The Role of Methylation of a Group of microRNA Genes in the Pathogenesis of Metastatic Renal Cell Carcinoma.

The role of methylation of 9 miRNA genes in the pathogenesis of metastatic clear cell renal cell carcinoma was determined by quantitative methylation-specific PCR (MS-PCR). For 5 genes (MIR125B-1, MIR137, MIR193A, MIR34B/C, and MIR375), a significant correlation of high methylation level with late (III-IV) stages, large size (T3+T4) of the tumor, and metastasis to lymph nodes and/or distant organs was revealed. For another group of genes (MIR125B-1, MIR1258, MIR193A, MIR34B/C, and MIR375), a statistically significant correlation of high methylation level with loss of differentiation in the tumor (G3-G4) was found, and the opposite pattern was found for MIR203A. A total of 7 microRNA genes (MIR125B-1, MIR1258, MIR137, MIR193A, MIR203A, MIR34B/C, and MIR375) were identified, the methylation of which is associated with the progression of metastatic clear cell renal cell carcinoma. For 6 of them (except MIR34B/C) these data were obtained for the first time. Thus, new factors of the development and progression of clear cell renal cell carcinoma were identified as potential biomarkers for the early diagnosis and prognosis of metastatic clear cell renal cell carcinoma.

Relationship of the Levels of microRNA Gene Methylation with the Level of Their Expression and Pathomorphological Characteristics of Breast Cancer.

We studied the relationship of the levels of microRNA group expression and methylation with clinical and pathomorphological parameters of breast cancer and its immunohistochemical status. Quantitative methylation specific PCR analysis showed a significant (p<0.001) increase in the methylation level of 4 microRNA genes (MIR127, MIR129-2, MIR132, and MIR148A) and a significant (p<0.001) decrease for gene MIR375 relative to paired histologically normal tissue. Real-time PCR analysis revealed a significant (p≤0.001) decrease in the expression of 4 microRNAs (miR-127-5p, miR-129-5p, miR-132-3p, and miR-148a-3p) and a significant (p≤0.001) increase in the expression of miR-375-3p. A significant (rs=-0.6--0.7, p≤0.001) relationship between changes in the expression level of miR-129-5p, miR-132-3p, miR-148a-3p, and miR-375-3p and the levels of methylation of the corresponding genes in breast cancer was showed by using Spearman's rank correlation test. Analysis of the samples with consideration of the pathophysiological characteristics of the tumor revealed two significant markers of tumor progression: MIR129-2/miR-129-5p and MIR375/miR-375-3p. Both factors, the increase in the level of MIR129-2 methylation (p<0.001) and a decrease in the expression level of miR-129-5p (p<0.001), are significantly associated (p<0.001) with stage III/IV and the absence of HER2 expression. For MIR375/miR-375-3p, on the contrary, an association of low methylation level and enhanced expression with increased Ki-67 level (>30%, p<0.05) was revealed. These findings are of interest for understanding the mechanisms of breast cancer development and can provide the basis for the diagnosis and prognosis of the course of this disease. Moreover, the revealed features can be useful for adjusting the course of treatment with consideration of the pathophysiological characteristics of the tumor.

Association of Molecular Genetic Markers of TP53, MDM2, and CDKN1A Genes with Progression-Free Survival of Patients with Ovarian Cancer after Platinum-Based Chemotherapy.

We studied the association of polymorphic markers of cell cycle control genes (Arg72Pro of the TP53 gene, T(-410)G of the MDM2 gene, and Ser31Arg of the CDKN1A gene) in ovarian cancer and progression-free survival following platinum-based chemotherapy. Tumor tissue samples obtained from 49 patients who had undergone chemotherapy were examined. Patients received standard platinum-based chemotherapy and were observed until disease progression. Polymorphic markers of genes were evaluated by PCR-RFLP and real-time PCR. In patients carrying the G allele of the T(-410)G marker of the MDM2 gene, a decreasing trend was observed in median progression-free survival. An increase in the median progression-free survival was observed in carriers of the Pro allele of the TP53 gene (p=0.045). Furthermore, a stronger association was noted with carriers of the minor Pro/Pro homozygous genotype relative to the Arg/Arg genotype (p=0.007). In the subgroup of patients who underwent optimal or complete cytoreductive surgery, carriage of the minor Arg allele of the Ser31Arg marker (CDN1A gene) was associated with a decrease in the median progression-free survival time (p=0.004).

The Role of Polymorphic Markers rs1478604, rs2292305, and rs2228262 in THBS1 Gene in the Development of Autoimmune Dry Eye Syndrome.

An association of polymorphic marker rs2228262 in the THBS1 gene with the risk of developing dry eye in Sjögren syndrome was revealed. Confocal microscopy data suggest that this polymorphic marker is responsible for the high probability of corneal nerve fiber lesion in Sjögren syndrome even in the absence of clinical and functional signs of dry eye syndrome. A significant correlation was established between polymorphic markers rs1478604, rs2228262 in THBS1 gene and the coefficients of anisotropy and orientation symmetry of corneal nerve fibers. These results allow considering these polymorphic markers as a genetic factor of predisposition to dry eye syndrome in patients with Sjögren syndrome.

Marker Systems Based on MicroRNA Gene Methylation for the Diagnosis of Stage I-II Breast Cancer.

Groups of microRNA genes, methylation of which is associated with the initial (I-II) stages of breast cancer, are determined, and new markers and marker systems for the disease diagnosis were created on the basis of these data. A total of 14 genes in which methylation was associated with breast cancer were identified with the use of methyl-specific PCR on a representative sample of 70 tumor specimens. Analysis of 46 specimens from patients with clinical stages I and II detected 9 genes (MIR-124-1, MIR-124-3, MIR-125b-1, MIR-129-2, MIR-132, MIR-148a, MIR-193a, MIR-34b/c, and MIR-9-3), in which methylation was associated with the initial stages of the disease. Using ROC analysis, we formed two systems including 6 markers each and detecting breast cancer at stages I-II with high sensitivity (89 and 91%) and specificity (88%) at AUC=0.92-0.93. These sets were validated on the total sample of 70 specimens including all disease stages; they showed 93 and 94% sensitivities, 88% specificity, and AUC=0.95. Highly sensitive systems of markers, based on microRNA gene methylation, were created for the diagnosis of breast cancer at stages I-II.

Hypermethylated Genes of MicroRNA in Ovarian Carcinoma: Metastasis Prediction Marker Systems.

We identified a group of miRNA genes whose methylation is associated with ovarian cancer metastasis. Based on these data, new markers and the systems of markers predicting tumor dissemination were selected. Using methylation-specific PCR and a representative set of 54 ovarian cancer samples, we identified 10 microRNA genes (MIR-124a-2, MIR-127, MIR-125b-1, MIR-129-2, MIR-137, MIR-193a, MIR-203a, MIR-34b/c, MIR-130b, and MIR-1258) whose methylation is associated with tumor metastasis. The greatest association was established for 4 genes: MIR-137, MIR-193a, MIR-34b/c, and MIR-130b (p<0.01). ROC analysis revealed 3 most optimal marker systems including 4-5 miRNA genes and characterized by high sensitivity (82-94%) and specificity (76-86%) at AUC=0.89-0.92. Methylation of any three genes from these systems is sufficient to predict metastasis with the specified accuracy. Detection of the group of hypermethylated miRNA genes with predictive value for ovarian cancer metastasis is of great importance for personalized treatment of the patients.

Diagnostic Value of a Group of MicroRNA Genes Hypermethylated in Ovarian Carcinoma.

The study was designed to determine genes of microRNAs hypermethylated in malignant ovarian tumors and to select new diagnostic and prognostic markers of the disease and effective system of markers. Using methyl-specific PCR and a representative sample of 54 ovarian cancer specimens, we determined 5 microRNA genes (MIR-34b/c, MIR-9-1, MIR-124-3, MIR-129-2, and MIR-107) hypermethylated in the majority of tumor samples in comparison with paired samples of histologically unchanged tissue (48-57% vs. 4-19%, p<0.001). Using ROC-analysis, we selected an effective system of 4 markers for diagnosis of ovarian cancer (MIR-9-1, MIR-124-3, MIR-129-2, and MIR-107) characterized by high sensitivity and specificity (up to 87-94% at AUC=0.92) relative to the conventional norm (54 paired samples of histologically unchanged tissue) and absolute norm (18 ovarian tissue samples from subjects who died from non-tumor diseases). It was also shown that methylation of MIR-129-2, MIR-9-1, and MIR-34b/c genes is significantly (p<0.01) correlated with the clinical stage or the presence of metastases. The results indicate that epigenetic modifications of the studied microRNA genes are involved in the pathogenesis and progression of ovarian cancer and attest to their diagnostic and prognostic potential.

Five Hypermethylated MicroRNA Genes as Potential Markers of Ovarian Cancer.

MicroRNA and methylation are important epigenetic mechanisms in the pathogenesis of cancer. The role of a group of microRNA hypermethylated genes in the pathogenesis of ovarian cancer was studied and their diagnostic and prognostic potential was evaluated. Studies on a representative sample of 54 ovarian cancer specimens with the use of methyl-specific PCR resulted in detection of five microRNA genes (MIR-9-1, MIR-9-3, MIR-107, MIR-1258, and MIR-130b) methylated in the majority of tumor specimens in comparison with paired specimens of histologically intact tissue (37-57% vs. 4-9%, p<0.01). Methylation of three genes (MIR-9-1, MIR-9-3, and MIR-130b) was significantly (p≤0.05) associated with the parameters of ovarian cancer progress (clinical stage, differentiation degree, tumor size, and presence of metastases). These findings attest to oncosuppressive role of the studied microRNA genes (MIR-9-1, MIR-9-3, MIR-107, MIR-1258, and MIR-130b) in the pathogenesis and progress of ovarian cancer and indicated their prognostic potential.

Role of Methylation in the Regulation of Apoptosis Genes APAF1, DAPK1, and BCL2 in Breast Cancer.

Changes in the levels of expression of proapoptotic genes APAF1 and DAPK1 and antiapoptotic gene BCL2 were studied by real time PCR in specimens of tumors and histologically intact tissue from 28 patients with breast cancer. The expression of APAF1 and DAPK1 was below the normal in the majority of tumor samples (p<0.05), while the level of BCL2 mRNA more often surpassed the normal (p<0.1). Study of the same sample of specimens by methylspecific PCR showed predominance of APAF1 and DAPK1 hypermethylation (p<0.05 and p<0.1, respectively) and more frequent hypomethylation of BCL2. A significant correlation between changes in the levels of expression and methylation (r=0.40-0.49; p<0.05) was detected for all three genes (APAF1, DAPK1, and BCL2). The results suggest that methylation play an important role in the regulation of these apoptosis system genes in breast cancer.

[Clinical value of TNF, IL-6, and IL-10 gene polymorphic markers in chronic glomerulonephritis].

AIM: To study the association of the polymorphic markers (PMs) G(-238)A of the TNF gene, G(-174)C of the IL-6 gene, and G(-1082)A of the IL-10 gene with the clinical characteristics of chronic glomerulonephritis (CGN) and a response to immunosuppressive therapy (IST). SUBJECTS AND METHODS: Clinical syndromes at the time of diagnosis, the morphological types of nephritis, and a response to IST were analyzed in relation to the carriage of the examined PMs of the TNF, IL-6, and IL-10 genes in 102 patients with CGN. RESULTS: No association was found between the PM G(-238)A of the TNF gene and the clinical features of CGN. The carriers of the C allele of the PM G(-174) C of the IL-6 gene versus the homozygous individuals were observed to have more frequently kidney dysfunction at the time of diagnosis (р=0.014). Hypertension was more common in the carriers of the AA genotype of the PM G(-1082)A of the IL-10 gene (p=0.023); moreover, they tended to have a more frequent concurrence of nephrotic syndrome and hypertension (p=0.082). Analysis of the distribution of the morphological types of CGN disclosed that the proliferative variants were more common in the patients with the GG genotype (the TNF gene) as compared to the A allele carriers (p=0.067); and the nonproliferative forms were in the individuals homozygous for GG (the IL-6 gene) as compared to the C allele carriers (p=0.067). Examination of an IST response showed that a complete response at 12 months of treatment occurred more frequently in the carriers of the C allele of the IL-6 gene (p=0.045) and in those of the GG genotypes of the IL-10 gene (p=0.030). CONCLUSION: There was an association of the PMs G(-174)C of the IL-6 gene and G(-1082)A of the IL-10 gene with the clinical features of CGN and a response to IST.

[Association of CTLA4 and TNF gene polymorphisms with endocrine ophthalmopathy in ethnic Russian patients with Graves' disease]. / Assotsiatsiya polimorfnykh markerov genov CTLA4 i TNF s endokrinnoi oftal'mopatiei u patsientov russkogo proiskhozhdeniya s bolezn'yu Greivsa.

AIM: To analyze the associations of the rs3087243 CTLA4 polymorphism and the rs1800629 TNF polymorphism with endocrine ophthalmopathy (EOP) in ethnic Russian patients with Graves' disease (GD). MATERIAL AND METHODS: The case-control study enrolled 205 patients with GD. The distribution of alleles and genotypes of the rs3087243 CTLA4 and rs1800629 TNF polymorphisms was studied in 141 patients with GD and EOP (a GD+EOP group) and 64 patients with GD without EOP (a GD-EOP group). The polymorphic alleles were identified by polymerase chain reaction-restriction fragment length analysis. RESULTS: The patients with GD in their history and EOP had significantly higher frequencies of A allele and AA genotype and a lower proportion of G allele and GG genotype of the rs3087243 CTLA4 polymorphism. Comparative analysis revealed no significant differences in the frequency of the alleles and genotypes of the rs1800629 TNF polymorphism. CONCLUSION: The rs3087243 CTLA4 polymorphism is associated with the risk of EOP in ethnic Russian patients with GD.

[Association of the ABCB1 gene with risk for uveal melanoma].

The study investigated the association of the ABCB1 C3435T polymorphism gene with the risk for uveal melanoma (UM). Genotyping was carried out using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. All the tumors under study were histologically verified. The patients with UM were found to have a high frequency of predisposing alleles and genotypes of this polymorphism in the patients with UM. The CC genotype of the ABCB1 C3435T polymorphism was shown to be associated with the increased risk of UM (OR = 8.5; p = 7.10(-6)). A significant correlation was first found between the frequency of the CC genotype of the ABCB1 C3435T polymorphism and the height of a tumor and degree of its pigmentation (p = 0.0391 and p = 0.0381, respectively, Fisher's test). A marginal association was first shown between the CC genotype of the ABCB1 C3435T polymorphism and the vascular state and histological type.

[Association of polymorphic markers Arg72Pro of TP53 and T309g of MDM2 genes with non small cell lung cancer in Russians of Moscow region].

State Research Center "GosNIIgenetika", Moscow, 117545 Russia). Association of polymorphic markers Arg72Pro of TP53 gene and T309G of MDM2 gene with risk of non small cell lung cancer has been studied in Russians of Moscow region. We found an association of minor Pro/Pro genotype of polymorphic marker Arg72Pro (OR = 5.46, p = 8 x 10(-6)) and TG genotype of polymorphic marker T309G (OR = 5.57, p = 0.007) with non small cell lung cancer development. We have also showed a strong association of both Pro/Pro and TG genotypes with development of adenocarcinoma (OR = 8.71, p = 3 x 10(-6) and OR = 8.13, p = 0.003) and squamous-cell lung cancer (OR = 4.2, p = 0.001 and OR = 7.02, p = 0.002). We have finally found highly reliable association of combined susceptible genotypes of polymorphic markers Arg72Pro and T309G of TP53 and MDM2 genes with non small cell lung cancer and both its subtypes (OR = 7.9, p = 0.01; OR = 9.12,p = 0.02; OR = 7.31, p = 0.03, respectively).