The reversed evolution from multicellularity to unicellularity during carcinogenesis
ABSTRACT: Using xenograft-based experimental evolution, we characterize the full life history from initiation to metastasis of a tumor at the genomic and transcriptomic levels. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from cell lines or xenograft tumor samples.
Project description:A cell line (MFD-1) was derived from a 55-year old male with oesophageal adenocarcinoma. Using different sources of genetic material from normal and tumour tissue surgically resected, peripheral blood and the derived cell line a high concordance of genotypes calls across the whole genome confirms MFD-1 was derived from parent tumour. The SNP6 array contained 906,000 probes for the genotyping of SNPs and 946,000 probes for the genotyping of non-polymorphic copy number. Affymetrix CEL files were analysed using the tool PICNIC2 (predicting absolute allele copy number variation with microarray cancer data).
Project description:One lung tumor and its adjacent normal were profiled for copy-number alterations with the high-resolution Affymetrix SNP6.0 Array. The SRA ID for the high throughput sequencing project will accompany our study is SRP002045. One lung tumor sample and an adjacent normal sample were assayed on the Affymetrix SNP6.0 array.
Project description:Constitutional epimutations of tumor suppressor genes manifest as promoter methylation and transcriptional silencing of a single allele in normal somatic tissues, thereby predisposing to cancer. Constitutional MLH1 epimutations occur in individuals with young-onset cancer and demonstrate non-Mendelian inheritance through their reversal in the germline. We report a cancer-affected family showing dominant transmission of soma-wide highly mosaic MLH1 methylation and transcriptional repression linked to a particular genetic haplotype. The epimutation was erased in spermatozoa but reinstated in the somatic cells of the next generation. The affected haplotype harbored two single nucleotide substitutions in tandem: c.-27C>A located near the transcription initiation site and c.85G>T. The c.-27C>A variant significantly reduced transcriptional activity in reporter assays and is the probable cause of this epimutation. Five members of a three-generation Caucasian Lynch syndrome family with an autosomal dominant MLH1 epimutation linked to a single nucleotide variant (c.-27C>A) within the MLH1 5'UTR were examined for copy number variations and retention of heterozygosity on chromosome 3. These five carriers of constitutional MLH1 methylation and the c.-27C>A variant were compared with 300 healthy Caucasian controls from the Wellcome Trust Case Control Consortium using three algorithms (QuantiSNP, PennCNV, COKGEN) to detect any copy number variants. The five family members studied were female (the proband II5, her affected mother I1, and three asymptomatic relatives II2, II4 and III2) are labeled according to the pedigree in Figure 3 of the associated publication (Hitchins et al., Cancer Cell, 2011). The supplementary file 'GSE30348_gw6.lrr_baf.txt' contains log R ratio and B-allele frequency values in a tab-delimited format with one marker per row.
Project description:Single cell derived clones were extracted from four glioblastoma tumors using fluorescence activated cell sorting with CD15 and CD133 markers. Unsorted bulk tumors were also derived. Genotyping and copy number analysis was carried out for each tumor separately. Patient blood was used as control for three tumors while the fourth tumor had no blood available and a control cohort of 226 individuals was used for the latter (see Silversides, C.K., et al., Rare copy number variations in adults with tetralogy of Fallot implicate novel risk gene pathways. PLoS genetics, 2012. 8(8): p. e1002843.)
Project description:Lynch syndrome, caused by germline heterozygous mutations of the DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2, or deletions affecting the EPCAM gene upstream of MSH2, is characterized by a predisposition to early-onset colorectal and additional extracolonic cancers. An alternative but rare cause of Lynch syndrome is a constitutional epimutation of MLH1, which is characterized by promoter methylation and transcriptional silencing of a single allele in normal tissues. Worldwide, five families with autosomal dominant transmission of a constitutional MLH1 epimutation linked to an MLH1 haplotype with two single nucleotide variants (c.-27C>A and c.85G>T) have been identified. Array-based genotyping using Affymetrix SNP 6.0 data in four of these families revealed a shared haplotype extending across a ≤2.6 Mb region of chromosome 3p22 encompassing MLH1 and additional flanking genes, indicating common ancestry. Genomic DNA from 5 carriers of the c.-27C>A and c.85G>T variants was hybridized on Affymetrix SNP6.0 array according to manufacturer's procedures
Project description:Metastatic uveal melanoma (MUM) is chemoresistant and usually fatal within one year of diagnosis. There is an urgent need to better understand disease pathogenesis, in order to determine key drivers of the metastatic process that could be effectively targeted by therapy. Gene copy number variations occurring in a rare cohort of 13 metastatic and six matched primary, formalin-fixed, paraffin-embedded uveal melanoma samples were identified using the Affymetrix Genome-Wide Human SNP 6.0 Array. Gross chromosomal abnormalities commonly seen in primary UM and associated with the development of metastasis were observed in the MUMs. The most common CNVs were gene amplifications on chromosome 8q, especially in the region 8q24.3. Interestingly, deletions on chromosome 3 were detected at a lower frequency. Genomic profiles of PUM-MUM pairs varied in their degree of similarity and complexity. No genes were altered being unique to either all PUMs or all MUMs of the pairs, but 135 gene CNVs were consistently shared. Of these genes, 125 were amplifications located on chr. 8q24.3. Five genes in the region 8q24.3 and two genes on chromosome 3 were selected for validation by immunohistochemistry because of their known function in cancer (BCL6, C-MYC, E2F5, PTP4A3, SNAI2, and WISP1), or known importance in UM pathology (BAP1). The functional effect of these CNVs on protein expression was confirmed; amplified genes showed increased expression and deleted genes reduced expression. To conclude, our data demonstrate frequent amplification of chromosome 8q in MUMs, suggesting that genes facilitating the expansion of UM in the metastatic niche occur in this region. Furthermore, validation of a range of amplified 8q genes at the protein level strongly indicates the CNVs may be functional and, contribute to MUM biology. 19 samples in total: 13 metastatic uveal melanoma (MUMs) and in six cases their paired primary UM (PUMs)
Project description:Analysis of DNA from fixed tissues specimens of 58 primary uveal melanomas, with known clinical outcome, to determine gene copy number variations that were associated with survival. Abstract: Uveal melanomas can be stratified into subgroups with high or low risk of metastatic death, according to the presence of gross chromosomal abnormalities. Where a monosomy 3 uveal melanoma is detected, patient survival at three years is reduced to 50%. However, approximately 5% of patients with a disomy 3 tumour ultimately develop metastasis, and a further 5% of monosomy 3 uveal melanoma patients’ exhibit disease-free survival for more than five years. Despite extensive knowledge of the chromosomal abnormalities occurring in uveal melanoma, the genes driving metastasis are not well defined. Gene copy number variations occurring in a well-characterised cohort of 58 formalin-fixed, paraffin-embedded uveal melanoma samples were identified using the Affymetrix SNP 6.0 whole genome microarray. Four genetic sub-groups of primary uveal melanoma were represented in the patient cohort: 1) disomy 3 with long-term survival; 2) metastasizing disomy 3; 3) metastasizing monosomy 3; and 4) monosomy 3 with long-term survival. Cox regression and Kaplan-Meier survival analysis identified three genes that were associated with differences in patient survival. Patients with an amplification of CNKSR3 (6q) or RIPK1 (6p) demonstrated longer survival than those with gene deletions or no copy number change (log rank, p=0.022 and p<0.001, respectively). Conversely, those patients with an amplification of PENK (8q) showed reduced survival (log rank p<0.001). CNKSR3, RIPK1 and PENK are novel candidate metastasis regulatory genes in uveal melanoma. This is the first report of amplification of a specific gene on 6p that is associated with improved uveal melanoma patient survival and suggests that the development of uveal melanomas with a propensity to metastasise may be limited by genes on 6p. 58 samples in total. Ten disomy 3 with long-term survival. Fifteen disomy 3 with metastasising. Seventeen monosomy 3 with long-term survival. Sixteen monosomy 3 metastasising.
Project description:Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous disease whose underlying etiology has not been explained by traditional prognostic factors such as tumor site, stage, or histology. Although previous studies have shown that molecular subtypes of HNSCC exist, the benefit of such a classification scheme has not been fully realized. We show that molecular subtypes of HNSCC exist; that these subtypes have distinct patterns of chromosomal gain and loss, some of which affect canonical oncogenes and tumor suppressors; and that the subtypes are biologically and clinically relevant. These subtypes provide new insight into HNSCC etiology, as well as a valuable method for classifying HNSCC tumors. A total of 141 samples were considered. CEL files were subject to quality control (QC) procedures using the Affymetrix Genotyping Console, and arrays that produced contrast QC measurements above the default threshold of .4 were removed from subsequent analysis. The remaining 99 CEL files were processed with aroma, and log2 intensity ratios were produced using a pooled collection of normal samples as a reference. After segmenting the log2 ratios with DNAcopy, the resulting copy number profiles were subjected to manual review. Arrays that produced low quality copy number profiles were removed from subsequent analysis. Copy number values from chr1 - chr22 were considered.
Project description:This study integrated Affymetrix SNPchip data for CNV estimation, Affymetrix HuEx1.0 data for gene expression estimation, and Illumina HumanMethylation27k BeadChip data for promoter methylation to estimate pathway activity. Case:Control with HNSCC tumors and uvulopalatopharyngoplasty (UPPP) samples