Apoptosis (programmed cell death) is essential machinery for multicellular organisms. Apoptosis plays an important role in cell differentiation, damaged cell elimination and immune system homeostasis. This review is focused on various mechanisms of signal transduction through caspase-2 which believed to be one of the most enigmatical protease involved in apoptosis. Caspase-2 is activated upon stimulation by such agents as genotoxic stress, death receptors ligation, ER stress, metabolic changes, etc. In addition, caspase-2 may act as a tumor suppressor and has been implicated in cell response to oxidative stress and neurodegenerative progression during ischemic brain damage. Thus, variety of signal pathways triggered by caspase-2 place this protease apart from other members of the family and suggests a prominent role in apoptosis. Here, we analyse different functions of this unique caspase and discuss possible applications of accumulated knowledge in advanced oncology and medicine.

Transfer of mtDNA in the nuclear genome is usually regarded as a continued and dynamic process of forming numt-pseudogenes or numt-insertions. They can be regarded not only as a neutral polymorphism, but may be involved in oncogenesis, aging and genetic diseases. Experimental identification of numt-insertions arising de novo is limited due to the presence of numerous homology mtDNA constitutively existing in the nuclear genomes of eukaryotes. It is known that the chick nuclear DNA (nDNA) constitutively contains 12 numt-pseudogenes. We attempted to experimentally detect the formation of numt-insertions de novo in the nDNA of chick embryos (Gallus gallus) from the eggs exposed to X-rays. Free mtDNAs were removed from preparations of nDNA of liver embryos through double gel electrophoresis. Numt-inserts in nDNA of control and survival embryos (from irradiated eggs) were revealed by PCR using 11 pairs of primers flanking the region of mtDNA of about 300-400 bp. PCR analysis with nDNA of control group showed no presence of homology mtDNA amplified with selected primers. PCR assays of nDNA of eight embryos from irradiated eggs showed that nDNA of two embryos contained new sites of mtDNA. PCR amplification of 3 loci of mtDNA is stably detected in nDNA from one embryo and 4 loci of mtDNA in nDNA from another embryo. Sequencing of PCR amplicons synthesized on templates of these nDNA showed that their sequences are identical to mtDNA and accurately cover the sites of several genes and the site of mtDNA D-loop. Thus, the experimental results indicate that ionizing radiation can induce integration of mtDNA fragments in the nuclear genome, apparently, through the mechanism of nonhomologous end-joining repair of double-strand breaks of nDNA.

An association between polymorphous (allelic) variants of genes of the 1st Phase of enzymatic xenobiotic biotransformation (EXB) in the superfamily of cytochromes P450 gene CYP1A1 * 2A (ml polymorphism), CYP1A1 * 2C (m2 polymorphism), gene CYP2E1 * 6 (C polymorphism), and between polymorphous vari- ants of gene of the 2nd EXB Phase of mircosomal epoxide hydrolase mEPOX Tyr113His (EH3 polymor- phism), and mEPOXHis139Arg (EH4 polymorphism) and lung cancer in Mayak workers with occupational prolonged exposure was studied. Analysis of population genotype frequency and alleles of genes CYP1A1 * 2A, CYP1A1 * 2C, CYP2E1 * 6, mEPOX Tyr113His, and mEPOXHis139Arg was conducted in the group of Mayak workers (289 individuals). The study has shown their compliance with the Hardy-Weinberg equilibrium, and correspondence of the genotype frequency to their frequency in European population. The study was per- formed using case-control method. Case-group consisted of 49 Mayak workers with verified diagnosis of lung cancer. Control-group consisted of 172 Mayak workers without lung cancer registered at the moment of the research. There was an increasing trend in odds ratio (OR) of lung cancer among homozygous carriers of the mutation in pp gene CYP1A1 * 2A, heterozygous carriers of the mutation in wp gene mEPOX Tyr113His and homozygous carriers ofww gene CYP2E1 * 6; also, there was a decreasing trend in OR among heterozy- gous carriers of wp gene CYP2E1 * 6. Two variants of pair allelic combinations of genes (genotypes ww CYP1A1 * 2A/genotype wp mEPOX Tyr113His, and genotype ww CYP2E1 * 6/genotype wp mEPOX Tyr113His) were revealed, which carriers had a statistically significant increase in the odds ratio of lung can- cer. With regard to these variants of genotype combinations, OR of lung cancer was 2.01 (CI 95%: 1.04-3.91) and 2.09 (CI 95%: 1.08-4.03), correspondingly.

Numerical impairments in genes or some genome sites - gene amplifications or deletions - are one of the most frequent genetic mutations occurring in breast cancer. Gene amplifications in breast cancer, their frequency, prognostic value, and the possible role of these disorders in the identification of the subtypes of this heterogeneous disease are considered.

Determination of the HER2 status of tumor cells in stomach and breast cancer is a routine diagnostic method. Immunohistochemical study is sufficient for its evaluation in most cases. However, a specifying molecular genetic study using the FISH technique is performed when borderline results are obtained. The paper describes the new procedure IQFISH that allows the results to be obtained in one working day.

MicroRNAs are known as a posttranscriptional negative regulators of gene expression by binding to the 3'UTP of target mRNAs in cytoplasm. More than 1600 microRNAs expressed in human cells, are involved in the regulation of embryogenesis, differentiation, cell cycle, apoptosis, senescence, thus determining cell fate. Up to 60 % of protein coding genes are under their control. Various sets of microRNAs found in different human tissues under normal and pathological conditions, including cancer, suggest that miRNAs are involved in most cellular pathways. To date, there is no doubt that regulatory potential of the genome is largely determined by miRNAs. In our study, we performed a comparative phylogenetic analysis of the origin and evolution of the total set of 1048 miRNAs in the human genome and investigated the role of certain miRNAs in carcinogenesis of thyroid and mammary glands, as potential diagnostic and prognostic biomarkers of malignancy. Analysis of phylogenetic distribution of miRNAs in the human genome has shown four peaks of appearance of new miRNA genes in the evolution from Methazoa to H. sapiens. The highest amount of new miRNA genes appeared after divergence of H. s. from common ancestor with P. t. Expansion of transposable elements in genome was accompanied by the origin of new miRNA genes on the basis of their sequences. More than 14 % from 1600 miRNAs of human genome originated from mobile elements and still remain. Profiles of expression of 5 miRNAs, pertaining to oncomicroRNAs - miR-21, -221, -222, -155 and -205 - allow distinguishing ductal invasive carcinoma of mammary gland and thyroid papillary carcinoma. The data obtained suggest different ways and roles of participation of the same miRNAs in carcinogenesis of thyroid and mammary glands. So, these miRNAs and profiles of their expression might be used in the diagnosis and prognosis of cancer.

The DNA polymerase iota (Pol iota), which has some peculiar features and is characterized by an extremely error-prone DNA synthesis, belongs to the group of enzymes preferentially activated by Mn2+ instead of Mg2+. In this work, the effect of Mn2+ on DNA synthesis in cell extracts from a) normal human and murine tissues, b) human tumor (uveal melanoma), and c) cultured human tumor cell lines SKOV-3 and HL-60 was tested. Each group displayed characteristic features of Mn-dependent DNA synthesis. The changes in the Mn-dependent DNA synthesis caused by malignant transformation of normal tissues are described. It was also shown that the error-prone DNA synthesis catalyzed by Pol iota in extracts of all cell types was efficiently suppressed by an RNA aptamer (IKL5) against Pol iota obtained in our work earlier. The obtained results suggest that IKL5 might be used to suppress the enhanced activity of Pol iota in tumor cells.

MicroRNA regulates gene expression, is involved in many cellular processes, and plays an important role in the development of cancer. The regulation of the expression of miRNA genes can be achieved by methylating their CpG islands, which is shown in different types of tumors. The methylation of miRNA genes in clear cell renal cell carcinoma (CCRCC) has mainly been studied for the miR-9 and miR-34 families. The methylation of six miRNA genes (miR-124a-2, -124a-3, -9-1, -9-3, -34b/c, -129-2) was investigated with the use of representative set of CCRCC samples (46 cases). Methylation of three genes miR-124a-2, -124a-3, and -129-2 was studied in kidney tumors for the first time. Methylation analysis was performed using methyl specific PCR. It is shown that the frequency of methylation of six genes (miR-124a-2, -124a-3, -9-1, -9-3, -34b/c and -129-2) was significantly higher in tumor samples than in samples of histologically normal tissue (P < 3 x 10(-5) by Fisher's exact test). These results suggest the properties of tumor suppressors for the six miRNA genes indicated in CCRCC. We also found correlations between the methylation frequency of some miRNA genes and signs of the progression of CCRCC (tumor size, clinical stage, loss of differentiation, and metastasis).

Translocator protein TSPO and MAPK signaling partway are important regulators of numerous cell functions including carcinogenesis, cell proliferation and apoptosis. We have studied MAPK inhibitor UO126 and TSPO specific ligand PK11195 effects on TSPO expression level in melanoma cells. Using immunocytochemical staining, we have detected increased expression of TSPO after incubation with PK11195 and UO126 in all concentrations. These results were confirmed by real time PCR: the increase in mRNA TSPO expression level was detected after incubation with PK11195 in concentration 100 nmol/L, and with UO126 in concentration 10 micromol/L. In the case of a combination of treatments with PK11195 and UO126, we also observed an increase in the level of TSPO expression. So, we conclus de that TSPO ligand PK11195 and MAPK signaling partway inhibitor UO126 modulate TSPO expression. These data are crucial for indentifying of regulatory processes for TSPO expression. Pathogenetic interconnection between MAPK signaling partway and TSPO is important for novel therapeutic approaches in melanoma treatment.

This review describes the most popular methods of search for serological markers of tumors that are used in clinical setting, provided with comparison of their efficiency.

The dynamics of expression of the RT1A antigen of the class I major histocompatibility complex (MHC) in a Walker 256 tumor after its transplantation into Brattleboro rats with a genetic defect of Arginine-Vasopressin synthesis in the hypothalamus was studied. Expression of the RT1A antigen was detected by means of Western-blotting and flow cytometry in the tumor cells on the 14th-17th days after transplantation. In addition, a simultaneous increase in the portion of cells that express the RT1A antigen and in the level of its expression per cell was observed. It is presupposed that at a deficiency of Arginine-Vasopressin, a renewal of expression of the class I MHC antigens, which results in an increase of immunogenicity of this tumor and regression, occurs in the Walker 256 tumor in the Brattleboro rats.

We present a series of 51 medulloblastoma in children under three years, collected in N.N. Burdenko Neurosurgical Institute from 2000 to 2010. 57% of the tumors showed desmoplastic/nodular histology. Performed fluorescence in situ hybridization (FISH) analysis revealed the MYC oncogene amplification in 4%, the MYCN oncogene amplification - in 8%, isochromosome 17q - in 16% of cases. 9q deletion was found in 8% of desmoplastic/ nodular medulloblastomas. Our results showed that desmoplastic/nodular medulloblastoma has a positive predictive value for progression-free survival. Another feature of a biology of medulloblastomas in children younger than three years is the lack of nuclear accumulation of beta-catenin, and 6q deletion. Medulloblastomas with MYCN oncogene amplification often exhibit desmoplastic/nodular histology and a relatively favorable outcome. The most unfavorable prognostic marker is the MYC oncogene amplification, which in our series of 100% combined with the large cell/anaplastic medulloblastoma and isochromosome 17q - such tumors should be included in the "high risk" protocol.

The mRNA levels of P53gene, as well as NPM1, Kras, c-Myc, p14(ARF) genes, which, according to the published data, code for the proteins regulating the p53 activity, were studied using RT-PCR method in blood cells of patients with different localization of tumor process (prostate cancer, breast cancer and head and neck cancer) before and after application of radiation therapy. Changes in gene expression of cancer patients were compared with the control group of healthy donors. We have established that all patients had a decreased level of the Kras gene expression even before radiotherapy; moreover, the group of patients with prostate cancer had a low content of mRNA in NPM1 and p14(ARF), and the group of patients with head and neck cancerhad a reliably reduced mRNA in P53, NPM1 and p14(ARF). The radiation therapy did not cause essential changes in the expression of these genes of cancer patients, ecpect for the Kras gene, whose the mRNA level in the group of patients with head and neck cancer was reliably lower than the mRNA level prior to beginning of radiation therapy. The correlations of P53, NPM1, Kras, p14(ARF) gene expression were studied. We have shown that p14(ARF) mRNA level negatively correlates with Kras mRNA (R = -0.6, p = 0.002) and P53 mRNA levels (R = -0.49, p = 0.013) in the control group of healthy donors. A positive correlation was observed between P53 mRNA and NPM1 mRNA (R = 0.54, p = 0.006). Similar correlations between mRNA levels of these genes in blood cells were absent in the cancer patients before radiotherapy. After radiotherapy in patients with prostate cancer, p14(ARF) mRNA level positively correlated with NPM1 mRNA (R = 0.7, p = 0.001) and negatively with Kras mRNA (R = - 0.5, p = 0.03). Our results provide evidence that expression P53, NPM1, Kras and p14(ARF) genes may be coordinated in blood cells of healthy donors. The low expression levels of the studied genes in patients can contribute to the increase in the mutation changes in blood cells of the examined subjects after the action of genotoxic factors.

The leading risk factors of breast cancer (BC) were found to affect the efficiency of mammographic screening. The BC screening covered 26 912 women in 2001-2010. Its risk factors were identified using a questionnaire survey. During the BC screening, all the women underwent mammography in the frontal and oblique projections. The BIRADS scale was used to evaluate breast X-ray density. The performed examination revealed that the number of risk factors for BC directly affected its stage. The diagnostic efficiency of screening mammography was found to decline in the groups of patients with high breast X-ray density. The paper provides evidence that it is important to monitor groups of patients having BC risk factors and that it is expedient to estimate breast X-ray density. The frequency of BRCA1/2 gene mutations was determined in patients with BC identified during the mammographic screening. A relationship was found between the diagnosis of end-stage BC and the presence of BRCA1/2 gene mutations.

The paper considers the current aspects of the morphology, immunohistochemistry, molecular biology of liposarcomas. Particular attention is given to the embryogenesis of liposarcomas and to problems in the immunohistochemical diagnosis of these neoplasms. There is evidence that TLS-CHOP is involved in the PNA processing of liposarcoma cells. Prospects for the diagnosis and treatment of malignant mesenchymal tumors are discussed.

Benign metastasizing leiomyoma (ICD.0 8898/1) is a rare phenomenon characterized by multiple benign smooth muscle tumors (metastases) in the organs and tissues of patients with uterine leiomyoma without evidence for another tumor process. This tumor should be differentiated from leiomyosarcoma, at the same time account must be taken of the fact that its morphological criteria are not always effective. Molecular genetic testing is a more accurate method that allows valid differentiation of leiomyoma from leiomyosarcoma. Genetic testing is used to estimate losses of heterozygosity and microsatellite instability, which are characteristic of leiomyosarcoma only. The paper describes a clinical case of benign metastasizing leiomyoma in a 54-year-old patient with uterine myoma and pelvic lymph node metastasis. Molecular genetic testing was carried out using the samples obtained from primary uterine leiomyoma, morphologically altered ovarian tissue, and lymph node metastasis to determine the common origin of tumors in the uterus and lymph node and to reveal the benign or malignant nature of these neoplasms. Despite the fact that the term "benign metastasizing leiomyoma" is widely accepted in the world literature, neither these tumors nor metastases have morphological or genetic signs of malignancy so we consider the term "systemic leiomyomatosis" to better reflect the essence of this process.

Medulloblastoma is a heterogeneous disease with molecular variants and distinct biological behavior. Studying molecular abnormalities in medulloblastomas will allow to stratify patients into key populations and optimize aduvant therapy reducing long-term adverse effects.

Despite the advances of modern medicine, malignant glioblastoma cure remains an elusive goal. Both the invasive nature and location in vital areas of the brain make this type of tumors difficult for surgical treatment, while the current adjuvant therapy is not as successful as expected. Frequent recurrence and invasiveness of malignant gliomas is due to resistance of glioma stem cells to conventional radiation and chemotherapy. Technological advances in constructing recombinant viruses have allowed creating strains with high oncolytic activity toward glial tumors. Many of these strains have passed Phase I of clinical trials and demonstrated high safety. Despite the obvious potential of the approach, efficiency of the existing strains is still far from being sufficient for effectively curing the disease and require further improvement. The review summarizes results obtained with the most successful variants of oncolytic viruses that come down to the clinical trials and discusses the prospects for new approaches in virotherapy of malignant gliomas.