Aim: To find putative diagnostic markers for clear cell renal cell carcinomas (ccRCC). Material and methods: Quantitative polymerase chain reaction (Q-PCR), bisulfite treatment, methylation-specific PCR, analysis on cBioPortal for Cancer Genomics. Results: We have found that expression of GPX 1, GPX3, and GPX4 genes was decreased in ccRCC. We have shown that the number of alanine (GCG) repeats at the amino terminus of the GPX1 protein is variable. It was reported earlier that an allele that possess 5 alanine repeats is associated with the increased cancer risk. According to the obtained data, the allele with the 5 alanine repeats was also present in a group of healthy donors. Moreover, the frequency of alleles with repeats was similar among ccRCC patients and healthy individuals. We found that decreased expression of GPXs genes was not associated with promoter methylation. To provide other explanation, an analysis on the gene copy number was performed. We have found the heterozygous deletions for GPX1 gene, amplification for GPX3 gene, and no change in gene copy number for GPX4. Conclusions: Our data support the hypothesis that GPX1, GPX3, and GPX4 genes may play a role in ccRCC cancerogenesis and therefore they might be considered as putative diagnostic markers for ccRCC.

Aim. To investigate the expression levels of

Aim. The work is devoted to the development of less invasive tools for the colorectal cancer (CRC) screening. Methods. Q-PCR and methylation-specific PCR techniques were used in the current work. Results. We have shown that the levels of cell-free plasma DNA are higher in the CRC patients compared with the healthy donors (p < 0.01). Hypermethylation of APC, FHIT, LRRC3B and HIC1 genes was studied in the tumor and plasma samples of CRC patients. Two-stage verification for CRC screening was proposed. Conclusions. We proposed and tested a novel approach for CRC screening based on the determination of cell-free DNA and methylated DNA fragments in the plasma.

Aim. To find putative diagnostic and prognostic markers of cancerogenesis. Methods. Analysis of microarray and SAGE data, quantitative PCR (Q-PCR), bisulfite sequencing, methylation-specific PCR. Results. Bioinformatic analysis of microarray and SAGE database revealed that genes, encoding the glutathione peroxidase 1 and 3 (GPX1 and GPX3) were expressed at low levels in renal cancers. The relative gene expression of GPX1 and GPX3 that was widely inactivated in clear-cell renal cell carcinoma (ccRCC) was confirmed by Q-PCR. No correlation between expression levels and promoter methylation was found. It was found, however, that an allele with five ALA repeats in the N-terminal region of GPX1 is the most frequent polymorphic variant in ccRCC patients. Conclusions. Our data support the hypothesis that GPX1 and GPX3 are involved in tumorigenesis of ccRCC and could be putative TSGs (tumor suppressor genes) in renal cancer

Aim.To discover the mechanisms of the PPM1M and PRICKLE2 genes expression alterations in clear cell renal cell carcinomas. Methods. Study of the copy number was performed, using the quantitative PCR (Q-PCR). Results. Deletions of PPM1M were found in 55 % of cases, amplifi cations -in 17 % and in 28 % of samples there were no changes of the copy number. We found the deletions of PRICKLE2 in 50 % of samples, no changes of the copy number in 39 %, and amplifi cations in 11 % of cases. Conclusions. By the analysis of the gene copy number we have shown that homo-and heterozygous deletions are the main reason of changes in expression of the PPM1M and PRICKLE2 genes. K e y w o r d s: clear cell renal cell carcinoma, heterozygous deletions, quantitative PCR, copy number analysis.