Unknown,Transcriptomics,Genomics,Proteomics

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Genomic aberrations predicts survival in clear cell renal cell carcinoma

ABSTRACT: Detailed genetic profiling of clear cell Renal Cell Carcinoma (ccRCC) has shown that these tumors are characterized by large genetic heterogeneity with some genomic regions commonly affected by structural changes. Loss on chromosomes 3p and 14q, and gain on 5q and 7 are examples of alterations commonly reported in ccRCC. However, there is no consensus regarding the potential prognostic information carried by the identified alterations. We report on poorer outcome for patients with gain on 5q and 7, and loss on 9p, 9q and 14q. These aberrations were in addition found more frequently in metastasized tumors, suggesting that they are markers for advanced disease. Furthermore, the presence of M-bM-^IM-% 4 common aberrations was associated with decreased survival time. Shorter relative telomere length (RTL) has been associated with loss of chromosomal regions in ccRCC tumors, but we found no significant associations between tumor RTL and chromosomal deletions. However, significantly lower tumor-to-nontumor (T/N) RTL ratio was detected for patients with loss on 4q and 9p. Finally, we found a minimum region (MR) of genetic loss of 1.4 Mbp on chromosome 9p and this region contains only one gene, the tumor suppressor candidate 1 gene (TUSC1). TUSC1 has been implicated in lung carcinogenesis and our result further strengthens its role in tumorigenesis. Seventy-four ccRCC tumors and 22 paired normal kidney cortex and blood samples were genotyped on Illuminas HumanCytoSNP-12 bead chips.

ORGANISM(S): Homo sapiens

SUBMITTER: Linda KM-CM-6hn

PROVIDER: E-GEOD-30460 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Sakha M-bM-^@M-^S an area connecting South and Northeast Siberia M-bM-^@M-^S is significant for understanding the history of peopling of Northeast Eurasia and the Americas. Previous studies have shown a genetic contiguity between Siberia and East Asia and the key role of South Siberia in the colonization of Siberia. We report the results of a high-resolution phylogenetic analysis of 701 mtDNAs and 318 Y chromosomes from five native populations of Sakha (Yakuts, Evenks, Evens, Yukaghirs and Dolgans) and of the analysis of more than 500,000 autosomal SNPs of 758 individuals from 55 populations, including 40 previously unpublished samples from Siberia. Phylogenetically terminal clades of East Asian mtDNA haplogroups C and D and Y-chromosome haplogroups N1c, N1b and C3, constituting the core of the gene pool of the native populations from Sakha, connect Sakha and South Siberia. Analysis of autosomal SNP data confirms the genetic continuity between Sakha and South Siberia. Maternal lineages D5a2a2, C4a1c, C4a2, C5b1b and the Yakut-specific STR sub-clade of Y-chromosome haplogroup N1c can be linked to a migration of Yakut ancestors, while the paternal lineage C3c was most likely carried to Sakha by the expansion of the Tungusic people. MtDNA haplogroups Z1a1b and Z1a3, present in Yukaghirs, Evens and Dolgans, show traces of different and probably more ancient migration(s). Analysis of both haploid loci and autosomal SNP data revealed only minor genetic components shared between Sakha and the extreme Northeast Siberia. Although the major part of West Eurasian maternal and paternal lineages in Sakha could originate from recent admixture with East Europeans, mtDNA haplogroups H8, H20a and HV1a1a, as well as Y-chromosome haplogroup J, more probably reflect an ancient gene flow from West Eurasia through Central Asia and South Siberia. Our high-resolution phylogenetic dissection of mtDNA and Y-chromosome haplogroups as well as analysis of autosomal SNP data suggests that Sakha was colonized by repeated expansions from South Siberia with minor gene flow from the Lower Amur/Southern Okhotsk region and/or Kamchatka. The minor West Eurasian component in Sakha attests to both recent and ongoing admixture with East Europeans and an ancient gene flow from West Eurasia. 40 samples were analysed with the Illumina platform Human660W-Quad v1.0 and are described herein.

Project description:Illumina Infinium whole genome genotyping (WGG) arrays are increasingly being applied in cancer genomics to study gene copy number alterations and allele-specific aberrations such as loss-of-heterozygosity (LOH). Methods developed for normalization of WGG arrays have mostly focused on diploid, normal samples. However, for cancer samples genomic aberrations may confound normalization and data interpretation. Therefore, we examined the effects of the conventionally used normalization method for Illumina Infinium arrays when applied to cancer samples. We demonstrate an asymmetry in the detection of the two alleles for each SNP, which deleteriously influences both allelic proportions and copy number estimates. The asymmetry is caused by a remaining bias between the two dyes used in the Infinium II assay after using the normalization method in Illumina’s proprietary software (BeadStudio). We propose a quantile normalization strategy for correction of this dye bias. We tested the normalization strategy using 535 individual hybridizations from 10 data sets from the analysis of cancer genomes and normal blood samples generated on Illumina Infinium II 300k version 1 and 2, 370k and 550k BeadChips. We show that the proposed normalization strategy successfully removes asymmetry in estimates of both allelic proportions and copy numbers. Additionally, the normalization strategy reduces the technical variation for copy number estimates while retaining the response to copy number alterations. The proposed normalization strategy represents a valuable low-level analysis tool that improves the quality of data obtained from Illumina Infinium arrays, in particular when used for LOH and copy number variation studies. To investigate the effects of a quantile normalization of Illumina Infinium data, compared to conventional normalization using BeadStudio (www.illumina.com), we renormalized 535 individual hybridizations conducted on Illumina 300K, 370K and 550K BeadChips. Sample types included breast cancer, colon cancer, urothelial carcinoma, leukemia as well as normal blood and HapMap samples. This series includes the 6 breast cancers hybridized on Illumina HumanHap 550K BeadChips.

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Genomic aberrations predicts survival in clear cell renal cell carcinoma

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