ABSTRACT. We investigate the potential association of miR-149C>T and miR-499A>G polymorphisms and the risk of hepatocellular carcinoma (HCC). A matched case-control study of 152 cases and 304 controls were conducted. The miR-149C>T and miR-499A>G genotypes were analyzed using duplex polymerase chain reaction with restricted fragment length polymorphism. HCC patients were more likely to be smokers and drinkers, have hepatitis B and C virus infections, and a family history of cancer. The miR-149 CC genotype was associated with a reduced risk of HCC, while the miR-499 GG genotype was associated with an increased risk of HCC. However, we did not find that the miR-149 CC and miR-499 GG genotypes were associated with risk of HCC, and no interaction was found between miR-149C>T and miR-499A>G polymorphisms and hepatitis B virus infection. In conclusion, the miRNA-149C>T and miR-499A>G polymorphisms were found to play an important role for HCC risk in China. This finding could be useful in identifying people at high risk for the disease for early intervention.

ABSTRACT. Hand, foot, and mouth disease (HFMD) is a systemic illness in children and is usually caused by enterovirus 71 (EV71). To provide new insights into the genetic features of EV71 and the relationship between the overall codon usage pattern of this virus and that of humans, values for relative synonymous codon usage (RSCU), effective number of codons (ENC), codon adaptation index (CAI), and nucleotide composition were calculated and analyzed. The relationship between ENC values and (G+C) 3 % suggests that, although nucleotide composition plays an important role in shaping the overall codon usage pattern of this virus, other factors also affect this pattern. In addition, the negative correlation between the CAI value and (G+C) 3 % suggests that the secondary structure of the EV71 coding sequence caused by its nucleotide composition can affect gene expression. Moreover, there was no significant correlation between ENC and CAI, suggesting that gene expression does not play a role in shaping the overall codon usage pattern of EV71. The overall codon usage pattern of the EV71 virus is only partly similar to the general codon pattern of human, suggesting that, although EV71 has co-evolved with humans for extended periods, mutation pressure played an important role in shaping the virus's overall codon 337 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 13 (1): 336-343 (2014) Enterovirus 71 related to hand, foot and mouth disease usage pattern. These results revealed that the EV71 virus has developed a subtle strategy during evolution for adapting to environmental changes in its host cells solely by means of mutation pressure.