[Mutation analysis of K-ras protooncogene in colorectal adenocarcinomas and polyps in Russian patients].

To estimate diagnostic value of K-ras mutations during cancer risk group formation, they were studied in the samples of sporadic carcinomas (n = 33) and malignant (n = 13) polyps of large intestine obtained during surgery or polypectomy. Using PCR analysis, restriction analysis, SSCP analysis and automated sequencing, eight various point mutations were revealed. Six of them were located in codon 12 and two, in codon 13 of the K-ras gene.

[Two CpG-islands of SEMA3B gene: methylation in clear cell renal cell carcinoma].

Earlier in some small cell lung (SCLC) and non-small cell lung carcinoma (NSCLC) cell lines, methylation of CpG-island was found in the SEMA3B region, which belongs to the first intron according to the NCBI data base (Build 36). The aim of this work was to study methylation of two SEMA3B CpG-islands: promoter and intronic in clear cell renal cell carcinoma (RCC). Using methyl specific PCR and bisulfite sequencing, it was shown for the first time that promoter CpG-island was methylated in RCC with high frequency 56% (34/61), and intronic CpG-island - with somewhat lower frequency 35% (17/48).

[Alteration of SEMA3B gene expression levels in epithelial tumors].

Gene expression decreasing in tumors permits to suggest tumor-suppressor activities for these genes. Thus, mRNA quantity decrease was found for SEMA3B gene in many cell lines of small cell (SCLC) and non-small cell lung carcinoma (NSCLC) and it is well-known that SEMA3B suppresses growth of the NCI-H1299 non-small cell lung carcinoma (NSCLC) cell line and tumor formation in nude mice. The aim of this work was to study spectrum of SEMA3B expression level in epithelial tumors of various locations.

[Methylation of promoter region of RASSF1A gene and frequencies of allelic imbalances in chromosome 3 critical regions are correlated with progression of clear cell renal cell carcinoma].

The short arm of chromosome 3 (3p) contains several critical regions harboring the set of genes with tumor suppressor activities. The RASSF1A gene (LUCA region, 3p21.31) shows various functions which can be associated with tumorigenesis.

[Analysis of K-ras, BRCA1/2, CHEK2 mutations and microsatellite markers (loss of heterozygosity at 9p, 17p and 18q) in sporadic pancreas adenocarcinomas].

The purpose of this study was to investigate informativety and clinical significance of most frequent somatic alterations in K-ras, TP53, CDKN2A, MADH4 and more uncommon mutations in BRCA1, BRCA2, CHEK2 genes, which arise on preinvasive stage in sporadic pancreatic adenocarcinomas (PA), in Russian patients. We examined surgically resected and manually microdissected primary PA tissue samples and samples of normal pancreatic tissue for 37 individuals. K-ras mutations in codon 12 were found in 24 tumors (0.