Homo sapiens
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ABSTRACT:
PROVIDER: PRJNA143541 | ENA |
REPOSITORIES: ENA
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Project description:Background. Colorectal cancer develops through two main genetic instability pathways characterized by distinct pathologic features and clinical outcome. Results. We investigated colon cancer samples (23 characterized by microsatellite stability, MSS, and 16 by high microsatellite instability, MSI-H) for genome-wide expression of microRNA (miRNA) and mRNA. Based on combined miRNA and mRNA gene expression, a molecular signature consisting of twenty seven differentially expressed genes, inclusive of 8 miRNAs, could correctly distinguish MSI-H versus MSS colon cancer samples. Among the differentially expressed miRNAs, various members of the oncogenic miR-17-92 family were significantly up-regulated in MSS cancers. The majority of protein coding genes were also up-regulated in MSS cancers. Their functional classification revealed that they were most frequently associated with cell cycle, DNA replication, recombination, repair, gastrointestinal disease and immune response. Conclusions. This is the first report that indicates the existence of differences in miRNA expression between MSS versus MSI-H colorectal cancers. In addition, the work suggests that the combination of mRNA/miRNA expression signatures may represent a general approach for improving bio-molecular classification of human cancer.
2007-09-07 | E-TABM-326 | biostudies-arrayexpress
Project description:Microsatellite instability (MSI), caused by defective mismatch repair, is observed in a subset of colorectal cancers (CRCs). We evaluated somatic mutations in microsatellite repeats of genes chosen based on reduced expression in MSI CRC and existence of a coding mononucleotide repeat. Expression profiling of 34 MSI colorectal cancers and 15 normal colonic mucosas was performed in 2002. Comparison of malignant and healthy tissue.
2011-03-01 | E-GEOD-24514 | biostudies-arrayexpress
Project description:Microsatellite instability (MSI), caused by defective mismatch repair, is observed in a subset of colorectal cancers (CRCs). We evaluated somatic mutations in microsatellite repeats of genes chosen based on reduced expression in MSI CRC and existence of a coding mononucleotide repeat.
2011-03-01 | GSE24514 | GEO
Project description:The CpG island methylator phenotype (CIMP) in colorectal tumors can be recognized by an increased frequency of aberrant methylation in a specific set of genomic loci. Because of the strong association of CIMP with high microsatellite instability (MSI-H), the identification of CIMP+ tumors within microsatellite stable (MSS) colorectal cancers may not be straightforward. To overcome this potential limitation, we have built an improved 7-loci set of methylation markers that includes CACNA1G, IGF2, RUNX3, HTR6, RIZ1, MINT31 and MAP1B. This new set of CIMP markers revealed a bimodal distribution of methylation frequencies in a group of 95 MSS colorectal cancers, which allowed a clearer separation between CIMP classes. Correlation of CIMP+ tumors with bio-pathological traits revealed significant associations with location to the proximal colon, mucinous histology and chromosomal stability. Although not statistically significant, a trend toward an adverse prognosis for CIMP+ cases was observed. Microarray analysis revealed that CIMP+ tumors are characterized by a unique expression profile, a result that confirms that CIMP+ tumors represent a distinct molecular class within MSS colorectal cancers. Moreover, our results suggest that this expression pattern may represent the molecular background for the development of CIMP+ tumors that, in turn, develop MSI when aberrant methylation occurs at the MLH1 gene promoter.
2008-01-01 | E-TABM-328 | biostudies-arrayexpress
Project description:Gene expression signature of colorectal cancer with microsatellite instability.
| PRJNA94475 | ENA
Project description:A large proportion of indigenous African (IA) colorectal cancer (CRC) patients in South Africa are young (<50years), with no unique histopathological or molecular characteristics. Anatomical site as well as microsatellite instability (MSI) status have shown to be associated with different clinicopathological and molecular features. This study aimed to ascertain key histopathological and miRNA expression patterns in microsatellite stable (MSS) and low-frequency MSI (MSI-L) patients, to provide insight into the mechanism of the disease. This study revealed distinct histopathological features for Left Colon Cancer (LCC), and suggests BAT25/26, miRNAs let-7a-5p and miRNA-125a/b-5p as negative prognostic markers in African CRC patients.
2023-12-31 | GSE197088 | GEO
Project description:Details of the series are available in the publication Cardoso J. et al., âChromosomal instability in MYH- and APC-mutant adenomatous polypsâ, Cancer Research, accepted for publication. Abstract of the publication: âThe vast majority of colorectal cancers display genetic instability, either in the chromosomal (CIN) or microsatellite (MIN) forms. While CIN tumors are per definition aneuploid, MIN colorectal cancers, caused by loss of mismatch repair function, are usually near-diploid. Recently, bi-allelic germline mutations in the MYH gene, were found to be responsible for MAP (MYH associated polyposis), an autosomal recessive predisposition to multiple colorectal polyps, often indistinguishable from the dominant FAP (familial adenomatous polyposis) syndrome caused by inherited APC mutations. Here, we analyzed MYH- and APC-mutant polyps by combining laser-capture microdissection, isothermal genomic DNA amplification, and array-CGH (comparative genomic hybridization). Smoothed quantile regression methods were applied to the MAP and FAP genomic profiles to discriminate chromosomes predominantly affected by gains and losses. Up to 80% of the MAP polyps showed aneuploid changes, which is significantly higher than the 60% found among FAP polyps. Both MAP and FAP adenomas were characterized by frequent losses at chromosome 1p, 17, 19 and 22, and gains affecting chromosome 7 and 13. The observation that aneuploidy is already detectable at early stages of MYH-driven tumorigenesis raises the possibility that CIN may contribute significantly to accelerated tumor progression, increased cancer risk, and poor prognosis in MAP.â Details of the series are available in the publication Cardoso J. et al., âChromosomal instability in MYH- and APC-mutant adenomatous polypsâ, Cancer Research, accepted for publication.
2010-06-30 | E-GEOD-3898 | biostudies-arrayexpress
Project description:Immunopeptidomic analyses of colorectal cancers with and without microsatellite instability
| PRJNA802838 | ENA
Project description:Expression profiling of colorectal cancer (CRC) tissue samples with microsatellite instability (MSI)
| PRJNA317494 | ENA