Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Comparative genomic hybridization of human colorectal carcinoma samples - chromosome copy number and LOH analysis

ABSTRACT: Structural changes of chromosomes play important roles in the carcinogenesis of colorectal carcinoma (CRC). Here, by using SNP-typing arrays, we have tried to screen for recurrent chromosome copy number changes and loss-of-heterozygosity in the genome of colorectal carcinoma. Genomic DNA was isolated from tumor and paired normal tissues of CRC (n=94), and was hybridized to Affymetrix Mapping 50K Xba 240 arrays. Chromosome copy number and LOH likelihood score was inferred at every SNP locus with CNAG2.0 software (http://www.genome.umin.jp). Experiment Overall Design: Tumor samples and paired normal tissues (n=94 for each) were hybridized to the microarrays. Signal intensity data as well as genotype data were compared between a pair of tumor and normal samples with CNAG2.0. The resultant copy number and LOH likelihood score for each sample are thus calculated from two datasets (tumor and normal).

ORGANISM(S): Homo sapiens

SUBMITTER: Hiroyuki Mano

PROVIDER: E-GEOD-11417 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Chromosome copy number analysis in screening for prognosis-related genomic regions in colorectal carcinoma.

Kurashina Kentaro K Yamashita Yoshihiro Y Ueno Toshihide T Koinuma Koji K Ohashi Jun J Horie Hisanaga H Miyakura Yasuyuki Y Hamada Toru T Haruta Hidenori H Hatanaka Hisashi H Soda Manabu M Choi Young Lim YL Takada Shuji S Yasuda Yoshikazu Y Nagai Hideo H Mano Hiroyuki H

Cancer science 20080628 9

Colorectal carcinoma (CRC) remains the major cause of cancer death in humans. Although chromosomal structural anomaly is presumed to play an important role in the carcinogenesis of CRC, chromosomal copy number alterations (CNA) and loss of heterozygosity (LOH) have not yet been analyzed extensively at high resolution in CRC. Here we aim to identify recurrent CNA and LOH in human CRC with the use of single nucleotide polymorphism-typing microarrays, and to reveal their relevance to clinical outco ...[more]

PMID: 18564138

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Project description:In colorectal cancer (CRC), chromosomal instability (CIN) is typically studied using comparative-genomic hybridization (CGH) arrays. We studied paired (tumor and surrounding healthy) fresh-frozen tissue from 86 CRC patients using Illumina’s Infinium-based SNP array. This method allowed us to study CIN in CRC, with simultaneous analysis of copy number (CN) and B-allele frequency (BAF), which is a representation of allelic composition. This data helped us to detect mono-allelic and bi-allelic amplifications/deletion, copy neutral loss of heterozygosity, and levels of mosaicism for mixed cell populations, some of which can not be assessed with other methods that do not measure BAF. We identified associations between CN abnormalities and different CRC phenotypes (MSI, histological diagnosis, location, tumor grade, stage, MSI and presence of lymph node metastasis). We showed commonalities between regions of CN change observed in CRC and the regions reported in previous studies of other solid cancers (e.g., amplifications of 20q, 13q, 8q, 5p and deletions of 18q, 17p and 8p). From the Therapeutic Target Database we found relevant drugs, targeted to the genes located in these regions with CN changes, approved or in trials for other cancers and common diseases. These drugs may be considered for future therapeutic trials in CRC, based on personalized cytogenetic diagnosis. We also found many regions harboring genes which are not currently targeted by any relevant drugs that may be considered for future drug discovery studies. Our study shows the application of high-density SNP arrays for cytogenetic study in CRC and its importance for personalized treatment. DNA was extracted from colon tissue samples provided by 86 CRC patients. Each patient provided paired CRC tumor tissue and adjacent normal colon mucosa samples, which were fresh-frozen after resection. Samples were genotyped using Illumina's Infinium-based 610 Quad and CytoSNP 12 microarray chips. The genotype data from paired tumor and normal samples was used to detect tumor-specific chromosomal instabilities in copy number, including copy-neutral LOH, which cannot be assessed by many other cytogenetic methods. Supplementary file "GSE34678_raw_GPL8887.txt" includes the raw data for Samples using GPL8887 (GSM853162-GSM853239); supplementary file "GSE34678_raw_GPL13829.txt" includes the raw data for Samples using GPL13829 (GSM853240-GSM853363).

Project description:Abstract: Altered expression of microRNAs (miRNAs) is associated with development and progression of various human cancers by regulating the translation of oncogenes and tumor suppressor genes. In colorectal cancer (CRC), these regulators complement the Vogelstein multi-step model of pathogenesis and have the potential of becoming a novel class of tumor biomarkers and therapeutic targets. Using QRT-PCR, we measured the expression of 621 mature miRNAs in 40 CRCs and their paired normal tissues and identified 23 significantly deregulated miRNAs. We subsequently evaluated their association with clinical characteristics of the samples and presence of alterations in the molecular markers of CRC progression. Expression levels of miR-31 were correlated with CA19-9 and miR-18a, miR-21 and miR-31 were associated with mutations in APC gene. To investigate the downstream regulation of the differentially expressed miRNAs identified we integrated putative mRNA target predictions with the results of a meta-analysis of seven public gene expression datasets of normal and tumor samples of CRC patients. Many of the CRC deregulated miRNAs computationally map to targets involved in pathways related to progression. Here one promising candidate pair (miR-1 and MET) was studied and functionally validated. We show that miR-1 can have a tumor suppressor function in CRC by directly down-regulating MET oncogene both at RNA and protein level and that re-expression of miR-1 leads to MET driven reduction of cell proliferation and motility, identifying the miR-1 down-modulation as one of the events that could enhance CRC progression. Note: Each sample has the following information: Type - tissue type (T : Tumor or N: Normal), Patient - patient identifier, Stage - tumor stage (I - IV), Status - disease status at last check-up (ED: evident disease, NED: non-evident disease), CEA - carcinoembryonic antigen (continuous), CA199 - carbohydrate antigen 19-9 (continuous), APC - mutation status of APC gene (0: wild-type, 1: mutated), KRAS - mutation status of KRAS gene (0: wild-type, 1: mutated), chr18qLOH - LOH status of 18q (0: no LOH, 1: LOH), TP53 - mutation status of TP53 gene (0: wild-type, 1: mutated). Tumor and normal counter-parts of 40 colorectal cancer patients (10 of each Stage I to IV) where profiled using TaqMan(r) Array Human MicroRNA A+B Cards v2.0

Dataset Information

Comparative genomic hybridization of human colorectal carcinoma samples - chromosome copy number and LOH analysis

Publications

Chromosome copy number analysis in screening for prognosis-related genomic regions in colorectal carcinoma.

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