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Series GSE30540 Query DataSets for GSE30540
Status Public on Jul 04, 2012
Title A new classification of chromosome instability (CIN) phenotype, CIN-high and CIN-low
Organism Homo sapiens
Experiment type Expression profiling by array
Summary Samples were taken from colorectal cancers in surgically resected specimens in 35 colorectal cancer patients. The expression profiles were determined using Affymetrix Human Genome U133 Plus 2.0 arrays. Comparison between the sample groups allow to identify a set of discriminating genes that can be used for molecular markers for CIN phynotype.
Overall design Specimens from 35 consecutive stage II and stage III patients who had undergone surgical resection of CRC were studied. Patients with familial adenomatous polyposis and HNPCC were excluded from the study. Specimens from tumors and corresponding normal tissues in surgically resected specimens were snap-frozen in liquid nitrogen and stored at -80 ºC until use. Parallel tumor specimens were formalin fixed and paraffin embedded for histological examination. DNA and RNA was extracted from paired tumor and normal tissue using frozen samples. The patients provided written, informed consent to the collection of specimens, and the local Ethics Committee approved the study protocol. MSI and LOH phenotype analysis were done as follows;
Using DNA, we performed the polymerase chain reaction (PCR) and determined the MSI status. In addition to five microsatellite markers recommended by the National Cancer Institute workshop, we also used TP53, D18S46, D18S363 and D18S474.9 We determined LOH status in non–MSI-high tumors, because LOH is rare in MSI-high tumors and also interpretation of LOH is difficult in MSI-high tumors. We defined LOH at each locus as a 50% reduction in the height of one of two allele peaks in tumor DNA relative to non-neoplastic control DNA. LOH was defined as present if any of the markers on the same chromosome show LOH. In order to evaluate the severity of chromosomal instability based on the actual frequency of LOH among evaluable loci, we defined the LOH Ratio (%) as:
LOH Ratio (%) = Total number of chromosomes with LOH / Total number of chromosomes that could be evaluated for LOH × 100. Depending on the LOH Ratio, we classified tumors as having high levels of chromosomal instability (CIN-high) (33% < LOH Ratio < 100%) or low levels of chromosomal instability (CIN-low) (0% < LOH Ratio <33%). Furthermore, CIN-high tumors were divided into two subgroups; CIN-high (mild type) (33% < LOH Ratio < 75%) and CIN-high (severe type) (75% < LOH Ratio <100%).
Contributor(s) Watanabe T, Kobunai T, Hashimoto E
Citation(s) 22547595
Submission date Jul 10, 2011
Last update date Mar 25, 2019
Contact name Toshiaki Watanabe
Phone 81-3-5800-8653
Organization name University of Tokyo
Department Department of Surgical Oncology
Street address 7-3-1, Hongo
City Bunkyo-ku
State/province Tokyo
ZIP/Postal code 113-8655
Country Japan
Platforms (1)
GPL570 [HG-U133_Plus_2] Affymetrix Human Genome U133 Plus 2.0 Array
Samples (35)
GSM757713 Expression data of 358_SCa
GSM757714 Expression data of 31_RCa
GSM757715 Expression data of 123_SCa
BioProject PRJNA144487

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Supplementary file Size Download File type/resource
GSE30540_RAW.tar 179.2 Mb (http)(custom) TAR (of CEL)
Raw data provided as supplementary file
Processed data included within Sample table

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