Project description:Genetic variation amongst individual humans occurs on many different scales, ranging from gross alterations in the human karyotype to single-nucleotide changes. In this manuscript we explore variation on an intermediate scale-particularly insertions, deletions, and inversions affecting from a few thousand to a few million base pairs. We employed a clone-based method to interrogate this intermediate structural variation in eight individuals of diverse geographic ancestry. Our analysis provides a comprehensive overview of the normal pattern of structural variation present in these genomes, refining the location of 1695 structural variants. We find that 50% were seen in more than one individual and that nearly half lay outside regions of the genome previously described as structurally variant. We discover 525 new insertion sequences that are not present in the human reference genome and show that many of these are variable in copy number among individuals. Sequencing of a subset of structural variants reveals considerable locus complexity and provides insights into the different mutational processes that have shaped the human genome. These data provide the first high-resolution sequence-map of human structural variation-an important standard for genotyping platforms and a prelude to future individual genome sequencing projects. Keywords: comparative genomic hybridization The DNA samples are a panel of 8 Hapmap samples, described by E. Eichler et al. (2007, Nature 447, 161-165). This set of 7 female, and one male samples are from from the Coriell Cell Repository, and is comprised of samples from four populations: four Yoruban, two CEPH, one Chinese, and one Japanese. The reference sample, NA15510, is female and also from the Corriel Cell Repository. This sample has been extensively characterized, (for example in Tuzan et al. 2005, Nature Genetics 10, p1038) and has been recommended for use in CNV detection programs to allow meaningful comparison of data between studies (discussed in Scherer, et al. 2007, Nature Genetics Supplement 39: S7-S15). Each of these samples was hybridized in pairs with the reversed labeling polarities. Additionally, 3 self-self control hybridizations were carried out for the reference sample, NA15510, one on each hybridization date.

Project description:We used microarrays to identify the variation of basal gene expression level among 287 lymphoblastoid cell lines. Radiation therapy is used to treat half of all cancer patients. Response to radiation therapy varies widely among patients. Therefore, we performed a genome-wide association study (GWAS) to identify biomarkers to help predict radiation response using 277 ethnically defined human lymphoblastoid cell lines (LCLs). Basal gene expression levels and 1.3 million genome-wide SNP markers from both Affymetrix and Illumina platforms were assayed for all 277 human LCLs. MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assays for radiation cytotoxicity were also performed to obtain area under the curve (AUC) as a radiation response phenotype for use in the association studies. Functional validation of candidate genes, selected from an integrated analysis that used SNP, expression and AUC data, was performed with multiple cancer cell lines using specific siRNA knockdown, followed by MTS and colony-forming assays. 27 loci, each containing at least 2 SNPs within 50kb with p-values <10-4, were associated with radiation AUC. 270 expression probe sets were associated with radiation AUC with p<10-3. The integrated analysis identified 50 SNPs in 14 of the 27 loci that were associated with both AUC and the expression of 39 genes that were also associated with radiation AUC (p<10-3). Functional validation using siRNA knockdown in multiple tumor cell lines showed that C13orf34, MAD2L1, PLK4, TPD52 and DEPDC1B each significantly altered radiation sensitivity in at least 2 cancer cell lines. Studies performed with LCLs can help to identify novel biomarkers that might contribute to variation in response to radiation therapy and enhance our understanding of mechanisms underlying that variation. EBV-transformed LCLs from 95 African-American (AA), 96 Caucasian-American (CA), and 96 Han Chinese-American (HCA) unrelated healthy subjects (sample sets HD100AA, HD100CAU, HD100CHI) were purchased from the Coriell Cell Repository (Camden, NJ).

Project description:Low grade flat ductal intraepithelial neoplasia (DIN1a, flat epithelial atypia) is one of the earliest morphologically recognizable neoplastic lesions of the breast. Frequently, it occurs in association with lobular intraepithelial neoplasia (LIN). The aim of this study was to elucidate chromosomal aberrations in these early neoplastic breast lesions using array comparative genomic hybridization (CGH) analysis. Laser capture microdissection of 12 archival formalin-fixed, paraffin-embedded specimens harbouring both foci of DIN1a as well as LIN was performed. All analyzed cases of DIN1a and LIN showed chromosomal gains and losses. The aberration encountered most often was loss on 16q in 7 DIN1a (70%) and 10 LIN (91%) cases. Regarding changes in chromosome 1, four DIN1a (40%) and 7 LIN (64%) cases showed a gain on 1q. The results of our study show concurrent chromosomal aberrations of 1q gains and 16q losses in several cases with coexisting LIN and low grade flat DIN. These aberrations are known to be common in low grade invasive ductal carcinomas as well as more advanced (conventional) types of low grade DIN (low grade ductal carcinoma in-situ). Our results raise the possibility of similar molecular-genetic pathways in most of the cases with coexisting LIN and low grade flat DIN. In this study, 11 cases of classic lobular intraepithelial neoplasias and 10 cases with several areas of low grade flat DIN (DIN1a or flat epithelial atypia) were analyzed by array CGH. Sections of formalin-fixed paraffin-embedded (FFPE) specimens cut at 7-8µm were mounted on special foil-coated slides (Molecular Devices, San Diego, USA). The sections were then deparaffinized with Xylene, processed in decreasing concentrations of ethanol and stained with haematoxylin. Lasercapture microdissection for both lesions was performed at multiple sites using Veritas Arcturus. For reference-DNA, female mammary tissue without histomorphological changes obtained from reduction mammoplasty specimens was procecessed and laser-microdissected as explained above. Cells were digested in 10µl TE, pH 9, and 0.5µl proteinase K (20mg/ml) for 48h at 55°C. After inactivation of proteinase K at 99°C for 10min, the digest was stored at -20°C. Without any further purification, the complete digest was used for whole genome amplification by means of the WGA (Whole Genome Amplification) kit from Sigma following the manufacturer’s recommendations. Array CGH was performed as described previously. In brief, two µg of amplified tumor and reference DNA were labelled by random priming (BioPrime® Total Genomic Labeling System, Invitrogen, Carlsbad, CA) with Alexa Fluor® 3 and Alexa Fluor® 5, respectively, and hybridized onto a tiling path BAC array, consisting of the human 32k BAC Re-Array Set (BACPAC Resources Center; http://bacpac.chori.org/pHumanMinSet.htm; DNA kindly provided by Pieter de Jong) and a 1Mb Resolution BAC set (clones kindly provided by Nigel Carter, Wellcome Trust Sanger Centre). All protocols are provided in detail on our website (http://www.molgen.mpg.de/~abt_rop/molecular_cytogenetics/) and more information concerning this platform have been submitted to the Gene Expression Omnibus (GEO; http://www.ncbi.nlm.nih.gov/geo/; GPL5114). For the analysis and visualization of array CGH data, our software-package CGH-PRO was employed. No background subtraction was applied. Raw data were normalized by “Subgrid LOWESS”. For the assessment of copy number gains and losses, we used circular binary segmentation in combination with log2 ratio thresholds of 0.15 and -0.15, respectively.

Project description:Lobular intraepithelial neoplasia grade 3 (LIN) is a recently recognized variant of intraepithelial lobular neoplasia of the breast composed of either uniform, generally small, cells (classic) with massive lobular distension, pleomorphic cells, signet-ring cells, or any cell type with necrosis. In contrast to classic forms of LIN, there is no consensus on therapeutic strategies for LIN3. In part this is due to the paucity of molecular data that could assist in defining the relationship of LIN3 to classic LIN and carcinomas. In this study we have employed array CGH to determine the patterns of chromosomal aberrations in 9 LIN3 lesions. By comparison to array CGH data of 13 classic LIN lesions, we demonstrate that LIN and LIN3 share several recurrent changes, in particular gains of 1q and losses of 16q. Both aberrations are known to appear early in tumorigenesis and to be associated with good prognosis. However, apart from this overlap, there were a number of karyotypic features that were observed exclusively in LIN3. Clearly, this lesion was characterized by a significantly higher number of DNA copy number changes (9 vs. 31 on average), a considerable complexity of chromosomal rearrangements with up to 16 breakpoints in one chromosome and overlapping high copy amplifications. The amplicons encompassed a number of known oncogenes such as ERBB2, CyclinD1 and FGF3 that have already been reported to be overexpressed in breast carcinomas. Our data suggest that, at the genetic level, LIN3 represents a highly advanced lesion with considerable resemblance to carcinomas and, therefore, reflects a lesion on the verge of invasion, and might represent the transition state from an intraepithelial neoplasm to breast carcinoma. In this study, nine cases of pleomorphic/necrotic LIN lesions as well as one classic LIN and the concurrent invasive lobular carcinoma (ILC) were analyzed by array CGH. Sections of formalin-fixed paraffin-embedded (FFPE) specimens cut at 7-8Âµm were mounted on special foil-coated slides (Molecular Devices, San Diego, USA). The sections were then deparaffinized with Xylene, processed in decreasing concentrations of ethanol and stained with haematoxylin. Lasercapture microdissection for both lesions was performed at multiple sites using Veritas Arcturus. For reference-DNA, female mammary tissue without histomorphological changes obtained from reduction mammoplasty specimens was procecessed and laser-microdissected as explained above. Cells were digested in 10Âµl TE, pH 9, and 0.5Âµl proteinase K (20mg/ml) for 48h at 55Â°C. After inactivation of proteinase K at 99Â°C for 10min, the digest was stored at -20Â°C. Without any further purification, the complete digest was used for whole genome amplification by means of the WGA (Whole Genome Amplification) kit from Sigma following the manufacturerâs recommendations. Array CGH was performed as described previously. In brief, two Âµg of amplified tumor and reference DNA were labelled by random priming (BioPrimeÂ® Total Genomic Labeling System, Invitrogen, Carlsbad, CA) with Alexa FluorÂ® 3 and Alexa FluorÂ® 5, respectively, and hybridized onto a tiling path BAC array, consisting of the human 32k BAC Re-Array Set (BACPAC Resources Center; http://bacpac.chori.org/pHumanMinSet.htm; DNA kindly provided by Pieter de Jong) and a 1Mb Resolution BAC set (clones kindly provided by Nigel Carter, Wellcome Trust Sanger Centre). All protocols are provided in detail on our website (http://www.molgen.mpg.de/~abt_rop/molecular_cytogenetics/) and more information concerning this platform have been submitted to the Gene Expression Omnibus (GEO; http://www.ncbi.nlm.nih.gov/geo/; GLP: 5114). For the analysis and visualization of array CGH data, our software-package CGH-PRO was employed. No background subtraction was applied. Raw data were normalized by âSubgrid LOWESSâ. For the assessment of copy number gains and losses, we used circular binary segmentation in combination with log2 ratio thresholds of 0.15 and -0.15, respectively. High copy amplifications were defined by focal appearance and a log2 ratio exceeding 0.45. In order to statistically investigate the similarity of aberration profiles we applied Pearson's product-moment correlation to cbs ratios of each of the corresponding arrays.

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1000 Genomes Phase 3 aCGH samples

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