Genotyping by array of human primary acute myeloid leukemia cells on the Affymetrix 6.0 SNP array to evaluate prognostic relevance
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ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Meyling Cheok
PROVIDER: E-MTAB-1586 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:The TET2 locus was analyzed for DNA copy number, and LOH using a large set of paired samples (n=106), i.e. AML cells at diagnosis and normal peripheral blood mononuclear cells at remission; and AML at diagnosis (n=6). Affymetrix 6.0 SNP array were used.
2010-06-01 | E-MTAB-278 | biostudies-arrayexpress
Project description:BACKGROUND: Genome-wide association studies (GWAS) using array-based genotyping technology are widely used to identify genetic loci associated with complex diseases or other phenotypes. The costs of GWAS projects based on individual genotyping are still comparatively high and increase with the size of study populations. Genotyping using pooled DNA samples, as also being referred as to allelotyping approach, offers an alternative at affordable costs. In the present study, data from 100 DNA samples individually genotyped with the Affymetrix Genome-Wide Human SNP Array 6.0 were used to estimate the error of the pooling approach by comparing the results with those obtained using the same array type but DNA pools each composed of 50 of the same samples. Newly developed and established methods for signal intensity correction were applied. Furthermore, the relative allele intensity signals (RAS) obtained by allelotyping were compared to the corresponding values derived from individual genotyping. Similarly, differences in RAS values between pools were determined and compared. RESULTS: Regardless of the intensity correction method applied, the pooling-specific error of the pool intensity values was larger for single pools than for the comparison of the intensity values of two pools, which reflects the scenario of a case-control study. Using 50 pooled samples and analyzing 10,000 SNPs with a minor allele frequency of >1% and applying the best correction method for the corresponding type of comparison, the 90% quantile (median) of the pooling-specific absolute error of the RAS values for single sub-pools and the SNP-specific difference in allele frequency comparing two pools was 0.064 (0.026) and 0.056 (0.021), respectively. CONCLUSIONS: Correction of the RAS values reduced the error of the RAS values when analyzing single pool intensities. We developed a new correction method with high accuracy but low computational costs. Correction of RAS, however, only marginally reduced the error of true differences between two sample groups and those obtained by allelotyping. Exclusion of SNPs with a minor allele frequency of ? 1% notably reduced the pooling-specific error. Our findings allow for improving the estimation of the pooling-specific error and may help in designing allelotyping studies using the Affymetrix Genome-Wide Human SNP Array 6.0.
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Project description:Pluripotent human embryonic stem cells are studied for potential applications in regenerative cell replacement therapies because of their untransformed nature and unique capacity to self-renew and differentiate. However it is known that adaptation of hESCs occurs on prolonged culture and may be associated with the acquisition of chromosome abnormalities. We report a high resolution DNA SNP 6.0 array analysis showing copy number variation in 17 different hESC lines maintained in different laboratories. Several of the changes were culture induced and changed the expression levels of affected genes. Loss of heterozygosity (LOH) of chromosome 16q was detected in one line, in addition to several smaller LOH regions. Importantly, hESCs were found to contain several CNVs less than 3 Mb in size which is below the detection limit of conventional karyotyping.
2010-03-01 | GSE15096 | GEO
Project description:Copy number analysis can be useful for assessing prognosis in diffuse large B cell lymphoma (DLBCL). We analyzed copy number data from tumor samples of 60 patients diagnosed with DLBCL de novo and their matched normal samples. We detected a total of 63 recurrent copy number alterations (CNAs), including 33 gains, 30 losses, and nine recurrent acquired copy number neutral loss of heterozygosity (CNN-LOH). Interestingly, 20% of cases acquired CNN-LOH of 6p21 locus, which involves the HLA region. In normal cells there were no CNAs but we observed CNN-LOH involving some key lymphoma regions such as 6p21 and 9p24.1 (5%) and 17p13.1 (2.5%) in DLBCL patients. Furthermore, a model with some specific CNA was able to predict the subtype of DLBCL, 1p36.32 and 10q23.31 losses being restricted to germinal center B cell-like (GCB) DLBCL. In contrast, 8p23.3 losses and 11q24.3 gains were strongly associated with the non-GCB subtype. A poor prognosis was associated with biallelic inactivation of TP53 or 18p11.32 losses, while prognosis was better in cases carrying 11q24.3 gains, which includes ETS1 and FLI1 genes. In summary, CNA abnormalities identify specific DLBCL groups, and we describe CN-LOH in germline cells from DLBCL patients that are associated with genes that probably play a key role in DLBCL development.
2016-01-22 | GSE71389 | GEO
Project description:Chordomas are rare, low to intermediate grade malignant bone tumors of the axial skeleton, believed to originate from the notochord. Treatment options are limited and mainly restricted to surgical excision, as chordomas have been proven to be largely resistant to conventional ionizing radiation and chemotherapy. Therefore a new cell line was established. The cell line has been characterized by immunohistochemistry,western blot and karyotyping using cobra fish technology. Copy number variations (CNV) and loss-of heterozygosity (LOH) from fibroblasts, tumor tissue, low and high cell line passage was evaluted by using Affymetrix 6.0SNP Arrays. DNA isolated from the patients MNCs was used as control. The cell line MUG-Chor1 is highly similar to genetic profiles of chordomas and provides therefore a powerful tool for further investigations.
2012-07-12 | GSE25720 | GEO
Project description:To determine if the at-risk single-nucleotide polymorphism (SNP) alleles for colorectal cancer (CRC) could contribute to clinical situations suggestive of an increased genetic risk for CRC, we performed a prospective national case-control study based on highly selected patients (CRC in two first-degree relatives, one before 61 years of age; or CRC diagnosed before 51 years of age; or multiple primary CRCs, the first before 61 years of age; exclusion of Lynch syndrome and polyposes) and controls without personal or familial history of CRC. SNPs were genotyped using SNaPshot, and statistical analyses were performed using Pearson's χ(2) test, Cochran-Armitage test of trend and logistic regression. We included 1029 patients and 350 controls. We confirmed the association of CRC risk with four SNPs, with odds ratio (OR) higher than previously reported: rs16892766 on 8q23.3 (OR: 1.88, 95% confidence interval (CI): 1.30-2.72; P=0.0007); rs4779584 on 15q13.3 (OR: 1.42, CI: 1.11-1.83; P=0.0061) and rs4939827 and rs58920878/Novel 1 on 18q21.1 (OR: 1.49, CI: 1.13-1.98; P=0.007 and OR: 1.49, CI: 1.14-1.95; P=0.0035). We found a significant (P<0.0001) cumulative effect of the at-risk alleles or genotypes with OR at 1.62 (CI: 1.10-2.37), 2.09 (CI: 1.43-3.07), 2.87 (CI: 1.76-4.70) and 3.88 (CI: 1.72-8.76) for 1, 2, 3 and at least 4 at-risk alleles, respectively, and OR at 1.71 (CI: 1.18-2.46), 2.29 (CI: 1.55-3.38) and 6.21 (CI: 2.67-14.42) for 1, 2 and 3 at-risk genotypes, respectively. Combination of SNPs may therefore explain a fraction of clinical situations suggestive of an increased risk for CRC.
| S-EPMC4795220 | biostudies-literature
Project description:Pluripotent human embryonic stem cells are studied for potential applications in regenerative cell replacement therapies because of their untransformed nature and unique capacity to self-renew and differentiate. However it is known that adaptation of hESCs occurs on prolonged culture and may be associated with the acquisition of chromosome abnormalities. We report a high resolution DNA SNP 6.0 array analysis showing copy number variation in 17 different hESC lines maintained in different laboratories. Several of the changes were culture induced and changed the expression levels of affected genes. Loss of heterozygosity (LOH) of chromosome 16q was detected in one line, in addition to several smaller LOH regions. Importantly, hESCs were found to contain several CNVs less than 3 Mb in size which is below the detection limit of conventional karyotyping. Copy number analysis of Affymetrix SNP 6.0 arrays was performed for 29 hESC samples of various passages and laboratory origin. 40 reference HapMap samples from Affymetrix were hybridized at the same time to built a reference genome used in the analysis.
2010-03-01 | E-GEOD-15096 | biostudies-arrayexpress
Project description:Copy number and LOH analysis was performed for 56 chronic myeloid leukemia cases obtained from 23 CML cases obtained atchronic phase, accelerated phase, blast crisis, or remission. All caseswere genotyped with Affymetrix 250k Sty and Nsp arrays. Keywords: Acute leukemia, BCR-ABL1, chronic myeloid leukemia, copy number analysis, loss-of-heterozygosity, genomics *** Due to privacy concerns, the primary SNP array data is no longer available with unrestricted access. Individuals wishing to obtain this data for research purposes may request access using the Web links below. ***
2009-09-02 | GSE9110 | GEO
Project description:Generating sufficient DNA for high-throughput genetic analysis has always been a challenge for clinical settings where the amount of source DNA is limited. Multiple displacement amplification (MDA) has been proposed as a promising candidate for such situations. Previous work with lower-resolution arrays confirmed the utility of single-cell MDA products for large-size (~30 Mb) genome variation screening. We tested the performance of single-cell MDA products on the SNP 6.0 arrays to examine the performance of single-cell MDA in SNP genotyping, copy number polymorphism, de novo copy number variation (CNV) and loss of heterozygosity (LOH) analysis. Our data show that for SNP genotyping, single-cell MDA did not obtain complete genome coverage or high sequence fidelity. For CNV calling, single-cell MDA introduced stochastic amplification artifacts in log2 ratio profiles, reducing the robustness of CNV calling; however, by adjusting smooth window size, it is still possible to analyze large chromosomal aberrations, and homozygous deletions as small as 500 kb can still be identified from the noisy log2 ratio profiles. Our results also suggest that even with a modified protocol (reduction of reaction volume, addition of a molecular crowding reagent, minimization of reaction time), single-cell MDA presented little improvement over the unmodified protocol, but by increasing the number of cells as template to 5–10 cells, SNP 6.0 array results comparable to those of 10 ng genomic DNA MDA could be obtained. Algorithms like PICNIC improved the CNV calling, suggesting that better algorithms can better utilize single-cell MDA array results.
2011-03-25 | GSE28132 | GEO
Project description:Chordomas are rare, low to intermediate grade malignant bone tumors of the axial skeleton, believed to originate from the notochord. Treatment options are limited and mainly restricted to surgical excision, as chordomas have been proven to be largely resistant to conventional ionizing radiation and chemotherapy. Therefore a new cell line was established. The cell line has been characterized by immunohistochemistry,western blot and karyotyping using cobra fish technology. Copy number variations (CNV) and loss-of heterozygosity (LOH) from fibroblasts, tumor tissue, low and high cell line passage was evaluted by using Affymetrix 6.0SNP Arrays. DNA isolated from the patients MNCs was used as control. The cell line MUG-Chor1 is highly similar to genetic profiles of chordomas and provides therefore a powerful tool for further investigations. Affymetrix SNP 6.0 arrays were performed according to the manufacturer's directions on DNA extracted from cryo material or cell lines. Copy number analysis of Affymetrix SNP 6.0 arrays was performed for 4 samples. 60 samples from HapMap database were used as references for copy number inference.
2012-07-11 | E-GEOD-25720 | biostudies-arrayexpress