| Background and Objective:During the development of human hepatocellular carcinoma (HCC) many genes are dyregulated; however, the machnism has not been fully elucidated yet. Genes regulation is affected by various factors, such as single nucleotide polymorphism (SNP), copy number variation (CNV), methylation, microRNA (miRNA), etc. MiRNAs play important role in gene regulation through combination with complementary sequence with target mRNA. SNPs located at 3'untranslated regions (UTR) of genes might modulate the expression of genes by affecting their binding ability to certain miRNAs, therefore, be associated with individual susceptibility to cancer development or prognosis. Serum miRNAs, which have been detected in several types of cancer, are potential biomarkers with high sensitivity and stability for tumor diagnosis and prognosis. This study sought to identify genetic variations within 3'UTR of genes that have been shown to be dyregulated in hepatocellular carcinoma to evaluate their effects on susceptibility to HCC and miRNAs in serum as potential biomarkers for HCC diagnosis.Methods:NextBio search engine (www.nextbio.com) was used to find genes dyregulated in RNA level in hepatocellular carcinoma. Patrocles (www.patrocles.org) was used to identify putative SNPs within miRNA target sites. The associations between the identified SNPs and susceptibility to hepatocellular carcinoma were examined in a case-control set consisted of 1,876 patients with hepatocellular carcinoma and 2,044 controls derived from a Han Chinese population. Genotypes were determined by polymerase chain reaction-based restriction fragment length polymorphism and TaqMan platform. Odds ratios (ORs) and their 95% confidence intervals (95% CIs) were computed with unconditional logistic regression model. Candidate serum miRNAs were selected from miRNAs expression profiles reported previously. Serum miRNAs (miR-21, miR-122 and miR-223) were quantified by real-time quantitative RT-PCR in 101 patients with HCC and 89 healthy controls. In addition,48 patients with chronic type B hepatitis were also analyzed for comparison. Real-time RT-PCR was used for quantification of serum miRNAs and Mann-Whitney U test was applied for statistics of levels of serum miRN As.Results:We identified four SNPs, rs4577 (ALDOB 3'UTR C>T), rs10900031(CXCL12 3'UTR G>A), rs17033(ADH1B 3'UTR T>C), rs655445(THRSP 3'UTR G>A), which were suggested to be miRNA binding sites in silico. Case-control analysis showed that the rs4577 TT genotype was associated with significantly increased risk for hepatocellular carcinoma, with the OR being 1.15 (95% CI=1.04-1.27, P=0.020) compared with the CC genotype. Stratified analysis showed that in females the risk is higher with OR being 1.43 (95% CI=1.04-1.27, P=0.008), while no significant association was observed in males. Stratified analysis also showed that significant association was defined in younger subjects below 60 years old. The other three SNPs, rs10900031, rs17033, rs655445, were not associated with suceptibility to hepatocellular carcinoma. Patrocles (www.patrocles.org) suggested that the ALDOB transcript may be a target of hsa-miR-877 and rs4577T allele might have enhanced binding of miRN A-mRNA which may decrease stability and quantity of ALDOB transcript.We found that the median levels of miR-21, miR-122 and miR-223 were significantly higher in patients with HCC than those in healthy controls (P=7.48×10-13, P=6.93×10-9 and P=3.90×10-12, respectively). However, these elevated serum miRNAs were also detected in patients with chronic hepatitis (P=2.05×10-12, P=4.52×10-16, and P=1.65×10-11, respectively). Moreover, serum miR-21 and miR-122 in patients with chronic hepatitis were higher than in patients with HCC (P=3.99×10-4 and P=4.97×10-8), although no such significant difference was found for miR-223. Receiver-operator characteristic curve analyses suggested that these serum miRNAs may be useful markers for discriminating patients with HCC or chronic hepatitis from healthy controls, but not patients with HCC from patients with chronic hepatitis.Conclusions:These results suggest that ALDOB rs4577TT genotype is associated with increased risk of hepatocellular carcinoma, which might be mediated by altered regulation of ALDOB expression in the posttranscription level by hsa-miR-877. Serum miR-21, miR-122 and miR-223 are elevated in patients with HCC or chronic hepatitis and these miRNAs have strong potential to serve as novelbiomarkers for liver injurybut not specifically for HCC.
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