Somatic point mutation calling in low cellularity tumors
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE47904 | GEO | 2014/06/13
SECONDARY ACCESSION(S): PRJNA209118
REPOSITORIES: GEO
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Project description:Illumina 1M Omni Quad arrays were used to test mutation calling accuracy of qSNP tool (a mutation caller) Ilumina array genotypes with GenCal (GC score)>0.70 were used in the comparison of genotype calls using next generation sequencing data and qSNP (mutation caller) 2 samples (control cell line and Melanoma cell line). This is the data for a validation step. contributor: Australian Pancreatic Cancer Genome Initiative
2014-06-13 | E-GEOD-47904 | biostudies-arrayexpress
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Project description:This is the validation data for candidate de novo CNV calls made in the CEU Hapmap by Itsara et al., Genome Research 2010. In this study, de novo CNV calls were initially made with Illumina 1M SNP arrays. Validation of CNV calls was performed with Nimblegen custom array CGH using the extended CEPH pedigrees. A truly de novo CNV would be unobserved in the first generation (CEU trio parents), validated in the second generation (CEU trio children), and assuming no selective effects, transmitted to approximately half of the individuals in the third generation. We attempted validation of 4 de novo CNVs in 3 extended CEPH pedigrees: 1358, 1408, and 1459.
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Project description:Somatic mutation calling from next-generation sequencing data remains a challenge due to the difficulties of distinguishing true somatic events from artifacts arising from PCR, sequencing errors or mis-mapping. Tumor cellularity or purity, sub-clonality and copy number changes also confound the identification of true somatic events against a background of germline variants. We have developed a heuristic strategy and software (http://www.qcmg.org/bioinformatics/qsnp/) for somatic mutation calling in samples with low tumor content and we show the superior sensitivity and precision of our approach using a previously sequenced cell line, a series of tumor/normal admixtures, and 3,253 putative somatic SNVs verified on an orthogonal platform.
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Project description:Hibernomas are benign tumors with morphological features resembling brown fat. They consistently display cytogenetic rearrangements, typically translocations, involving chromosome band 11q13. Here we demonstrate that these aberrations are associated with concomitant deletions of AIP and MEN1, tumor suppressor genes that are located 3 Mb apart and that underlie the hereditary syndromes pituitary adenoma predisposition and multiple endocrine neoplasia type I. MEN1 and AIP displayed a low expression in hibernomas whereas the expression of genes up-regulated in brown fat-PPARA, PPARG, PPARGC1A, and UCP1-was high. Thus, loss of MEN1 and AIP is likely to be pathogenetically essential for hibernoma development. Simultaneous loss of two tumor suppressor genes has not previously been shown to result from a neoplasia-associated translocation. Furthermore, in contrast to the prevailing assumption that benign tumors harbor relatively few genetic aberrations, the present analyses demonstrate that a considerable number of chromosome breaks are involved in the pathogenesis of hibernoma. Global copy number analysis was performed using single nucleotide polymorphism (SNP) array. Cases 1-14 were hybridized onto Illumina Human1M-Duo v3.0 (and Human CNV370-Quad v3.0) BeadChip (Illumina, San Diego, CA, USA), following standard protocols supplied by the manufacturer. Case 15 was analyzed using Illumina Human Omni-Quad BeadChip. Normal blood DNA was analyzed in cases 1, 2, 4 and 6 using the Human CNV370-Quad v3.0 BeadChip. Data analysis was done using the BeadStudio software (Illumina).
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Project description:High-resolution methods such as 4C and Capture-C enable the study of chromatin loops such as those formed between promoters and enhancers or CTCF/cohesin binding sites. An important aspect of 4C/CapC analyses is the identification of robust peaks in the data for the identification of chromatin loops. Here we present an R package for the analysis of 4C/CapC data. We generated 4C data for 10 viewpoints in 2 tissues in triplicate to test our methods. We developed a non-parametric peak caller based on rank-products. Sampling analysis shows that not read depth but template quality is the most important determinant of success in 4C experiments. By performing peak calling on single experiments we show that the peak calling results are similar to the replicate experiments, but that false positive rates are significantly reduced by performing replicates.
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Project description:This is the validation data for candidate de novo CNV calls made in the CEU Hapmap by Itsara et al., Genome Research 2010. In this study, de novo CNV calls were initially made with Illumina 1M SNP arrays. Validation of CNV calls was performed with Nimblegen custom array CGH using the extended CEPH pedigrees. A truly de novo CNV would be unobserved in the first generation (CEU trio parents), validated in the second generation (CEU trio children), and assuming no selective effects, transmitted to approximately half of the individuals in the third generation. We attempted validation of 4 de novo CNVs in 3 extended CEPH pedigrees: 1358, 1408, and 1459. 12 samples were hybridized in each of the three pedigrees (36 samples total) against a previously well-characterized reference (GM15510; see Tuzun et al., Nat Genet 2005).
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Project description:SNP profiles from 30 pheochromocytomas and paragangliomas were analyzed to detect identical-by-descent haplotypes, highlighting a founder mutation of SDHD in two samples. 30 pheochromocytomas and paragangliomas were analyzed with Illumina Human610-Quad v1.0 BeadChips.
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