[Current principles in the screening, diagnosis, and therapy of colorectal cancer].

The data available in the literature on the prevalence of colorectal cancer (CRC), its risk factors and genetic aspects are analyzed. Basic screening tests and their diagnostic value are described. The paper indicates the importance of methods (colonoscopy, occult blood feces analysis, fecal immunochemical test, determination of molecular genetic profile of fecal enterocytes) for the early primary diagnosis of colonic epithelial tumors and techniques (echography, computed tomography, magnetic resonance imaging, positron emission tomography) that are required to specify clinical TNM staging and enable one to choose an optimal treatment policy for CRC patients owing to the estimation of tumor volume and to the diagnosis of reginal and distant metastases. It also shows that new screening methods based on the detection of molecular markers for early (premorphological) tumor stages are promising. The role of primary CRC prevention aimed at molding and maintaining a healthy lifestyle in the population is demonstrated.

[Genome-wide analysis of DNA methylation in prostate cancer using the technology of Infinium HumanMethylation450 BeadChip (HM450)].

Using the technology of DNA chips Infinium HumanMethylation 450 BeadChip it was analyzed quantitative DNA methylation status in 12 paired samples of prostate adenocarcinoma, and morphologically altered tissues. Analysis of differentially methylated regions of the genome showed an association with abnormal status for 21610 and 3852 hypomethylated hyper-methylated CpG sites. Dominance in the cancer genome hypermethylated sites and their predominant localization in the regulatory regions of genes indicate their possible role in the implementation of mechanisms of gene suppression in the pathogenesis of prostate cancer (PCa). For 14 genes studied were characterized array maximum values hypermethylation in promoter region (> 50% CpG sites) in combination with a high level of methylation differences between treatment groups (> 40%). Role of hypermethylation in some of them: AOX1, KLF8, ZNF154, TMEM106A in the pathogenesis of prostate cancer has been showed previously. Hypermethylation of genes ACSS3, TAC1, TUBA4B, ZSCAN12 not previously been shown for prostate cancer, but is characterized by the association with other cancers. In turn, the differences in the levels of methylation in genes GPRASP1, NKX2-6, ARX, CYBA, EPSTI1, RHCG been documented as a result of a number of genome-research oncology, but has not been studied in detail. To assess the diagnostic potential of epigenetic markers of prostate cancer there was carried out unbiased selection of individual CpG sites most reliably discriminate against tumor samples from a group of no tumor samples. In selected diagnostic model based on logistic regression included 9 CpG sites. Validation of the model was carried out on an independent dataset of methylation of 40 paired samples from the prostate cancer project Atlas of Cancer Genome (TCGA) analyzed on the same version of the DNA chip. Summarized rates of diagnostic informativeness of a model (specificity 95%, sensitivity of 97%, the area under the curve of the diagnostic test (ROC) - 0,96), obtained after validation, allow us to consider these CpG Sites as potential markers for molecular diagnosis of prostate cancer.

[Molecular mechanisms of lung cancer development at its different stages in nuclear industry workers].

OBJECTIVE: to assess mutational events in exons 5, 7, and 8 of the p53 gene and to reveal mutant p53 protein in verified cases of morphologically altered (proliferative and precancerous changes, lung cancer) and histologically unaltered, lung tissues in workers exposed to occupational radiation. MATERIAL AND METHODS: The investigation used formalin-fixed paraffin-embedded unaltered and altered lung tissue blocks (FFPBs) obtained from the human radiobiological tissue repository. The shelf-life of FFPBs was 5-31 years. An immunohistochemical technique using mouse antibodies against p53 protein (<>, Denmark), stained with diaminobenzidine (DAB) chromogen, was employed to determine p53 protein. DNA was isolated from lung tissue FFPBs with QIAmp DNA FFPE Tissue Kit, (<>, USA). Polymerase chain reaction (PCR) was performed to amplify the p53 gene exons 5, 7, and 8 selected for examination, by applying the sequences of genes and primers, the specificity of which was checked using the online resource (http://www.ncbi.nlm.nih.gov/blast). PCR products were detected by temporal temperature gradient gel-electrophoresis and the Sanger sequencing method. The obtained DNA fragments were analyzed on a sequencer ABI Prism 3100 Genetic Analizer (<>, USA). Computer-aided DNA analysis was made using the BLAST program. A package of applied Statistica 6.0 programs was employed for statistical data processing. Results. Immunohistochemical analysis showed that mutant p53 protein was absent in the cells of unaltered lung tissue and the number of cells with mutant p53 protein increased in all the patients with proliferative and precancerous changes and lung cancer, suggesting p53 protein dysfunction. The total number of p53 gene mutations in exons 5, 7, and 8, if there were proliferative and precancerous lung tissue changes and lung cancer, were 25, 20, and 40%, respectively. All the found mutations were transversions (the substitution of purine for pyrimidine or, conversely), indicating the action of exogenous mutagens. CONCLUSION: The results of this investigation have confirmed other investigators' data showing that p53 gene mutations in lung cancer are observed in 40-70% of cases. The differences in the number of cases of altered lung tissue with mutations in the p53 gene (not more than 40%) and in those of p53 protein expression were found in 100%, suggesting the regulation of p53 gene function in the cell at multiple levels.