a tumor sample was carried out.Results. The histological examination revealed areas of cellular atypia with high mitotic activity and the presence of pathological mitoses. According to FISH results, an increase in the copy of the RREB1 gene was observed in the sample, which may indicate amplification of this chromosome region. Genetic testing revealed a Q61K mutation in the NRAS gene.Conclusion. Despite the presence of histological features of neoplasm malignancy and ambiguous FISH results, the described case should be considered as congenital nevus with atypical proliferative nodes based on combination of clinical data (early age at the time of surgery, expansive growth pattern, multiplicity of nodes, lack of necrosis, long relapse-free period).

SARS-CoV-2 has spread rapidly across the globe, with most nations failing to prevent or substantially delay its introduction. While many countries have imposed some limitations on trans-border passenger traffic, the effect of these measures on the spread of COVID-19 strains remains unclear. Here, we report an analysis of whole-genome sequencing of 3206 SARS-CoV-2 samples from 78 regions of Russia covering the period between March and November 2020. We describe recurring imports of multiple COVID-19 strains throughout this period, giving rise to 457 uniquely Russian transmission lineages, as well as repeated cross-border transmissions of local circulating variants out of Russia.

We propose a simple model of quasi-one-dimensional steady-state nonequilibrium plasma flow propagating along the axis of an open magnetic trap and sustained by an rf electromagnetic field. The model makes it possible to analyze qualitatively possible regimes of the plasma flow in the presence of induced intrinsic rf field amplified due to geometrical resonance with the plasma flow and to determine the main features and key characteristics of nonlinear absorption of the external field energy.

Acral melanoma is one of the most aggressive and fast-growing forms of cutaneous melanoma and is characterized by a predominant location on the palms and feet. Primary tumors, metastases, and normal tissue samples from five acral melanoma patients were examined by massive parallel sequencing, focusing on the coding regions of 4100 genes involved in the origin and progression of hereditary and oncology diseases. Somatic mutations were found in genes related to cell division, proliferation, and apoptosis (BRAF, NRAS, VAV1, GATA1, and GCM2); cell adhesion (CTNND2 and ITGB4); angiogenesis (VEGFA); and the regulation of energy metabolism (BCS1L). Comparisons of target DNA sequences between morphologically normal and primary tumor tissues and between normal and metastatic tissues identified the candidate genes responsible for rapid metastasis in acral melanoma.

Background A giant congenital melanocytic nevus (GCMN) is found in 0.1% of live-born infants. If present, the lesion has a chance of about 6% to develop into malignant melanoma. Both children and adults can be affected by malignant melanoma arising in a giant congenital nevus. Up to 95% of GCMNs harbor NRAS mutations, and mutations in the BRAF, MC1R, TP53, and GNAQ genes have also been described. The individualization of therapy is required, but diagnostic and prognostic criteria remain controversial. Case presentations We report two cases: 1) melanoma arising in a giant congenital nevus during the first month of life complicated with neurocutaneous melanosis (NCM), and 2) melanoma arising in a giant congenital nevus during the first 6 months of life. Pathology, immunohistochemistry, and genetic analyses of tumor tissue were performed. The first case revealed only a non-pathogenic P72R polymorphism of the TP53 gene in the homozygote condition. For the second case, a Q61K mutation was detected in the NRAS gene. Conclusion Malignant melanoma associated with GCMN is rare and therefore poorly understood. Outcomes have been linked to the stage at diagnosis, but no additional pathological prognostic factors have been identified. The most frequent genetic event in giant CMNs is NRAS mutations, which was discovered in one of our cases. To accumulate evidence to improve disease prognosis and outcomes, children with congenital melanocytic nevus should be included in a systemic follow-up study from birth.

Intratumoral heterogeneity and clonal variability are among the central problems of clinical oncology, leading to resistance to therapy, relapse, and metastasis. High-throughput sequencing of the tumor exome makes it possible to investigate the subclonal tumor organization. Target panel, clinical exome, and complete exome sequencing data were compared in tumors with different mutational burden, acute myeloid leukemia (AML) in children and acral melanoma. Targeted sequencing of AML samples detected more than one potential driver mutation in the signaling pathway genes KIT, NRAS, KRAS, CBL, and FLT3 in one patient, reflecting the complex clonal structure of the tumor substrate. Clusters of mutant alleles corresponding to different populations of leukemic cells in a sample were isolated based on exome sequencing data from the same AML patients. A comparison of the mutation profile for a primary AML sample and samples obtained in remission and relapse made it possible to trace the dynamic changes in the clonal composition of the tumor. The subclonal tumor structure was investigated in an acral melanoma case as an example. Mutant alleles present in the sample with close frequencies were clustered using the SciClone and ClonEvol packages. The results were used to predict the intratumoral clonal composition and to assume a clonal evolution model, which described the changes in the clonal composition of the tumor during metastasis, including the appearance of new mutations that might be associated with further disease progression. The approach used in the work is suitable for identifying the mutations that cause the formation of new tumor clones, which may have a proliferative advantage, in particular, in conditions of antitumor therapy.

Molecular profiling of tumors may provide promising options for personalized treatment. We have examined the spectrum of germline and somatic mutations in 23 breast cancers (ВС) of various molecular subtypes, including tumors 1) with expression of estrogen, progesterone and/or epidermal growth factor receptor HER2/neu, and 2) with a triple negative phenotype. Genomic DNA specimens were isolated from archived tumor and normal tissue samples and subjected to targeted sequencing of the coding regions of 25 cancer-associated genes with a mean coverage of x 1000. In the triple negative subtype of ВС, the pathogenic germline mutations BRCA1 c.66_67delAG (185delAG) and BRCA1 c.3226_3227AG (3347delAG) were detected, while the germline mutation BRCA2 658_659del (886delGT) was found in patients with positive receptor staining. Mutations in BRCAl/2 were overrepresented by frequency (80%), pointing at common loss of heterozygosity affecting the normal allele. Somatic mutations in the TP53 gene were found in 7/10 (70%) patients with the triple negative subtype of ВС and in 3/13 (23%) in the group with positive receptor staining. Additionally, in both groups of patients, somatic mutations of the PTEN, MSH2, MSH6, and MUTYH genes were detected.

Background: Circulating tumor DNA (ctDNA) holds great potential for cancer therapy and can provide diagnostic and prognostic information before and during treatment. Methods: Plasma DNA samples from 97 melanoma patients, 20 healthy donors and 3 patients with benign skin tumors were analyzed by microarray analysis and droplet digital PCR (ddPCR). Results: A microarray for simultaneous detection of six BRAF V600 mutations in ctDNA has been developed. The method allows the detection of 0.05% mutated DNA from WT DNA background. For paired samples (pre-surgery plasma and tumor tissue) isolated from 74 patients, the concordance of genotypes between tumor DNA and ctDNA was 65% (48/74). BRAF mutations in ctDNA were detected in 27/50 patients with BRAF-positive tumors and in 3/24 patients with BRAF wild-type tumors. The presence of ctDNA BRAF mutations in 23 plasma samples from melanoma patients undergoing therapy correlated significantly with tumor progression (P=0.005). The increase in cell-free DNA levels measured by ddPCR also correlated with disease progression (P=0.02). The concordance of results obtained by microarray identification of BRAF mutations and those obtained by ddPCR was 91%. Conclusion: The novel microarray-based approach can be a useful non-invasive tool for accurate identification of ctDNA BRAF mutations to monitor disease progression.

Next generation sequencing (NGS) technologies have greatly enhanced our ability to identify new viral pathogens in various types of biological samples. This approach has led to the discovery of new viruses and has revealed hidden associations of viromes with many diseases. However, unlike the 16S rRNA, which allows for bacterial detection by metabarcoding, the diversity and variability of viral genomes render the creation of universal oligonucleotides for targeting all known and novel viruses impossible. While whole­genome sequencing solves this problem, its efficiency is inadequate due to the high cost per sample and relatively low sensitivity. Furthermore, the existing approaches to designing oligonucleotides for targeted PCR enrichment are usually incomprehensive, being oriented at detecting a particular viral species or a genus based on the presumption of its presence in the sample. In this study, we developed a computational pipeline for designing genus-specific oligonucleotides that would simultaneously cover a multitude of known viruses from different taxonomic groups. This new tool was used to design an oligonucleotide panel for targeted enrichment of viral nucleic acids in different types of samples, and its applicability for the detection of multiple viral genera at once was demonstrated. Next, we created a custom protocol for NGS library preparation adapted to the new primer panel, which was tested together on a number of samples and proved highly efficient in pathogen detection and identification. Since a reliable algorithm for bioinformatic analysis is crucial for rapid classification of the sequences, in this work, we developed an NGS­based data analysis module and demonstrated its functionality both for detecting novel viruses and analyzing virome diversity. This work was supported by an RSF (Russian Science Foundation) grant (No. 17-74-20096).

Viruses are evolving at an alarming rate, spreading and inconspicuously adapting to cutting-edge therapies. Therefore, the search for rapid, informative and reliable diagnostic methods is becoming urgent as ever. Conventional clinical tests (PCR, serology, etc.) are being continually optimized, yet provide very limited data. Could high throughput sequencing (HTS) become the future gold standard in molecular diagnostics of viral infections? Compared to conventional clinical tests, HTS is universal and more precise at profiling pathogens. Nevertheless, it has not yet been widely accepted as a diagnostic tool, owing primarily to its high cost and the complexity of sample preparation and data analysis. Those obstacles must be tackled to integrate HTS into daily clinical practice. For this, three objectives are to be achieved: (1) designing and assessing universal protocols for library preparation, (2) assembling purpose-specific pipelines, and (3) building computational infrastructure to suit the needs and financial abilities of modern healthcare centers. Data harvested with HTS could not only augment diagnostics and help to choose the correct therapy, but also facilitate research in epidemiology, genetics and virology. This information, in turn, could significantly aid clinicians in battling viral infections.

Background Carotid body tumor (CBT) is a form of head and neck paragangliomas (HNPGLs) arising at the bifurcation of carotid arteries. Paragangliomas are commonly associated with germline and somatic mutations involving at least one of more than thirty causative genes. However, the specific functionality of a number of these genes involved in the formation of paragangliomas has not yet been fully investigated. Methods Exome library preparation was carried out using Nextera® Rapid Capture Exome Kit (Illumina, USA). Sequencing was performed on NextSeq 500 System (Illumina). Results Exome analysis of 52 CBTs revealed potential driver mutations (PDMs) in 21 genes: ARNT, BAP1, BRAF, BRCA1, BRCA2, CDKN2A, CSDE1, FGFR3, IDH1, KIF1B, KMT2D, MEN1, RET, SDHA, SDHB, SDHC, SDHD, SETD2, TP53BP1, TP53BP2, and TP53I13. In many samples, more than one PDM was identified. There are also 41% of samples in which we did not identify any PDM; in these cases, the formation of CBT was probably caused by the cumulative effect of several not highly pathogenic mutations. Estimation of average mutation load demonstrated 6–8 mutations per megabase (Mb). Genes with the highest mutation rate were identified. Conclusions Exome analysis of 52 CBTs for the first time revealed the average mutation load for these tumors and also identified potential driver mutations as well as their frequencies and co-occurrence with the other PDMs. Electronic supplementary material The online version of this article (10.1186/s12920-018-0327-0) contains supplementary material, which is available to authorized users.

We consider a gas-dynamic model of a one-dimensional flow of non-viscous perfect gas in the absence of heat conduction when a high-power localized heat source is switched on. Within the framework of this model, it is possible to thoroughly analyze the problem of the gas-flow regimes, which occur as a result of switch-on of such a source, in a wide range of values of the energy-deposition power and initial gas-dynamic characteristics of the flow. Eventually, we obtain a sufficiently general insight into the character of the resulting flows and the conditions of their realizations.

Clear cell renal cell carcinoma (ccRCC) is a common oncourological disease with a high mortality level. The incidence of this type of cancer is constantly increasing, while molecular mechanisms involved in the disease initiation and progression remain far from being fully understood. A problem of the search for novel markers is crucial for improvement of diagnosis and therapy of ccRCC. We have previously found that the disease is characterized by increased expression of the NETO2 gene. In the present study, we showed that isoform 1 (NM_018092.4) makes the main contribution to the upregulation of this gene. Using original CrossHub software, "The Cancer Genome Atlas" (TCGA) project data were analyzed to identify possible mechanisms of NETO2 gene activation in ccRCC. The absence of significant contribution of methylation to the increase of mRNA level of the gene was observed. At the same time, a number of genes encoding transcription factors, which could potentially regulate the expression of NETO2 in ccRCC, were identified. Three such genes (MYCBP, JMY, and SAP30) were selected for the further analysis of their mRNA levels in a set of ccRCC samples with quantitative PCR. We showed a significant increase in mRNA level of one of the examined genes, SAP30, and revealed its positive correlation with NETO2 gene expression. Thus, upregulation of NETO2 gene is first stipulated by the isoform 1 (NM_018092.4), and the probable mechanism of its activation is associated with the increased expression of SAP30 transcription factor.

A genotyping procedure based on single-step PCR and subsequent allele-specific hybridization on a hydrogel biochip was developed to address the polymorphisms of HERC2, OCA2, SLC24A4, SLC45A2, TYR, IRF4, MC1R,MITF, PIGU, MYH7B, NCOA6, and CDK10. Amplified gene fragments were fluorescently labeled in PCR, and fluorescent signals from biochip cells were detected to evaluate how efficiently the PCR product formed a perfect duplex with an immobilized probe. The analytical characteristics of hybridization analysis were estimated for several fluorophores with different optical spectra. Cyanine dyes fluorescing in the range of Cy5 and Cy7 were synthesized for the purpose and used as 5'-tags of universal primers in single-step PCR. A Cy7 analog fluorescing in the near infrared range was found to increase the sensitivity of hybridization analysis by producing a lower background signal in the cases where target gene amplification was low.

Background Neuropilin and tolloid-like 2 (NETO2) is a single-pass transmembrane protein that has been shown primarily implicated in neuron-specific processes. Upregulation of NETO2 gene was also detected in several cancer types. In colorectal cancer (CRC), it was associated with tumor progression, invasion, and metastasis, and seems to be involved in epithelial-mesenchymal transition (EMT). However, the mechanism of NETO2 action is still poorly understood. Results We have revealed significant increase in the expression of NETO2 gene and deregulation of eight EMT-related genes in CRC. Four of them were upregulated (TWIST1, SNAIL1, LEF1, and FOXA2); the mRNA levels of other genes (FOXA1, BMP2, BMP5, and SMAD7) were decreased. Expression of NETO2 gene was weakly correlated with that of genes involved in the EMT process. Conclusions We found considerable NETO2 upregulation, but no significant correlation between the expression of NETO2 and EMT-related genes in CRC. Thus, NETO2 may be involved in CRC progression, but is not directly associated with EMT.

// Marina Emelyanova 1 , Lilit Ghukasyan 1 , Ivan Abramov 1, 2 , Oxana Ryabaya 2 , Evgenia Stepanova 2 , Anna Kudryavtseva 1, 3 , Asiya Sadritdinova 1, 3 , Cholpon Dzhumakova 2 , Tatiana Belysheva 2 , Sergey Surzhikov 1 , Lyudmila Lyubchenko 2 , Alexander Zasedatelev 1, 2 and Tatiana Nasedkina 1, 2 1 Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russian Federation 2 Blokhin Cancer Research Center, Ministry of Health of the Russian Federation, Moscow, Russian Federation 3 P. Hertsen Moscow Oncology Research Institute, Moscow, Russian Federation Correspondence to: Marina Emelyanova, email: emel_marina@mail.ru Keywords: biochip, somatic mutations, melanoma, diagnostic tool, targeted therapy Received: December 30, 2016 Accepted: March 30, 2017 Published: April 10, 2017 ABSTRACT Target inhibitors are used for melanoma treatment, and their effectiveness depends on the tumor genotype. We developed a diagnostic biochip for the detection of 39 clinically relevant somatic mutations in the BRAF , NRAS , KIT , GNAQ , GNA11 , MAP2K1 and MAP2K2 genes. We used multiplex locked nucleic acid (LNA) PCR clamp for the preferable amplification of mutated over wild type DNA. The amplified fragments were labeled via the incorporation of fluorescently labeled dUTP during PCR and were hybridized with specific oligonucleotides immobilized on a biochip. This approach could detect 0.5% of mutated DNA in the sample analyzed. The method was validated on 253 clinical samples and six melanoma cell lines. Among 253 melanomas, 129 (51.0%) BRAF , 45 (17.8%) NRAS , 6 (2.4%) KIT , 4 (1.6%) GNAQ , 2 (0.8%) GNA11 , 2 (0.8%) MAP2K1 and no MAP2K2 gene mutations were detected by the biochip assay. The results were compared with Sanger sequencing, next generation sequencing and ARMS/Scorpion real-time PCR. The specimens with discordant results were subjected to LNA PCR clamp followed by sequencing. The results of this analysis were predominantly identical to the results obtained by the biochip assay. Infrequently, we identified rare somatic mutations. In the present study we demonstrate that the biochip-based assay can effectively detect somatic mutations in approximately 70% of melanoma patients, who may require specific targeted therapy.

Acral melanoma is one of the most aggressive and fast-growing forms of cutaneous melanoma and is characterized by a predominant location on the palms and feet. Primary tumors, metastases, and normal tissue samples from five acral melanoma patients were examined by massive parallel sequencing, focusing on the coding regions of 4100 genes involved in the origin and progression of hereditary and oncology diseases. Somatic mutations were found in genes related to cell division, proliferation, and apoptosis (BRAF, NRAS, VAV1, GATA1, and GCM2); cell adhesion (CTNND2 and ITGB4); angiogenesis (VEGFA); and the regulation of energy metabolism (BCS1L). Comparisons of target DNA sequences between morphologically normal and primary tumor tissues and between normal and metastatic tissues identified the candidate genes responsible for rapid metastasis in acral melanoma.

The formation of a jet of a nonequilibrium multiply charged ion plasma is studied in the inhomogeneous gas jet. It is shown that the geometrical divergence of the jet restricts the maximum ion charge state and results in the spatial localization of the discharge. Stationary solutions corresponding to such regimes are constructed. The model proposed can be used to optimize modern experiments on generation of hard UV radiation due to the line emission of multiply ionized atoms in a gas jet heated by high-power millimeter and submillimeter radiation.

We consider a gas-dynamic model describing the formation of a plasma with multiply ionized ions under the conditions of resonant heating of the electron component. Based on the isothermal approximation, possible regimes of the plasma flow are classified, the influence of the geometric divergence of the flow on the formation of the ion charge distribution is studied, and optimal regimes for the achievement of the maximum ion charge are identified. The model can be used for optimization and interpretation of modern experiments on generation of the extreme ultraviolet radiation due to the excitation of lines of multiply ionized atoms in a gas flow heated by strong millimeter or submillimeter waves.

A biochip-based method was developed to identify the BCR-ABL mutations that affect the thyrosine kinase domain and determine resistance to targeted therapy with thyrosine kinase inhibitors. The method is based on RT–PCR followed by allele-specific hybridization on a biochip with immobilized oligonucleotide probes. The biochip addresses 11 mutations, which are responsible for up to 85% of imatinib resistance cases. A method to decect the clinically significant mutation T315I was designed on the basis of LNA-clamped PCR and proved highly sensitive, detecting the mutation in clinical samples with a leukemic cell content of 5% or higher. The method was validated using clinical samples from chronic myeloid leukemia (CML) patients with acquired resistance to imatinib. The results of hybridization on biochip were verified by Sanger sequencing.

This paper presents a study of plasma flux characteristics flowing out from the gas-dynamic mirror trap along the magnetic field lines to a metal wall. The main feature of the current work is that the effect of ion acceleration by ambipolar potential is considered in the expander region. The developed model also takes into account a possibility of transition from the collisional expansion of electron flow in the vicinity of the magnetic plug to the collisionless regime. The developed model allows calculation of the ambipolar potential profile and plasma characteristics in the expander region.

Background Colorectal cancer (CRC) is a common cancer worldwide. The main cause of death in CRC includes tumor progression and metastasis. At molecular level, these processes may be triggered by epithelial-mesenchymal transition (EMT) and necessitates specific alterations in cell metabolism. Although several EMT-related metabolic changes have been described in CRC, the mechanism is still poorly understood. Results Using CrossHub software, we analyzed RNA-Seq expression profile data of CRC derived from The Cancer Genome Atlas (TCGA) project. Correlation analysis between the change in the expression of genes involved in glycolysis and EMT was performed. We obtained the set of genes with significant correlation coefficients, which included 21 EMT-related genes and a single glycolytic gene, HK3. The mRNA level of these genes was measured in 78 paired colorectal cancer samples by quantitative polymerase chain reaction (qPCR). Upregulation of HK3 and deregulation of 11 genes (COL1A1, TWIST1, NFATC1, GLIPR2, SFPR1, FLNA, GREM1, SFRP2, ZEB2, SPP1, and RARRES1) involved in EMT were found. The results of correlation study showed that the expression of HK3 demonstrated a strong correlation with 7 of the 21 examined genes (ZEB2, GREM1, TGFB3, TGFB1, SNAI2, TWIST1, and COL1A1) in CRC. Conclusions Upregulation of HK3 is associated with EMT in CRC and may be a crucial metabolic adaptation for rapid proliferation, survival, and metastases of CRC cells. Electronic supplementary material The online version of this article (10.1186/s12864-018-4477-4) contains supplementary material, which is available to authorized users.

We discuss a concept of a point-like source of the extreme ultraviolet (EUV) light based on a non-equilibrium microwave discharge in expanding jet of dense xenon plasma with multiply charged ions. A conversion efficiency of microwave radiation to EUV light is calculated, and physical constraints, and opportunities for future devices are considered. Special attention is given to trapping of spontaneous line emission inside a radiating plasma spot that significantly influences the efficiency of EUV light source., This is an author-created version of an article published in Physical Review Applied

A genotyping procedure based on single-step PCR and subsequent allele-specific hybridization on a hydrogel biochip was developed to address the polymorphisms of HERC2, OCA2, SLC24A4, SLC45A2, TYR, IRF4, MC1R,MITF, PIGU, MYH7B, NCOA6, and CDK10. Amplified gene fragments were fluorescently labeled in PCR, and fluorescent signals from biochip cells were detected to evaluate how efficiently the PCR product formed a perfect duplex with an immobilized probe. The analytical characteristics of hybridization analysis were estimated for several fluorophores with different optical spectra. Cyanine dyes fluorescing in the range of Cy5 and Cy7 were synthesized for the purpose and used as 5'-tags of universal primers in single-step PCR. A Cy7 analog fluorescing in the near infrared range was found to increase the sensitivity of hybridization analysis by producing a lower background signal in the cases where target gene amplification was low.

In order to expand the informational capabilities of molecular genetic research, new indotricarbocyanine dyes that fluoresce in the near infrared (IR) spectral region have been synthesized. The developed IR dyes were studied using a biochip-based test system for detection of mutations in the BRCA1/BRCA2 and CHECK2 genes associated with breast cancer. The fluorescent label was introduced to the analyzed DNA during PCR using primers labeled with the synthesized IR dyes. An analyzer that allows recording and processing of images of fluorescent microarrays in the IR spectral region was designed and manufactured. It has been shown that the use of the synthesized dyes enables to conduct analysis in the IR region and improve the reliability of medical diagnostic tests due to low fluorescence intensity of sample components as well as of a biochip substrate and the reagents used for analysis.

To expand the informational capabilities of molecular genetic research, on the biological microchips, new indotricarbocyanine dyes that fluoresce in the near infrared (IR) spectral region have been synthesized. The developed IR dyes were studied using a biochip-based test system for detection of mutations in the BRCA1/BRCA2 and CHECK2 genes associated with breast cancer. The fluorescent label was introduced to the analyzed DNA during PCR using primers labeled with the synthesized IR dyes. An analyzer that allows recording and processing of images of fluorescent microarrays in the IR spectral region was designed and manufactured. It has been shown that the use of the synthesized dyes enables to conduct analysis in the IR region and improve the reliability of medical diagnostic tests due to low fluorescence intensity of sample components as well as of a biochip substrate and the reagents used for analysis.

Clear cell renal cell carcinoma (ccRCC) is a common oncourological disease with a high mortality level. The incidence of this type of cancer is constantly increasing, while molecular mechanisms involved in the disease initiation and progression remain far from being fully understood. A problem of the search for novel markers is crucial for improvement of diagnosis and therapy of ccRCC. We have previously found that the disease is characterized by increased expression of the NETO2 gene. In the present study, we showed that isoform 1 (NM_018092.4) makes the main contribution to the upregulation of this gene. Using original CrossHub software, "The Cancer Genome Atlas" (TCGA) project data were analyzed to identify possible mechanisms of NETO2 gene activation in ccRCC. The absence of significant contribution of methylation to the increase of mRNA level of the gene was observed. At the same time, a number of genes encoding transcription factors, which could potentially regulate the expression of NETO2 in ccRCC, were identified. Three such genes (MYCBP, JMY, and SAP30) were selected for the further analysis of their mRNA levels in a set of ccRCC samples with quantitative PCR. We showed a significant increase in mRNA level of one of the examined genes, SAP30, and revealed its positive correlation with NETO2 gene expression. Thus, upregulation of NETO2 gene is first stipulated by the isoform 1 (NM_018092.4), and the probable mechanism of its activation is associated with the increased expression of SAP30 transcription factor.

We report the first direct demonstration of possibility to generate the extreme ultraviolet (EUV) radiation with a freely expanding jet of dense plasma with multiply-charged ions supported by high-power microwaves. The detected emission power is about 20 W at 18--50 nm for argon and xenon and 0.3 W at 13--17 nm for xenon. The discharge with a peak electron density up to $3\times 10^{16}\,$cm$^{-3}$ and a characteristic size of $150\,\mu$m is supported by a focused radiation of a recently developed gyrotron with unique characteristics, 250~kW output power at 250~GHz, operating in a relatively long (50$\,\mu$s) pulse mode. Up-scaling of these experimental results gives grounds for development of a point-like kilowatt-level EUV source for a high-resolution lithography able to fulfill requirements of the microelectronics industry., Comment: 5 pages, 3 figures, submitted to Appl. Phys. Lett. (2018)

In the present paper we target the physics of transition from subsonic to supersonic regimes in the expanding plasma flow. Originated form ECR ion sources, this problem is generalized to describe the stationary highly-localized plasma discharge formed under resonant microwave heating in a gas jet freely expanding after a high-pressure nozzle. The peculiar feature of such a discharge is formation of a strongly non-equilibrium plasma flow with multiply charged ions and the electron temperature much greater than the temperature of ions. We study possibilities for conjugating the slow movement of initially neutral dense gas and the supersonic flow of accelerated plasma, or, equivalently, a smooth transition from ion-acoustic barrier in the expanding flow with a varying charge state distribution. The proposed model is used to understand and optimize the recent experiments performed at IAP, Nizhny Novgorod, and aimed at demonstration of a new possibility of development of a point source of extreme ultraviolet r...

Infectious complications that arise during the treatment of children with acute leukemia with chemotherapeutic agents at high doses represent a serious problem in oncohematology. To find genetic conditions that may lead to the development of postchemotherapy infections, the genomes of 12 children with acute leukemia who had severe infectious complications during therapy were examined. At the same time, the coding regions of 17 genes involved in the regulation of the immune response were determined by massive parallel sequencing. The analysis revealed 39 nonsynonymous SNPs that lead to amino acid substitutions, including the following informative genetic markers: PTPN22 c.1858CT (rs2476601), TLR4 c.896AG (rs4986790) and TLR4 c.1196CT (rs4986791), IL7R c.197TC (rs1494555) and IL7R c.412GA (rs1494558). The results of massive parallel sequencing were validated by Sanger sequencing. The identification of genetic markers associated with the predisposition to infectious complications may allow one to assess the individual risk of the severe infection development in children with acute leukemia during the treatment with chemotherapeutic agents and to begin the development of personalized approaches to anticancer therapy.