GSE63119
Multiplex-NGS for identification of differentially expressed miRNAs between colon cancer patients with and without metachronous metastases
Purpose: The goal of this experiment was to identify differentially expressed miRNAs between colon cancer patients with and without metachronous metastases. Background: Colon cancer prognosis and treatment are currently based on a classification system still showing large heterogeneity in clinical outcome, especially in TNM-stages II-III. Prognostic biomarkers for metastasis risk are warranted, as development of distant recurrent disease mainly accounts for the high lethality rates of colon cancer. MicroRNAs have been proposed as potential biomarkers for cancer. Furthermore, a verified standard for normalization of the amount of input material in PCR-based relative quantification of miRNA expression is lacking. Methods: A selection of frozen tumor specimens from two independent patient cohorts with TNM-stage II-III microsatellite stable primary adenocarcinomas were used for laser capture microdissection. Next-generation sequencing was performed on small RNAs isolated from colorectal tumors from the Dutch cohort (N=50). Differential expression analysis, comparing in metastasized- and non-metastasized tumors, identified prognostic microRNAs. Validation was performed on colon tumors from the German cohort (N=43) using qPCR. Results: MiR-25-3p and miR-339-5p were identified and validated as independent prognostic markers and used to construct a multivariate nomogram for metastasis risk prediction. The nomogram showed good probability prediction in validation. Additionally, we recommend combination of miR-16-5p and miR-26a-5p as standard for normalization in qPCR of colon cancer tissue-derived microRNA expression. Conclusions: In this international study, we identified and validated an miRNA classifier in primary cancers, and propose a nomogram capable of predicting metastasis risk in microsatellite stable TNM-stage II-III colon cancer. Overall design: Small RNAs of 50 primary colon adenocarcinomas, with and without metachronous metastases, were sequenced using the Illunina HiSeq 2000.