MiR expression profiles of paired primary colorectal cancerand metastases by next-generation sequencing
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ABSTRACT: MicroRNAs (miRs) have been recognized as promising biomarkers. It is unknown to what extent tumor-derived miRs are
differentially expressed between primary colorectal cancers (pCRCs) and metastatic lesions, and to what extent the expression
profiles of tumor tissue differ from the surrounding normal tissue. Next-generation sequencing (NGS) of 220 fresh-frozen samples,
including paired primary and metastatic tumor tissue and non-tumorous tissue from 38 patients, revealed expression of 2245
known unique mature miRs and 515 novel candidate miRs. Unsupervised clustering of miR expression profiles of pCRC tissue with
paired metastases did not separate the two entities, whereas unsupervised clustering of miR expression profiles of pCRC with
normal colorectal mucosa demonstrated complete separation of the tumor samples from their paired normal mucosa. Two
hundred and twenty-two miRs differentiated both pCRC and metastases from normal tissue samples (false discovery rate (FDR)
o0.05). The highest expressed tumor-specific miRs were miR-21 and miR-92a, both previously described to be involved in CRC with
potential as circulating biomarker for early detection. Only eight miRs, 0.5% of the analysed miR transcriptome, were differentially
expressed between pCRC and the corresponding metastases (FDR o0.1), consisting of five known miRs (miR-320b, miR-320d,
miR-3117, miR-1246 and miR-663b) and three novel candidate miRs (chr 1-2552-5p, chr 8-20656-5p and chr 10-25333-3p). These
results indicate that previously unrecognized candidate miRs expressed in advanced CRC were identified using NGS. In addition,
miR expression profiles of pCRC and metastatic lesions are highly comparable and may be of similar predictive value for prognosis
or response to treatment in patients with advanced CRC
PROVIDER: EGAS00001001127 | EGA |
REPOSITORIES: EGA
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