Project description:Chromosomal regions harboring tumor suppressors and oncogenes are often deleted or amplified. Array comparative genomic hybridization (CGH) detects segmental DNA copy number alterations in tumor DNA relative to a normal control. The recent development of a bacterial artificial chromosome (BAC) array, that spans the human genome in a tiling path manner with >32,000 clones, has facilitated whole genome profiling at an unprecedented resolution. Using this technology, we comprehensively describe and compare the genomes of 28 commonly used non-small cell lung carcinoma cell models, derived from 18 adenocarcinomas, 9 squamous cell carcinomas, and 1 large cell carcinoma. Analysis at such resolution not only provided a detailed genomic alteration template for each of these model cell lines, but revealed novel regions of frequent duplication and deletion. Significantly, a detailed analysis of chromosome 7 identified 6 distinct regions of alterations across this chromosome implicating the presence of multiple novel oncogene loci on this chromosome. As well, a comparison between the squamous and adenocarcinoma cells revealed alterations common to both subtypes, such as the loss of 3p and gain of 5p, in addition to multiple hotspots more frequently associated with only one subtype. Interestingly, chromosome 3q, which is known to be amplified in both subtypes, showed two distinct regions of alteration, one frequently altered in squamous and one more frequent altered in adenocarcinoma. In summary, our data demonstrates the unique information generated by high resolution analysis of NSCLC genomes and uncovers the presence of genetic alterations prevalent in the different NSCLC subtypes. Keywords: array CGH, amplification, segmental copy number, NSCLC, Lung cancer, genetic alterations
Project description:Co-amplification at chromosomes 8p11-8p12 and 11q12-11q14 occurs often in breast tumors, suggesting possible cooperation between genes in these regions in oncogenesis. We used high resolution array comparative genomic hybridization (array CGH) to map the minimal amplified regions. The 8p and 11q amplicons are complex and consist of at least four amplicon cores at each site. Candidate genes mapping to these regions were identified by combining copy number and RNA and protein expression analyses. Funcational analysis for transformation was further carried out with candidate genes to determine candidate oncogenes. Near tiling path coverage of 8p11q array CGH experiments with breast cell lines and ductal invasive and lymph node-negative breast tumors.
Project description:Cervical cancer is the second most common malignancy in women worldwide, with high risk subtypes of human papillomavirus (HPV) constituting the major etiological agent. However, only a small percentage of women infected by the virus develop disease suggesting that additional host genetic alterations are necessary for disease progression. In this study we examined the genomes of a panel of commonly used model cervical cancer cell lines using a recently developed whole genome tiling path array for CGH analysis. Detailed analysis of genomic profiles enabled the detection of many novel aberrations which may have been missed by conventional cytogenetic methods. In total, 27 minimal regions of recurrent copy number alteration were identified that are potentially involved in tumorigenesis. Interestingly, fine mapping of the 3q gain, which is associated with the progression of precursor lesions to invasive cervical cancer, identified a minimal region of alteration harboring genes distinct from previous candidates. Novel regions of gene amplification, including the co-amplification of both the Birc and MMP gene clusters on 11q22, were also evident. Lastly, characterization of genomic structure at sites of HPV integration identified the copy number gain of host cellular sequences between the viral-host genomic boundaries in both SiHa and SW756, suggesting a direct role for HPV integration in the development of genetic abnormalities that initiate cervical cancer. This work represents the highest resolution look at a cervical cancer genome to date and offers definitive characterization of the alteration status of these cancer genomes. Whole genome tiling path array CGH profiles of 8 Cervical Cancer Cell Lines
Project description:Deletions and amplifications of the human genomic sequence (Copy Number Polymorphisms, or 'CNPs') are the cause for numerous diseases and a potential cause of phenotypic variation in the normal population. Comparative Genomic Hybridization (CGH) has been developed as a useful tool for detecting alterations in DNA copy number that involve blocks of DNA several kilobases or greater in size. We have developed High-Resolution CGH (HR-CGH) to detect accurately and with relatively little bias the presence and extent of chromosomal aberrations in human DNA. Maskless array synthesis was used to construct arrays containing 393,000 oligonucleotides with isothermal probes of 45-85 bp in length; arrays tiling the β-globin locus and chromosome 22q were prepared. Arrays with 9 bp tiling path were used to map a 622 bp heterozygous deletion in the β-globin locus. Arrays with an 85 bp tiling path were used to analyze DNA from patients with copy number changes in the pericentromeric region of chromosome 22. Heterozygous deletions and duplications as well as partial triploidies and partial tetraploidies of portions of chromosome 22q were mapped with high resolution in each patient, and the precise breakpoint of two deletions was confirmed by DNA sequencing. Additional peaks potentially corresponding to known and novel additional CNPs were also observed. Our results demonstrate that HR-CGH allows the detection of copy-number changes in any given region of the human genome comprehensively and at an unprecedented level of resolution. Keywords: high resolution comparative genome hybridization (HR-CGH)
Project description:Analysis of DNA from 89 oral lesions by whole genome tiling-path array comparative genomic hybridization. Keywords: array comparative genomic hybridization Genomic DNA isolated from 89 formalin-fixed paraffin-embedded oral dysplasias and tumors, then profiled by whole genome tiling-path array CGH to identify DNA copy alterations for each case.