|
|
A common variant in the precursor miR-146a sequence does not predispose to cholangiocarcinoma in a large European cohort |
Florentina Mihalache, Aksana Höblinger, Monica Acalovschi, Tilman Sauerbruch, Frank Lammert and Vincent Zimmer |
Homburg, Germany
Author Affiliations: Department of Medicine II, Saarland University Hospital, 66421 Homburg, Germany (Mihalache F, Lammert F and Zimmer V); Department of Medicine III, University Iuliu Hatieganu, Cluj-Napoca, Romania (Mihalache F and Acalovschi M); Department of Internal Medicine I, University Hospital Bonn, Bonn, Germany (Höblinger A and Sauerbruch T)
Corresponding Author: Vincent Zimmer, MD, Department of Medicine II, Saarland University Hospital, Homburg 66421, Germany (Tel: +49-6841-1623221; Fax: +49-6841-1623264; Email: vincent.zimmer@uks.eu) |
|
|
Abstract BACKGROUND: Micro-RNAs (miRNAs) are small, non-coding RNA species considered to fine-tune basic cellular functions by modulating target gene translation and/or mRNA stability. A common G/C polymorphism (rs2910164) in the precursor (pre-) miR-146a gene engaged in NF-κB signaling and apoptosis pathways has been reported to modulate the genetic risk of hepatocellular carcinoma by increased G-allelic production of mature miR-146a. We investigated rs2910164 in a large European-based cholangiocarcinoma (CCA) cohort.
METHODS: We recruited 182 CCA patients and 350 controls in three academic medical centers. Genotyping for rs2910164 was performed by PCR-based assays with 5-nuclease and fluorescence detection. Genotype frequencies were tested for consistency with the Hardy-Weinberg equilibrium using an exact test; allelic and genotypic differences between the patients and controls were assessed by the Chi-square test and Armitage s trend test. Exploratory subgroup analyses included gender, tumor localization (extra- versus intrahepatic CCA) and early-onset CCA.
RESULTS: Genotype distributions were consistent with the Hardy-Weinberg equilibrium. No significant differences in either allele or genotype distributions were detected between the CCA and control groups or the respective subgroups investigated. However, there was a trend for a protective effect of the heterozygous single-nucleotide polymorphism state GC, as indicated by an underrepresentation in the CCA group in general (29% vs 35%; P=0.18) and, in particular, for extrahepatic tumor sites (26% vs 35%; OR=0.67; 95% CI, 0.43-1.02; P=0.065).
CONCLUSIONS: Our data do not support a prominent contribution of the pre-miR-146a sequence variant in the genetic predisposition to CCA. However, current studies functionally characterizing rs2910164 have proposed that distinct repertoires of target genes are addressed by genotype-specific mature miR-146a species. Given the detected trend towards a potentially protective role of GC heterozygosity, a subtle modulation of genetic CCA risk by the pre-miR-146a GC genotype may exist and should be evaluated further.
|
|
|
|
|
|
|
|