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Metadata

Name
Differential Gene Expression between African American and European American Colorectal Cancer Patients
Repository
Gene Expression Omnibus
Identifier
geo.series:GSE28000
Description
The incidence and mortality of colorectal cancer (CRC) is higher in African Americans (AAs) than in other ethnic groups in the U. S., but reasons for the disparities are unknown. We performed gene expression profiling and microsatellite instability (MSI) analysis of sporadic CRCs from AAs vs. European Americans (EAs) to assess the contribution to CRC disparities. We evaluated gene expression of 43 AA and 43 EA CRC tumors matched by stage and 40 normal colon tissues using the Agilent human whole genome 4x44K cDNA arrays. Gene and pathway analysis were performed using Significance Analysis of Microarrays (SAM), 10-fold Cross Validation (10-fCV) and Ingenuity Pathway Analysis (IPA). MSI analysis was assessed with five NIH Bethesda markers. SAM revealed that 95 genes were differentially expressed between AA and EA patients at a false discovery rate of <5%. A 10f-CV demonstrated that 9 genes were differentially expressed between AA and EA with an accuracy of 97%. Nine genes (CRYBB2, PSPH, ADAL, VSIG10L, C17orf81, ARSE, ANKRD36B, ZNF835, ARHGAP6) were validated and differential expression confirmed by qRT-PCR in independent test set of 21 patients (10 AA, 11 EA). We also analyzed MSI in 57 of the CRC subjects. Overall, 15.8% of CRC patients had MSI, with a higher rate observed in EA (20%) than in AA (12%). MSI distribution by tumor site was 77% right and 23% left colon. Previously, genetic, epigenetic and environmental factors have been implicated in the etiology of CRC. Our results are the first to implicate differential gene expression in CRC disparities and support the existence of distinct tumor microenvironments in these two patients' populations.
Data or Study Types
Expression profiling by array
Source Organization
National Center for Biotechnology Information
Access Conditions
available
Year
2012
Access Hyperlink
http://www.ncbi.nlm.nih.gov/sites/GDSbrowser?acc=GSE28000

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