Basal Core Promoter Double Mutations Research Articles

Quadruple mutation GCAC1809-1812TTCT acts as a biomarker in healthy European HBV carriers.

Many mutation analyses of the HBV genome have been performed in the search for new prognostic markers. However, the Kozak sequence preceding precore was covered only infrequently in these analyses. In this study, the HBV core promoter/precore region was sequenced in serum samples from European inactive HBV carriers. Quadruple mutation GCAC1809-1812TTCT was found with a high prevalence of 42% in the Kozak sequence preceding precore among all HBV genotypes. GCAC1809-1812TTCT was strongly associated with coexistence of basal core promoter (BCP) double mutation A1762T/G1764A and lower HBV DNA levels. In vitro GCAC1809-1812TTCT lead to drastically diminished synthesis of pregenomic RNA (pgRNA), precore mRNA, core, HBsAg, and HBeAg. Calculation of the pgRNA secondary structure suggests a destabilization of the pgRNA structure by A1762T/G1764A that was compensated by GCAC1809-1812TTCT. In 125 patients with HBV-related cirrhosis, GCAC1809-1812TTCT was not detected. While a strong association of GCAC1809-1812TTCT with inactive carrier status was observed, BCP double mutation was strongly correlated with cirrhosis, but this was only observed in absence of GCAC1809-1812TTCT. In conclusion, our data reveal that GCAC1809-1812TTCT is highly prevalent in inactive carriers and acts as a compensatory mutation for BCP double mutation. GCAC1809-1812TTCT seems to be a biomarker of good prognosis in HBV infection.

Locus 5p13.1 may be associated with the selection of cancer-related HBV core promoter mutations.

Background: The basal core promoter (BCP) double mutations (A1762T and G1764A) of hepatitis B virus (HBV) have been reported to be an aetiological factor of hepatocellular carcinoma (HCC). What distinguishes the subset of HBV carriers in whom these mutations are selected?Methods: A genome-wide association study (GWAS) was carried out on 218 asymptomatic HBsAg carriers infected with HBV with BCP double mutations and 191 controls infected with HBV with the wild type BCP. The highest ranking nucleotide polymorphisms (SNPs) were validated with other study subjects, 203 cases and 181 controls. The expression of the gene nearest a SNP found to be significant was examined using RT-PCR.Results: Forty-five candidate SNPs were identified in the GWAS. Three SNPs were found to be associated with the selection of HBV BCP double mutations in the replication stage, including rs7717457 at 5p13.1, rs670011 at 17q21.2, rs2071611 at 6p22.2. Especially, rs7717457 (P= 4.57×10-5 combined P) reached the potential GWAS significance level. The expression of gene complement component 7 (C7), nearest to SNP rs7717457, differed significantly between the case and control groups (t=2.045, P=0.04), suggesting that SNP rs7717457 was associated with the expression of its nearest gene.Conclusions: SNP rs7717457 is associated with the selection of HBV BCP double mutations, providing an important clue to understanding the mechanisms of oncogenesis of HBV BCP double mutations.

Des-γ carboxyprothrombin may not be a good biomarker for hepatocellular carcinoma in those chronically infected with hepatitis B virus with basal core promoter double mutations (T^{1762}, A^{1764}), a prospective study.

The accuracy of des-γ -carboxyprothrombin (DCP) in the detection of hepatocellular carcinoma (HCC) in those infected hepatitis B virus (HBV) from cross-sectional or case-control studies is contradictory. To resolve this contradiction using a prospective study. Three hundred male individuals persistently infected with HBV were recruited from the Chinese cohort and followed up once per year from 2012 to 2015. Each subject was screened for HCC by measurements of serum alpha-fetoprotein (AFP), lectin-bound α -fetoprotein (AFP-L3), DCP concentrations and ultrasonographic examinations. Nineteen HCC cases were identified. The area under receiver operating characteristic (AUROC) at first, second and third visit for AFP, AFP-L3 and DCP ranges from 0.710-0.897, 0.566-0.637 and 0.520-0.595, respectively. The rate of elevated DCP is not significantly different between the HCC cases and controls (52.6% vs. 47.4%) (P > 0.05). The incidence of HCC in subjects with elevated DCP is not significantly higher than that of those with normal DCP (9.5% vs. 4.6%) (P > 0.05). The AUROC of combinations of these biomarkers was higher than that of AFP alone at the first visit. However, it was reduced at the second visit. At the third visit, the AUROCs of AFP + DCP and AFP + AFP-L3 + DCP, but not that of AFP + AFP-L3, were higher than that of AFP alone. AFP but DCP or AFP-L3 remains a valuable biomarker for HCC in those chronically infected with HBV. The combination with AFP-L3 and DCP may not increase the accuracy of AFP in differentiating HCC cases from controls, among those infected with HBV.

Hepatitis B Virus Core Promoter Double Mutations (A1762T, G1764A) Are Associated with Lower Levels of Serum Dihydrolipoyl Dehydrogenase

Objectives: The aim of this study was to identify serum proteins with differential concentrations between hepatocellular carcinoma (HCC) patients and HBsAg asymptomatic carriers among individuals infected with hepatitis B virus (HBV) with basal core promoter (BCP) double mutations (A1762T, G1764A). Methods: iTRAQ and liquid chromatography-tandem mass spectrometry were used to identify differentially expressed protein, and an ELISA test was used for the validation test. Results: The total number of proteins identified was 1,125, of which 239 showed statistically significant differences in their expression. The relative concentrations of serum dihydrolipoyl dehydrogenase (DLD), which showed the most significant correlation with liver diseases and infection, were significantly lower in HCC patients than asymptomatic HBsAg carriers and individuals negative for HBsAg. However, only the difference between HCC patients with BCP double mutations and HBsAg-negative individuals could be confirmed by ELISA. Meanwhile, we found that the concentrations of serum DLD in those infected with HBV with BCP double mutations were significantly lower than in individuals with the wild-type BCP. However, the difference in the concentrations of serum DLD between individuals with wild-type BCP and those negative for HBsAg was not significant. Conclusions: HBV with BCP double mutations are associated with lower concentrations of serum DLD.

The incidence rate over 10 years of naturally occurring, cancer related mutations in the basal core promoter of hepatitis B virus

Cross-sectional analyses showed that the prevalence of basal core promoter (BCP) double mutations (nt 1762T, 1764A) of hepatitis B virus (HBV) gradually increases with age. We aimed to determine the incidence rate of the mutations over 10years. Study subjects were selected from the Long An cohort established in 2004, including 59 with HBV with single mutations at nt 1762 or 1764 in the BCP and 342 with wild type BCP sequences at baseline. Their serum samples for analysis were obtained at the 3rd and 10th annual visits, respectively. The results showed that the annual incidence rate of BCP double mutations is 3.8% (95% confidence interval [CI]: 1.4–6.2) and tends to decrease with age. The peak incidence is in the 30–34years age-group. The incidence rate in HBeAg positive individuals (5.5%) is significantly higher than in those without HBeAg (3.4%) (P<0.05). The incidence rate is significantly higher in genotype C (4.8%) than in genotype B (2.8%) or I (3.1%). The incidence rate of the mutations (6.8%) developing from a single mutation at nt 1762 or 1764 is significantly higher than that (3.8%) from the wild type sequence (P<0.005). The difference in incidence of single mutations between nt 1762 (0.7%) and 1764 (0.03%) is significant (P<0.05). In conclusion, the incidence rate of BCP double mutations tends to decrease with age after the age of 35years. Viruses with a single mutation at nt 1762 or 1764 are more prone to develop double mutations. Nt 1762 is the more common site of the first mutation.

The correlation between serum HBsAg levels and viral loads depends upon wild-type and mutated HBV sequences rather than the HBeAg/anti-HBe status.

Despite several studies regarding the correlation between serum HBsAg titers and viral loads, the association remains uncertain. Eighty‐nine individuals were selected randomly from a Chinese cohort of 2,258 subjects infected persistently with hepatitis B virus (HBV) for cross‐sectional and longitudinal analysis. Viral loads of mutant HBV are lower than those of wild type HBV. The serum HBsAg titers correlate positively with viral loads in both HBeAg positive and negative subjects (r = 0.449, P = 0.013; r = 0.300, P = 0.018, respectively). No correlation between serum HBsAg titer and viral loads was found in any of the four phases of chronic HBV infection. The serum HBsAg titers correlate positively with viral loads in the group with wild type sequences of the PreS/S, basal core promoter (BCP), and preC regions of HBV(r = 0.502, P = 0.040). However, the correlation was not seen in the group with mutations in these regions (r = 0.165, P = 0.257). The correlation between HBsAg titers and viral loads was seen in individuals with wild type PreS/S sequences but not in the subgroup with BCP double mutations or PreC stop mutation, although their sequences in the preS/S regions were wild type. All these findings were confirmed by the longitudinal analysis. In conclusion, the correlation between serum HBsAg levels and viral loads may not differ between HBeAg positive and negative individuals but may depend on wild‐type or mutated genomic sequences. Therefore, HBsAg quantitation may be used as a surrogate for viral loads in only wild‐type HBV infections. J. Med. Virol. 87:1351–1360, 2015. © 2015 The Authors. Journal of Medical Virology Published by Wiley Periodicals, Inc.

Clinical utility of complex mutations in the core promoter and proximal precore regions of the hepatitis B virus genome.

The core promoter and proximal precore regions are the most complex portions of the hepatitis B virus (HBV) genome. These regions cooperatively regulate viral replication and differentially regulate the synthesis of the viral proteins E, core, and X. Multiple mutations in these regions are associated with the persistency of viral infection and the development of cirrhosis and hepatocellular carcinoma (HCC). In South Korea, nearly all HBVs are classified as HBV genotype C2; the majority of these viruses have the basal core promoter double mutation, a precore stop mutation, or both. These mutations may play a role in the alteration of viral and clinical features, and abundant and complex mutations are particularly prevalent in the core promoter and proximal precore regions. We previously demonstrated that the accumulation of ≥ 6 mutations at eight key nucleotides located in these regions (G1613A, C1653T, T1753V, A1762T, G1764A, A1846T, G1896A, and G1899A) is a useful marker to predict the development of HCC regardless of advanced liver disease. In addition, certain mutation combinations were predominant in cases with ≥ 4 mutations. In cases with ≤ 5 mutations, a low Hepatitis B e antigen titer (< 35 signal to noise ratio) was indicative of HCC risk. Viral mutation data of the single HBV genotype C2 suggest that the combined effect of the number and pattern of mutations in the core promoter and proximal precore regions is helpful in predicting HCC risk.

Hepatitis B virus genotypes and genome characteristics in China.

To analyze the hepatitis B virus (HBV) characters in China, as well as the correlation between several HBV mutation and hepatitis symptoms. A total of 1148 HBV genome sequences from patients throughout China were collected via the National Center For Biotechnology Information database (information including: genotype, territory and clinical status). HBV genotypes were classified by a direct reference from the Genbank sequence annotation, phylogenetic tree and online software analysis (http://www.ncbi.nlm.nih.gov/projects/genotyping/formpage.cgi). The phylogenetic tree was constructed based on the neighbor-joining method by MEGA5.0 software. HBV sequences were grouped based on phylogenetic tree and the distance between the groups was calculated by using the computer between group mean distance methods. Seven hundred and twelve HBV sequences with clear annotation of clinical symptoms were selected to analyses the correlation of mutation and clinical symptoms. Characteristics of sequences were analyzed by using DNAStar and BioEdit software packages. The codon usage bias and RNA secondary structures analysis were performed by RNAdraw software. Recombination analysis was performed by using Simplot software. In China, HBV genotype C was the predominant in Northeastern, genotype B was predominant in Central Southern areas, genotype B and C were both dominant in Southwestern areas, and the recombinant genotype C/D was predominant in Northwestern areas. C2 and B2 were identified as the two major sub-genotypes, FJ386674 might be a putative sub-genotype as B10. The basal core promoter double mutation and pre-C mutation showed various significant differences between hepatitis symptoms. In addition to ATG, many other HBV initiation codons also exist. HBV has codon usage bias; the termination codon of X, C and P open reading frames (ORF) were TAA, TAG, and TGA, respectively. The major stop codons of S-ORF were TAA (96.45%) and TGA (83.60%) in B2 and C2 subtype, respectively. This study recapitulated the epidemiology of HBV in China, and the information might be meaningful critical for the future prevention and therapy of HBV infections.

The Effect of HBV Genotype C on the Development of HCC Differs Between Wild-Type Viruses and Those With BCP Double Mutations (T1762A1764)

Background:Association of hepatitis B virus (HBV) genotype C with hepatocellular carcinoma (HCC) development remains controversial. HBV basal core promoter (BCP) double mutations (T1762A1764) are very strong confounding factors of genotypes B and C in HCC development.Objectives:To investigate the association of HBV genotype C with HCC development after controlling for BCP double mutations.Materials and methods:Four hundred and two serum samples from patients with HCC, liver cirrhosis (LC) and chronic hepatitis (CH) and also from asymptomatic HBsAg carriers were analyzed.Results:Genotypes B (31.1%), C (62.8%), and I (6.1%) were detected. With the severity of liver disease the prevalence of genotype B decreased, but genotype C increased. No trend was found for genotype I. The prevalence of BCP double mutations in genotypes C and I viruses was significantly higher than genotype B. BCP double mutations are risk factors for CH, LC and HCC. Genotype C was not identified as a particular risk factor for HCC prior to the stratification analysis but after that genotype C viruses with BCP double mutations were found to be a particular risk factor for HCC (P = 0.008, OR = 17.19 [95% CI: 2.10 - 140.41]), but those with the wild-type BCP were not. In the interaction analysis, genotype C and BCP double mutations were found to have a synergistic effect on HCC development (P < 0.0001, OR = 52.56 [95% CI: 11.49-240.52]).Conclusions:The effect of HBV genotype C on the development of HCC differs between wild-type viruses and those with BCP double mutations, suggesting that not all individuals infected with genotype C HBV are at increased risk of HCC.

Hepatitis B virus mutations related to liver disease progression of Korean patients

Hepatitis B virus (HBV) infection is a global health problem and more than 350 million people worldwide are chronic carriers of the virus. Despite the recent dramatic decline in HBV chronic patients through successful programs of hepatitis B surface antigen vaccination, South Korea is still recognized as an endemic area of HBV infection. HBV infections in South Korea exhibit several distinct features in epidemiologic and clinical aspects. In this review paper, we summarize the distinct HBV mutation patterns related to clinical severity and the molecular epidemiologic traits in Korean chronic patients based on previous reports. Generally, several lines of evidence, including our previous results, have led to the conclusion that a combination of the exclusive predominance of genotype C2, which is prone to mutations, the high prevalence of basal core promoter double mutations, and the presence of distinct immune responses against HBV proteins in the Korean population may generate the distinct HBV variants rarely or not encountered in other areas, which results in distinct clinical manifestations in Korean chronic patients. This may provide a novel insight into the relationships between clinical severity, HBV genotype distribution, and HBV naturally occurring variants.

Shift in the hepatitis B virus genotype distribution in the last decade among the HBV carriers from eastern India: Possible effects on the disease status and hbv epidemiology

In a previous study from eastern India, the prevalence of HBV/C has been increasing among the blood donors. In order to analyze whether there has been any shift in HBV genotype distributions in recent years, the HBV genotypes prevalent during the periods 2000-2002 (Group-I; n=176) and 2007-2009 (Group-II; n=203) were compared, with special attention to changes in the proportion of HBV/C. The rate of prevalence of the three HBV genotypes (A, C, and D; percent prevalence 19.9/21.6/58.5 in Group-I vs. 31.0/28.6/40.4 in Group-II) underwent significant changes with increases in HBV/A and HBV/C among the HBV carriers (0.002). Among the asymptomatic carriers, the prevalence of these two genotypes (P=0.021 for HBV/A and P=0.005 for HBV/C) was significantly high. A notable increase was also observed among the chronic liver disease cases. HBV/A increased significantly among the older age Groups (≥ 51 years), whereas the increase of HBV/C was significant among the younger age Groups (≤ 20 years). With the increase of HBV/A and HBV/C, the rates of basal core promoter double mutation (1762T/1764A) also increased considerably. Binary logistic regression analysis revealed that both HBV/A and 1762T/1764A mutations are predictors of chronic liver disease state over asymptomatic carrier state. Thus, this study highlights the possible influence of HBV genotype shift on the changing scenario of HBV epidemiology and disease in the population.

Combined core promoter mutations and pre‐S deletion of HBV may not increase the risk of HCC: a geographical epidemiological study in Guangxi, China

Although persistent hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC), the mechanisms of oncogenesis remain obscure. To determine whether the findings that HBV basal core promoter (BCP) A1762T, G1764A double mutations, pre-S deletions and a combination of both are risk factors of HCC are supported by geographical epidemiology. Study subjects were recruited from Long An county, where the incidence of HCC is the highest, and five other counties in Guangxi, where the HCC incidence is lower and varies among them. The Pre-S region and BCP of HBV from all study subjects were amplified and sequenced and the data were analysed using chi-squared tests. The prevalence of BCP and pre-S mutations differs significantly (χ(2) = 9.850, 5.135, respectively, all P < 0.01) between Long An and the other counties. However, the prevalence of combined BCP and pre-S mutations does not differ significantly (χ(2) = 1.510, P > 0.05). These mutations are less frequent in the young but the prevalence of pre-S deletions does not increase with age. The prevalence of these mutations does not differ significantly between men and women but is significantly higher in Zhuang than the other ethnic populations. Among the other five counties, the prevalence of BCP mutations in counties where the HCC incidence is high is significantly higher than that of counties where the HCC incidence is low. Combined BCP double mutations and pre-S deletion may not increase the risk of HCC, although these mutations are a risk factor of HCC when they present alone.

Effects of hepatitis B virus mutations on its replication and liver disease severity.

Hepatitis B virus (HBV), nowadays, is one of the major human pathogens worldwide. Approximately, 400 million people worldwide have chronic HBV infection. Only 5% of persons infected during adulthood develop chronic infection. The reverse is true for those infected at birth or in early childhood, i.e. more than 90% of these persons progress to chronic infection. Currently, eight different genotypes o f HBV have been identified, differing in nucleotide sequence by greater than 8%. In addition, numerous subgenotypes have a l s o been recognized based on the nucleotide sequence variability of 4- 8%. It has invariably been found that these genotypes and mutations play a pivotal role in the liver disease aggravation and virus replication. The precore mutations (G1896A) and the double mutation (T1762/A1764) in the basal core promoter are important mutations that alter expression of the hepatitis B e antigen (HBeAg). The HBeAg is important for establishing viral persistence. The precore G1896A mutation abrogates the expression of HBeAg. Numerous other mutations alter the disease severity and progression. It is predictive that the infected patient has high risk of hepatocellular carcinoma if the genotype C is incriminated or if HBV possesses basal core promoter double mutation. Association of the remaining genotypes have been noted but with less degree than genotype C. Phenotypic assays of the different HBV protein markers with different molecular techniques illustrate the replication efficiency of the virus in cell lines. This review will discuss various mutations into their association with liver disease severity and progression as well as virus replication.

Precore Mutation of Hepatitis B Virus May Contribute to Hepatocellular Carcinoma Risk: Evidence from an Updated Meta-Analysis

BackgroundStudies focused on the correlation of mutations in the genome of Hepatitis B Virus (HBV) like Pre-S mutation, Basal Core promoter (BCP), Enhancer II (EnhII), especially Precore mutation, with the risk of hepatocellular carcinoma (HCC) have triggered stiff controversies. With an increasing number of studies in this field recently, we conducted this meta-analysis to appraise the correlations.MethodsWe searched the commonly used databases both in English and Chinese till February 1st, 2012. Meta-analysis was performed in fixed/random-effects models using STATA 10.0. Publication bias was examined through Egger's test and Begg's funnel plot.ResultsIn total, 85 case-control studies were included involving 16745 HBV-infected patients, of whom 5781 had HCC. Statistically significant correlations were observed in Precore mutation G1896A (OR = 1.46, 95% confidence interval [CI] = 1.15–1.85, POR = 0.002), G1899A (OR = 3.13, 95%CI = 2.38–4.13, POR<0.001) and Pre-S mutation especially Pre-S1 deletion (OR = 2.94, 95%CI = 2.22 to 3.89) and Pre-S2 deletion (OR = 3.02, 95%CI = 2.03 to 4.50). Similar correlation existed between BCP double mutation A1762T/G1764A, T1753V, C1653T and HCC. In subgroup analysis, the Asians, genotype C or HBeAg positive patients with certain above mutations may be more susceptible to HCC. Besides, the mutations like G1896A and BCP double mutation may be associated with the progression of the liver diseases.ConclusionsPrecore mutation G1896A, G1899A, deletions in Pre-S region as well as the other commonly seen mutations correlated with the increased risk of HCC, especially in Asians and may predict the progression of the liver disease.

Hepatitis B Virus Double Mutations is There any Role in Pathogenesis of Hepatocellular Carcinoma in Young Patients

Background: The incidence of hepatocellular carcinoma (HCC) below age 40 years old in our institution were relatively high compared with other institutions in Asia. Hepatitis B virus (HBV) basal core promoter (BCP) double mutations correspond with increasing age. The aim of this study was to know if there was any role of HBV double mutations in young HCC patients. Method: A descriptive study was performed on HBV related HCC patients in Cipto Mangunkusumo Hospital in May 2006-November 2008. Patient were recruited consecutively and divided in to two groups, below 40 and above 40 years old. The genotypes were examined by polymerase chain reaction (PCR) method. The alpha feto protein (AFP) values were diagnosed based on ELISA method. The BCP A1762T/G1764A double mutations were examined by direct sequencing. Results: There were 49 HBV related HCC samples consist of 14 (28.5%) samples with age below 40 years old and 35 (71.5%) samples with age above 40 years old. We only found two genotype, genotype B was dominant in patients with HBV related HCC compare to genotype C, 43 (88%) and 6 (12%) respectively. The increasing of AFP level above 400 ng/mL was only found in about half of the samples, 7 (50%) 40 years old. Double mutations of A1762T/G1764A in BCP occurred in 5 (36%) 40 years old. Conclusion: The incidence of HBV related HCC in young patients were relatively high. The proportion of patients with AFP level < 400 ng/mL in patients below 40 years old were higher compared to patients above 40 years. Keywords : hepatocellular carcinoma, BCP double mutation, HBV genotype

The association of HBV core promoter double mutations (A1762T and G1764A) with viral load differs between HBeAg positive and anti-HBe positive individuals: A longitudinal analysis

Background/AimsAlthough there have been a few reports regarding the effect of basal core promoter (BCP) double mutations (A1762T and G1764A) on hepatitis B viral loads, the association remains uncertain. We aim to determine the association after controlling for HBeAg – a strong confounding factor.MethodsWe selected randomly 190 individuals from a Chinese cohort of 2258 subjects for cross-sectional analysis and 56 of the 190 for longitudinal analysis of viral loads.ResultsIn multivariable analysis of the cross-sectional data, BCP double mutations are significantly associated with lower viral loads in HBeAg positive subjects but no difference was found in anti-HBe positive subjects. Triple mutations at nucleotide (nt) 1753, 1762 and 1764 and mutations between nt 1809 and 1817, precore stop mutation (nt 1896) and genotype are not associated with viral loads in either HBeAg or anti-HBe positive subjects. Analysis of the longitudinal data yielded similar results to the cross-sectional data. Viral loads differ significantly between individuals infected with wild-type and BCP double mutations prior to HBeAg seroconversion but this difference is lost after seroconversion.ConclusionsBCP double mutations are associated with lower viral loads in HBeAg positive individuals but have no effect on the viral loads of anti-HBe positive individuals.

Hepatitis B virus pre-S deletion mutations are a risk factor for hepatocellular carcinoma: a matched nested case-control study.

A matched nested case–control study of 33 paired cases and controls was conducted, based on a study cohort in Long An county, Guangxi, China, to determine whether infection with hepatitis B virus (HBV) with pre-S deletions is independently associated with the development of hepatocellular carcinoma (HCC), without the confounding effects of basal core promoter (BCP) double mutations. The prevalence of pre-S deletions was significantly higher in HCC (45.5 %, 15 of 33) than the controls (18.2 %, 6 of 33) (P<0.01), under the control of the influence of BCP double mutations. Most of the pre-S deletions occurred in, or involved, the 5′ half of the pre-S2 region and the difference between HCC (93.3 %, 14 of 15) and controls (66.7 %, four of six) was significant for this region (P=0.015). There was no significant difference in pre-S deletions between the BCP mutant group and BCP wild-type group (P>0.05), nor was the prevalence of pre-S deletions significantly different between genotypes B and C (P>0.1). These results suggest that pre-S deletions constitute an independent risk factor for HCC and their emergence and effect are independent of BCP mutations. The 5′ terminus of pre-S2 is the favoured site for the deletion mutations, especially in HCC cases. Further prospective studies are required to confirm the role of these mutations in the development of HCC.

Comparison of complete sequences of hepatitis B virus genotype C between inactive carriers and hepatocellular carcinoma patients before and after seroconversion

Most patients who acquire chronic hepatitis B virus (HBV) infection by perinatal transmission become inactive carriers (IC) after hepatitis B e (HBe) antigen seroconversion, whereas some patients have persistent abnormal serum transaminase levels and develop hepatocellular carcinoma (HCC) in the anti-HBe-positive phase. The aim of this study was to investigate the HCC-related mutations of HBV. Complete sequences of HBV were examined among eight IC and eight HCC patients infected with HBV genotype C before and after seroconversion. The frequency of the T1653 mutation tended to be higher among HCC patients after seroconversion (16.7% vs. 62.5%; P = 0.086). The prevalence of a basal core promoter double mutation (T1762/A1764) was high among both IC and HCC patients after seroconversion (83.3% vs. 87.5%; P = 0.825). Among the HCC patients, a pre-S deletion mutant was detected in 62.5% patients before seroconversion, and in 37.5% patients after seroconversion. The core deletion mutant was also detected in 50% of HCC patients only before seroconversion. Deletion mutants of the pre-S or core region before seroconversion were significantly associated with HCC patients (0% vs. 62.5%; P = 0.007, 0% vs. 50%; P = 0.021, respectively). Our data showed a significant association of pre-S and core deletion mutants before seroconversion with HCC development. The T1653 mutation after seroconversion was frequently found in HCC patients infected with HBV genotype C. These results suggest that mutations may be predictive factor for development of HCC.

Analysis of hepatitis B virus quasispecies distribution in a Korean chronic patient based on the full genome sequences

Although Korea is a hepatitis B virus (HBV) endemic area, relatively few full-length genome sequences are available. In particular, no comparative analysis has been performed on the full-genome sequences of different HBV quasispecies from a single Korean patient. This report describes the full-length sequences of five HBV clones (two clones with shorter PCR amplicons and three clones with longer amplicons). Large deletions, that is, 685-bp, 487-bp, and 144-bp, that might interfere with the production of normal proteins were observed in four of five clones. Double mutations in the basal core promoter (BCP) region (T1762/A1764) were detected in two clones but no precore mutations (A1896) were detected in any of the five clones. These data support previous results that genotype C, in particular Korean clones of this genotype, is prone to mutations. Two independent mechanisms, namely, the deletions of long lengths and amino acid substitutions followed by BCP double mutations might contribute to the diversity of HBV quasispecies. Considering the importance of HBV quasispecies as HBV variant sources, the distribution of HBV quasispecies in mutation prone genotype C prevalent areas like Korea, should be monitored to improve the management of chronic HBV infections and to control HBV variants that arise due to the administration of vaccine or antiviral therapy.