RNA methylation is one of the hot topics in the study of epigenetics recently and N6-methyladenosine (m6A) modification is the main type of methylation in mammals RNA. The latest studies have found that RNA m6A methylation plays a significant role in the replication of hepatitis B and C viruses and development of related liver cancer. This paper aims to review the research progress on the roles and mechanisms of RNA m6A in the replication of hepatitis viruses and development of hepatocellular carcinoma (HCC), which might provide the theoretical basis and new research insights for the related diseases.

Objective:To examine the correlation between DEPDC5 rs5998152 variants and the risk of hepatitis C virus (HCV) related liver diseases onset. Methods:Patients with chronic hepatic diseases diagnosed as HCV infection in Tianjin Second People′s Hospital from September 2016 to July 2017 were enrolled in the study and were divided into chronic hepatitis C (CHC) group, CHC related liver cirrhosis (LC) group and hepatocellular carcinoma (HCC) group. DEPDC5 rs5998152 was genotyped using the matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) assay and the case data were reviewed. T test, analysis of variance (ANOVA), and non-parametric test were used to perform the comparison of the quantitative data between groups according to normally distributed or not. Chi-square test was used to examine the different distribution of enumeration data between groups. Logistic regression analysis was employed to analyze the correlation between the genetic polymorphism and risk of LC and HCC. Results:A total of 147 patients were included in this study, with 55 in CHC group, 54 in LC group and 48 in HCC group. The levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), α-fetoprotein (AFP), total bilirubin and rate of hepatic encephalopathy were significantly higher in LC and HCC groups compared to CHC group( P<0.05). And the levels of AFP and total bilirubin were significantly higher in HCC group than LC group ( P<0.05). There was no significant difference among the three groups in terms of DEPDC5 rs5998152 genotype distribution ( P > 0.05). The frequency of the C allele at DEPDC5 rs5998152 was higher in LC and HCC subjects than in CHC patients ( P<0.05) and the Logistic analysis indicated that CHC individuals with C allele and TC+ CC genotypes showed higher risk of LC and HCC compared with those with T allele and TT genotype ( P<0.05). In addition, the difference of DEPDC5 rs5998152 allele frequency was not significant between LC and HCC groups and it was not correlated with risk of HCC for LC patients. Conclusions:DEPDC5 rs5998152 may be a risk factor of progression to LC and HCC in the Chinese Han patients with CHC.

Cyclin G1 is a new member of the Cyclin G family, while it is not the main molecule for regulating cell cycle functionally. Cyclin G1 has been found to play important roles in the replication of hepatitis viruses and development of hepatocelluar carcinoma(HCC). This paper aims to review the research progress on the characteristics of Cyclin G1 protein sequence, the interaction of Cyclin G1with microRNA, the roles and mechanisms of Cyclin G1 in the replication of HBV and HCV as well as the development of HCC, which might provide the theoretical basis and new research insights for the related diseases.