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Träfflista för sökning "WFRF:(Sitaram Raviprakash T) "

Sökning: WFRF:(Sitaram Raviprakash T)

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1.
  • Machiela, Mitchell J., et al. (författare)
  • Genetic Variants Related to Longer Telomere Length are Associated with Increased Risk of Renal Cell Carcinoma
  • 2017
  • Ingår i: European Urology. - : Elsevier. - 0302-2838 .- 1873-7560. ; 72:5, s. 747-754
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Relative telomere length in peripheral blood leukocytes has been evaluated as a potential biomarker for renal cell carcinoma (RCC) risk in several studies, with conflicting findings.Objective: We performed an analysis of genetic variants associated with leukocyte telomere length to assess the relationship between telomere length and RCC risk using Mendelian randomization, an approach unaffected by biases from temporal variability and reverse causation that might have affected earlier investigations.Design, setting, and participants: Genotypes from nine telomere length-associated variants for 10 784 cases and 20 406 cancer-free controls from six genome-wide association studies (GWAS) of RCC were aggregated into a weighted genetic risk score (GRS) predictive of leukocyte telomere length.Outcome measurements and statistical analysis: Odds ratios (ORs) relating the GRS and RCC risk were computed in individual GWAS datasets and combined by meta-analysis.Results and limitations: Longer genetically inferred telomere length was associated with an increased risk of RCC (OR = 2.07 per predicted kilobase increase, 95% confidence interval [CI]: = 1.70-2.53, p < 0.0001). As a sensitivity analysis, we excluded two telomere length variants in linkage disequilibrium (R-2 > 0.5) with GWAS-identified RCC risk variants (rs10936599 and rs9420907) from the telomere length GRS; despite this exclusion, a statistically significant association between the GRS and RCC risk persisted (OR = 1.73, 95% CI = 1.36-2.21, p < 0.0001). Exploratory analyses for individual histologic subtypes suggested comparable associations with the telomere length GRS for clear cell (N = 5573, OR = 1.93, 95% CI = 1.50-2.49, p < 0.0001), papillary (N = 573, OR = 1.96, 95% CI = 1.01-3.81, p = 0.046), and chromophobe RCC (N = 203, OR = 2.37, 95% CI = 0.78-7.17, p = 0.13).Conclusions: Our investigation adds to the growing body of evidence indicating some aspect of longer telomere length is important for RCC risk.Patient summary: Telomeres are segments of DNA at chromosome ends that maintain chromosomal stability. Our study investigated the relationship between genetic variants associated with telomere length and renal cell carcinoma risk. We found evidence suggesting individuals with inherited predisposition to longer telomere length are at increased risk of developing renal cell carcinoma.
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2.
  • Scelo, Ghislaine, et al. (författare)
  • Genome-wide association study identifies multiple risk loci for renal cell carcinoma
  • 2017
  • Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723 .- 2041-1723. ; 8
  • Tidskriftsartikel (refereegranskat)abstract
    • Previous genome-wide association studies (GWAS) have identified six risk loci for renal cell carcinoma (RCC). We conducted a meta-analysis of two new scans of 5,198 cases and 7,331 controls together with four existing scans, totalling 10,784 cases and 20,406 controls of European ancestry. Twenty-four loci were tested in an additional 3,182 cases and 6,301 controls. We confirm the six known RCC risk loci and identify seven new loci at 1p32.3 (rs4381241, P = 3.1 x 10(-10)), 3p22.1 (rs67311347, P = 2.5 x 10(-8)), 3q26.2 (rs10936602, P = 8.8 x 10(-9)), 8p21.3 (rs2241261, P = 5.8 x 10(-9)), 10q24.33-q25.1 (rs11813268, P = 3.9 x 10(-8)), 11q22.3 (rs74911261, P = 2.1 x 10(-10)) and 14q24.2 (rs4903064, P = 2.2 x 10(-24)). Expression quantitative trait analyses suggest plausible candidate genes at these regions that may contribute to RCC susceptibility.
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3.
  • Laskar, Ruhina S, et al. (författare)
  • Sex specific associations in genome wide association analysis of renal cell carcinoma.
  • 2019
  • Ingår i: ; 27:10, s. 1589-1598
  • Tidskriftsartikel (refereegranskat)abstract
    • Renal cell carcinoma (RCC) has an undisputed genetic component and a stable 2:1 male to female sex ratio in its incidence across populations, suggesting possible sexual dimorphism in its genetic susceptibility. We conducted the first sex-specific genome-wide association analysis of RCC for men (3227 cases, 4916 controls) and women (1992 cases, 3095 controls) of European ancestry from two RCC genome-wide scans and replicated the top findings using an additional series of men (2261 cases, 5852 controls) and women (1399 cases, 1575 controls) from two independent cohorts of European origin. Our study confirmed sex-specific associations for two known RCC risk loci at 14q24.2 (DPF3) and 2p21(EPAS1). We also identified two additional suggestive male-specific loci at 6q24.3 (SAMD5, male odds ratio (ORmale) = 0.83 [95% CI = 0.78-0.89], Pmale = 1.71 × 10-8 compared with female odds ratio (ORfemale) = 0.98 [95% CI = 0.90-1.07], Pfemale = 0.68) and 12q23.3 (intergenic, ORmale = 0.75 [95% CI = 0.68-0.83], Pmale = 1.59 × 10-8 compared with ORfemale = 0.93 [95% CI = 0.82-1.06], Pfemale = 0.21) that attained genome-wide significance in the joint meta-analysis. Herein, we provide evidence of sex-specific associations in RCC genetic susceptibility and advocate the necessity of larger genetic and genomic studies to unravel the endogenous causes of sex bias in sexually dimorphic traits and diseases like RCC.
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5.
  • Johansson, Mattias, et al. (författare)
  • The influence of obesity-related factors in the etiology of renal cell carcinoma—A mendelian randomization study
  • 2019
  • Ingår i: ; 16:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Several obesity-related factors have been associated with renal cell carcinoma (RCC), but it is unclear which individual factors directly influence risk. We addressed this question using genetic markers as proxies for putative risk factors and evaluated their relation to RCC risk in a mendelian randomization (MR) framework. This methodology limits bias due to confounding and is not affected by reverse causation.Methods and findings: Genetic markers associated with obesity measures, blood pressure, lipids, type 2 diabetes, insulin, and glucose were initially identified as instrumental variables, and their association with RCC risk was subsequently evaluated in a genome-wide association study (GWAS) of 10,784 RCC patients and 20,406 control participants in a 2-sample MR framework. The effect on RCC risk was estimated by calculating odds ratios (ORSD) for a standard deviation (SD) increment in each risk factor. The MR analysis indicated that higher body mass index increases the risk of RCC (ORSD: 1.56, 95% confidence interval [CI] 1.44–1.70), with comparable results for waist-to-hip ratio (ORSD: 1.63, 95% CI 1.40–1.90) and body fat percentage (ORSD: 1.66, 95% CI 1.44–1.90). This analysis further indicated that higher fasting insulin (ORSD: 1.82, 95% CI 1.30–2.55) and diastolic blood pressure (DBP; ORSD: 1.28, 95% CI 1.11–1.47), but not systolic blood pressure (ORSD: 0.98, 95% CI 0.84–1.14), increase the risk for RCC. No association with RCC risk was seen for lipids, overall type 2 diabetes, or fasting glucose.Conclusions: This study provides novel evidence for an etiological role of insulin in RCC, as well as confirmatory evidence that obesity and DBP influence RCC risk.
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6.
  • Hosen, Ismail, et al. (författare)
  • TERT promoter mutations in clear cell renal cell carcinoma
  • 2015
  • Ingår i: International Journal of Cancer. - : John Wiley and Sons Inc.. - 0020-7136 .- 1097-0215. ; 136:10, s. 2448-2452
  • Tidskriftsartikel (refereegranskat)abstract
    • We screened promoter region of the telomerase reverse transcriptase (TERT) for activating somatic mutations in 188 tumors from patients with clear cell renal cell carcinoma (ccRCC). Twelve tumors (6.4%) carried a mutation within the core promoter region of the gene. The mutations were less frequent in high grade tumors compared to low grade tumors [odds ratio (OR)=0.15, 95% confidence interval (CI)=0.03-0.72, p=0.02]. Multivariate analysis for cause specific survival showed statistically significant poor outcome in patients with TERT promoter mutations [hazard ratio (HR)=2.90, 95% CI=1.13-7.39, p=0.03]. A common polymorphism (rs2853669) within the locus seemed to act as a modifier of the effect of the mutations on patient survival as the noncarriers of the variant allele with the TERT promoter mutations showed worst survival (HR=3.34, 95% CI=1.24-8.98, p=0.02). We also measured relative telomere length (RTL) in tumors and difference between tumors with and without the TERT promoter mutations was not statistically significant. Similarly, no difference in patient survival based on RTL in tumors was observed. Our study showed a relatively low frequency of TERT promoter mutations in ccRCC. Nevertheless, patients with the mutations, particularly in the absence of the rs2853669 variant showed the worst disease-specific survival. Thus, it is possible that the TERT promoter mutations define a small subset of tumors with an aggressive behavior. What's new? The human telomerase reverse transcriptase (TERT) gene encodes the catalytic subunit of telomerase, a ribonucleoprotein complex that maintains genomic integrity. Activating somatic mutations in the promoter region of the TERT gene have been reported in many cancers. Here, the authors describe new TERT promoter mutations in clear cell renal cell carcinoma. Although present only in a proportion of the tumors, the TERT promoter mutations were independently associated with poor patient survival. The effect was enhanced by a common polymorphism within the core TERT promoter. The TERT promoter mutations may thus define a small subset of tumors with an aggressive behavior.
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8.
  • Sitaram, Raviprakash T, 1974-, et al. (författare)
  • The PTEN regulator DJ-1 is associated with hTERT expression in clear cell renal cell carcinoma
  • 2009
  • Ingår i: International Journal of Cancer. - 0020-7136 .- 1097-0215. ; 125:4, s. 783-790
  • Tidskriftsartikel (refereegranskat)abstract
    • DJ-1 is as a novel regulator of the tumor suppressor PTEN with stimulatory effects on PI3K-AKT/PKB signaling, one possible target of which is cMyc. The catalytic unit of the telomerase complex, hTERT, can be activated at different levels, including transcriptionally by cMyc and through phosphorylation by AKT/PKB. The aim of the study was to analyze the putative signaling pathway encompassing DJ-1, cMyc and hTERT in a series of 176 renal cell carcinomas (RCC) and experimentally in cell lines. DJ-1 mRNA expression was significantly elevated in clear cell RCC (ccRCC) compared with in papillary RCC (pRCC; p = 0.005) and kidney cortex tissue (p < 0.001). ccRCC and pRCC demonstrated higher cMyc RNA levels than in kidney cortex (p < 0.001 for both) as well as increased levels of hTERT RNA (p < 0.001 and p = 0.011, respectively). DJ-1 was positively correlated to cMyc and hTERT in ccRCC (p < 0.001 and p = 0.019, respectively), but not in pRCC, indicating that this pathway could have a functional significance in ccRCC. siRNA knock down of DJ-1 induced downregulation of cMyc and hTERT mRNA associated with decreased expression of pAKT and cMyc protein levels. hTERT promoter activity was upregulated after DJ-1 transfection and this upregulation was inhibited after mutation of the cMyc binding sites. These experimental data support the functional link among DJ-1, cMyc and hTERT expression as indicated in the tumor material. Neither DJ-1, cMyc nor hTERT mRNA levels were associated with proliferation (S-phase fraction), telomere length or prognosis in ccRCC.
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9.
  • Sitaram, Raviprakash T, 1974-, et al. (författare)
  • Wilms' tumour 1 can suppress hTERT gene expression and telomerase activity in clear cell renal cell carcinoma via multiple pathways
  • 2010
  • Ingår i: British Journal of Cancer. - 0007-0920 .- 1532-1827. ; 103:8, s. 1255-1262
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Wilms' tumour 1 (WT1) gene was discovered as a tumour suppressor gene. Later findings have suggested that WT1 also can be oncogenic. This complexity is partly explained by the fact that WT1 has a number of target genes. METHOD: WT1 and its target gene human telomerase reverse transcriptase (hTERT) were analysed in clear cell renal cell carcinoma (ccRCC). In vitro experiments were performed to examine the functional link between WT1 and hTERT by overexpression of WT1 isoforms in the ccRCC cell line, TK-10. RESULTS: WT1 demonstrated lower RNA expression in ccRCC compared with renal cortical tissue, whereas hTERT was increased, showing a negative correlation between WT1 and hTERT (P=0.005). These findings were experimentally confirmed in vitro. The WT1 generated effect on hTERT promoter activity seemed complex, as several negative regulators of hTERT transcription, such as SMAD3, JUN (AP-1) and ETS1, were activated by WT1 overexpression. Downregulation of potential positive hTERT regulators, such as cMyc, AP-2α, AP-2γ, IRF1, NFX1 and GM-CSF, were also observed. Chromatin immunoprecipitation analysis verified WT1 binding to the hTERT, cMyc and SMAD3 promoters. CONCLUSION: The collected data strongly indicate multiple pathways for hTERT regulation by WT1 in ccRCC.
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10.
  • Svenson, Ulrika, et al. (författare)
  • Telomere length in relation to immunological parameters in patients with renal cell carcinoma
  • 2013
  • Ingår i: PLoS ONE. - : Public Library Science. - 1932-6203 .- 1932-6203. ; 8:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Over the last decade, telomere length (TL) has gained attention as a potential biomarker in cancer disease. We previously reported that long blood TL was associated with a poorer outcome in patients with breast cancer and renal cell carcinoma. Based on these findings, we hypothesized that certain immunological components may have an impact on TL dynamics in cancer patients. One aim of the present study was to investigate a possible association between serum cytokines and TL of peripheral blood cells, tumors and corresponding kidney cortex, in patients with clear cell renal cell carcinoma. For this purpose, a multiplex cytokine assay was used. Correlation analysis revealed significant positive correlations between tumor TL and peripheral levels of three cytokines (IL-7, IL-8 and IL-10). In a parallel patient group with various kidney tumors, TL was investigated in whole blood and in immune cell subsets in relation to peripheral levels of regulatory T cells (Tregs). A significant positive association was found between whole blood TL and Treg levels. However, the strongest correlation was found between Tregs and TL of the T lymphocyte fraction. Thus, patients with higher Treg levels displayed longer T cell telomeres, which might reflect a suppressed immune system with fewer cell divisions and hence less telomere shortening. These results are in line with our earlier observation that long blood TL is an unfavorable prognostic factor for cancer-specific survival. In summary, we here show that immunological components are associated with TL in patients with renal cell carcinoma, providing further insight into the field of telomere biology in cancer. 
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