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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Academic Medical Centers, Aged, Bile Duct Neoplasms, Bile Ducts, Intrahepatic, Case-Control Studies, Chi-Square Distribution, Cholangiocarcinoma, Cohort Studies, Female, Gene Frequency, Genetic Predisposition to Disease, Germany, Heterozygote, Humans, Logistic Models, Male, MicroRNAs, Middle Aged, Multivariate Analysis, Odds Ratio, Phenotype, Polymerase Chain Reaction, Polymorphism, Single Nucleotide, RNA Precursors, Risk Assessment, Risk Factors, Romania.
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Does a common variant in the precursor miR-146a sequence predispose to cholangiocarcinoma in a large European cohort? Context: 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. 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. 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).
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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. Final Decision: no