[Germline and Somatic Mutations in Archived Breast Cancer Specimens of Different Subtypes].

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.

[A clinical and genetic analysis of risk factors for the development of acute and chronic cerebral ischemia]. / Kliniko-geneticheskii analiz faktorov riska razvitiia ostroi i khronicheskoi ishemii golovnogo mozga.

To study the association between polymorphic markers in the ACE, SERPINE1, FGB, F5, F7, F12, GP1BA, GPIIIa, MTHFR, CYP11B2, PON1, PON2, NOS2, NOS2, HIFla, LTA, ALOX5AP genes and clinical characteristics of acute and chronic forms of circulatory disorders of the brain. MATERIAL AND METHODS: The analysis of polymorphic variants in ACE, FGB, F5, F7, F12, GP1BA, GPIIIa, SERPINE1, MTHFR, CYP11B2, PON1, PON2, NOS2, NOS3, PDE4D, HIF1a, LTA, ALOX5AP in 81 patients with chronic cerebral ischemia (CCI) and 69 patients with ischemic stroke (IS), and their interrelation with clinical manifestations of disease were investigated. RESULTS AND CONCLUSION: The association between the T/T genotype of the PDE4D SNP 83C>T polymorphism and a rapid progression of hypertensive disease (GB) was revealed (OR=6.22, CI=1.86-20.79, p=0.0036) in the group of patients with CCI. The association of the allele D and the DD genotype of the ACE (I>D, rs1799752) with cardioembolic stroke (OR=2.67, 95% CI=1.23-5.8, p=0.02 and OR=7.14, 95% CI=1.72-29.69, p=0.0057) was found. When comparing subgroups of patients with different degrees of stenosis of brachiocephalic arteries (BCA), the association of the allele C and the TC genotype of the GP1BA (rs2243093, -5T/C) with BCA occlusion and expressed hemodynamically significant stenosis (>75%) was revealed (OR=3.39, 95% CI=1.12-10.25, p=0.03 and OR=4.44, 95% CI=1.27-15.54, p=0.023, respectively). Thus, polymorphic markers in PDE4D, ACE, GP1BA in combination with certain clinical characteristics are risk factors for the progression of CCI and development of IS.

[Identification of Fusion Transcripts in Leukеmic Cells by Whole-Transcriptome Sequencing].

Genetic aberrations in leukemia often lead to the formation of expressed chimeric genes, which should be assessed for proper diagnosis and therapy. Modern methods of molecular diagnostic mainly allow to identify already known fusion genes. RNAseq is an efficient tool for identification of rare and novel chimeric transcripts. Here we present the results of the whole transcriptome analysis of bone marrow samples from five patients with acute myeloblastic leukemia and one, with myelodysplastic syndrome. The whole-transcriptome analysis was performed using Illumina/Solexa approach. We found rare or unknown chimeric transcripts including ETV6-MDS1, MN1-ETV6, OAZ1-PTMA, and MLLT10-GRIA4. Each of these transcripts was confirmed by RT-PCR and Sanger sequencing.

[Detection of BCR-ABL gene mutations in chronic myeloid leukemia using biochips].

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.

[Biological microchip for establishing the structure of fusion transcripts involving MLL in children with acute leukemia].

MLL is involved in fusion genes with more than 100 partner genes, approximately 80 of which have been characterized at the molecular level. MLL fusion genes are often found in infants (60-80% of acute lymphoblastic leukemia (ALL) cases and 40-50% of acute myeloblastic leukemia (AML) cases) and are appreciably rarer (8-10%) in children older than 1 year of age. MLL rearrangements are important markers in diagnosis and treatment choice. To identify the partner gene is of primary importance for prognosis and minimal residual disease monitoring. The structure of the fusion gene, including localization of the MLL breakpoints, is also informative. A method was developed to examine the fusion transcripts in order to identify the partner gene among the six most common ones and to establish the exon structure of the rearranged MLL. The method includes a multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) to amplify and to fluorescently label a fusion transcript fragment and subsequent hybridization of the product on a biological microchip with immobilized oligonucleotides complementary to exons of MLL and its partner genes AFF1, MLLT1, MLLT3, MLLT4, MLLT10, and ELL. Hybridization results were verified by sequencing the RT-PCR products and, in some cases, performing long-distance inverse PCR (LDI-PCR). The study involved 38 bone marrow samples from ALL patients (including 33 children younger than 1 year of age) and 15 samples from AML patients (including 10 from children younger than 1 year of age). The main partner genes were AFF1 (49%), MLLT1 (27%), MLLT3 (12%), and MLLT10 (12%) in ALL and MLLT3 (80%), MLLT10 (10%), and MLLT4 (10%) in AML. Fusion gene transcripts most commonly included MLL exon 11 (58% of ALL cases and 50% of AML cases), suggesting a breakpoint in MLL intron 11.