Prevalence of mutations in core promoter/precore region in Japanese patients with chronic hepatitis B virus infection

We examined the frequency and significance of mutations in the core promoter and precore region in 103 Japanese patients with chronic hepatitis B virus (HBV) infection. HBV DNAs from the patients' sera were amplified by polymerase chain reaction and were directly sequenced. A double mutation (T1762 A1764) in the core promoter was frequently observed in the patients regardless of HBeAg status except for asymptomatic carriers with HBeAg. Furthermore, a mutation at nucleotide 1753 from T to C or G was frequently found in anti-HBe positive patients and was often accompanied by the double mutation. The A1896 mutation was found in only about one fourth of the patients with anti-HBe. These data suggest that the patients with chronic liver diseases frequently had a double mutation regardless of HBeAg status and a mutation at nucleotide 1753 might be associated with HBeAg-negative chronic hepatitis B virus infection.     

X gene and precore region mutations in the hepatitis B virus genome in persons positive for antibody to hepatitis B e antigen: comparison between asymptomatic "healthy" carriers and patients with severe chronic active hepatitis

Hepatitis B virus (HBV) carriers with antibody to hepatitis e antigen comprise asymptomatic carriers (ASCs), who have low replication levels of HBV, and patients with chronic active hepatitis (CAH), who have high levels of viral replication. To investigate whether defects in the X protein might be responsible for this difference in the level of viral replication, nucleotide sequences of X and precore gene regions in serum HBV were analyzed in 19 ASCs and 9 CAH patients. All patients had a point mutation creating a stop codon in the precore region. Seventeen ASCs (87.3%) had identical mutations consisting of 4 noncontiguous 1-bp deletions or an 8-bp deletion, both of which truncate the normal X protein, whereas no CAH patient had an X gene mutation (P < .001). Thus, deletion of the X protein might be responsible for the low levels of viral replication in ASCs.     

Association of mutations in the core promoter and precore region of hepatitis virus with fulminant and severe acute hepatitis in Japan

It was recently reported that mutations in the precore and core promoter region of hepatitis B virus (HBV) are associated with fulminant hepatitis. The aim of this study was to investigate the association of mutations in the precore and core promoter region of HBV with fulminant and severe acute hepatitis. We studied Japanese patients with acute HBV infection, including seven patients with fulminant hepatitis, 12 with severe acute hepatitis and 41 with acute self-limited hepatitis. The presence of HBV mutants was examined by using a point mutation assay to detect a G to A transition at position 1896 in the precore region and an A to T transition at position 1762 and a G to A transition at position 1764 in the core promoter region. Significant differences in the proportion of mutations in the precore or core promoter region were present between patients with fulminant hepatitis and self-limited acute hepatitis (7/7 (100%) vs 4/41 (9.8%), P<0.01) and between severe acute hepatitis and self-limited acute hepatitis (6/12 (50.0%) vs 4/41 (9.8%), P<0.01). The frequency of mutation increased proportionately with the severity of disease in patients with acute HBV infection. Fulminant hepatitis B in Japan is closely associated with mutations in the core promoter and precore gene of HBV. Point mutation assays for HBV precore and core promoter analysis may be useful to predict the outcome of liver disease in patients with acute HBV infection.     

Psychological adjustment of children with mild and moderately severe asthma

In chronic hepatitis B virus (HBV) infection seroconversion from hepatitis B e antigen (HBeAg) to hepatitis B e antibody (HBeAb) may be followed either by remission of the disease with low-level viraemia, or by continuing inflammation with high-level viraemia. In both situations the virus may acquire a mutation in the precore sequence which prevents it from encoding HBeAg. We now show that the number of amino acid substitutions in the HBV core is low in viral sequences from patients with HBeAg positive chronic liver disease and HBeAg negative HBeAb positive patients in remission, but the frequency of substitutions is high in HBeAg, negative HBeAb positive patients with active liver disease. Furthermore we show that these substitutions cluster in the promiscuous CD4+ T-helper-cell epitope and in HBV core/e antibody binding determinants, but are not found in regions recognized by major histocompatability complex (MHC) restricted cytotoxic T lymphocytes. Sequential viral sequences from patients before and after HBeAg/HbeAb seroconversion shows that core mutations arise either at the same time or after the precore stop mutation which prevents the virus from encoding HBeAg. These results are consistent with the hypothesis that after clearance of HBeAg, mutations in regions of the virus recognized by CD4+ helper T cells and B cells allow persistence of the HBe negative virus in HBeAb positive patients with viraemia and active hepatitis.     

Hepatitis B virus genomic sequence in the circulation of hepatocellular carcinoma patients: comparative analysis of 40 full-length isolates

We determined full-length nucleotide sequence of hepatitis B virus (HBV) genome in sera from 40 Japanese patients with HBsAg-positive hepatocellular carcinoma (HCC), in order to obtain information on HCC-specific characteristics, if any, of the HBV genome. Direct sequencing of the long distance PCR products starting from 50 microliters of serum samples revealed that 95% of our isolates were of genotype C, and that mutations and deletions/insertions were very common. With respect to envelope protein genes, deletions and missense mutations were frequent in preS2, and the determinant a domain of HBsAg was rich in "antibody-escape" mutations. Within the precore/core region, the most remarkable mutation was the replacement of proline of wild type by other amino acids at codon 130 of the core gene, which was found in 58% of our isolates, while precore-stop mutation was found in 45%. Most interestingly, however, about 90% of our isolates had mutations at nt positions 1762 (A-to-T) and 1764 (G-to-A) within the core promoter, which had been implicated in "e-suppressive" phenotype of HBV genome. G-to-A at nt 1613 and C-to-T at nt 1653 within enhancer II and T-to-C/A at nt 1753 within core promoter were also evident: 38%, 53%, and 40%, respectively. It was interesting that some of the characteristics observed in our isolates form HCC patients had been previously implicated in fulminant hepatitis and/or acute exacerbation of chronic hepatitis.     

Functional analysis of HBV genomes from patients with fulminant hepatitis

Two previous case reports suggest that hepatitis B virus (HBV) core promoter variants with a high replication competence contribute to the pathogenesis of fulminant hepatitis B (FHB). We recently found in HBV genomes from patients with FHB an accumulation of mutations within the core promoter region. Therefore, the aim of this study was to investigate the phenotype of these HBV variants. Replication competence and expression of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) of viral genomes from seven patients with FHB and one patient with fulminant recurrent hepatitis after liver transplantation were analyzed by transfection experiments in human hepatoma cells. Compared with wild-type virus, the HBV variants from the seven patients with FHB produced similar or slightly lower levels of intracellular replicative intermediates and extracellular viral particles. In contrast, the HBV genomes from the patient with fulminant recurrent hepatitis synthesized and secreted significantly more HBV DNA. All genomes tested expressed similar or even higher levels of HBeAg compared with wild-type virus, except for those from four patients with a precore stop codon mutation in the respective dominant viral populations. The level of HBsAg produced by all variant genomes was similar or reduced compared with wild-type virus. These data indicate that in some cases HBV variants with enhanced replication competence and/or a defect in HBeAg expression may contribute to the development of FHB. However, neither phenotype is an essential prerequisite; thus, an additional role of other viral or host factors in the pathogenesis of FHB is suggested.     

Sequential changes in full-length genomes of hepatitis B virus accompanying acute exacerbation of chronic hepatitis B

BACKGROUND/AIM: During the course of persistent hepatitis B virus infection, viral replication markedly decreases after acute exacerbation of liver inflammation accompanied by emergence of antihepatitis B e antibody (anti-HBe) and/or anti-hepatitis B surface antibody (anti-HBs). In some cases, however, persistent viral replication continues even after such exacerbation with or without HBeAg/anti-HBe seroconversion. The aim of the present study was to investigate the extent of genetic variations of HBV in this phenomenon. METHODS: Full-length HBV genomes were amplified by polymerase chain reaction from sera of three patients before and after acute exacerbation and were directly sequenced. RESULTS: In the whole genomes of 3215 nucleotides, only six nucleotide mutations for six amino acid substitutions (2 in the surface gene, 2 in the X gene, 1 in the core gene and 1 in the polymerase gene) were observed in patient 1, 15 mutations for 14 amino acid substitutions (1 in the pre-core codon 28, 4 in the surface gene, 4 in the core gene and 5 in the polymerase gene) were observed in patient 2, and 5 mutations for 6 amino acid substitutions (2 in the surface gene, 2 in the X gene, pre-core stop codon mutation and 1 in the polymerase gene) were observed in patient 3. Substitution in the a determinant of the surface gene, which encodes target epitopes for neutralizing antibodies, as well as those in the pre-core/core gene, which encodes epitopes for cytotoxic T cells, were mainly found. CONCLUSION: HBV that remained after the emergence of anti-HBe and anti-HBs are considered to possess mutations in epitopes for both humoral and cellular immunity. These mutant HBV may be involved in the pathogenesis of persistent hepatic injury after acute exacerbation.     

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Hepatitis B virus (HBV) mutants have recently been identified in patients with acute or fulminant as well as chronic infections. Naturally occurring mutations have been identified in all viral genes and regulatory elements. Mutations in the gene coding for the hepatitis B surface antigen (HBsAg) may result in infection or viral persistence despite the presence of antibodies against HBsAg (anti-HBs) ("vaccine escape" or "immune escape"). Mutations in the gene encoding the pre-core/core protein (pre-core stop codon mutant) result in a loss of hepatitis B e antigen (HBeAg) and sero-conversion to antibodies to HBeAg (anti-HBe) with persistence of HBV replication (HBeAg minus mutant). Mutations in the core gene may lead among others to an immune escape due to a T cell receptor antagonism. Mutations in the polymerase gene can be associated with viral persistence or resistance to nucleoside analogues. Thus, HBV mutations may affect the natural course of infection, viral clearance and response to antiviral therapy. The exact contribution of specific mutations to diagnosis and therapy of HBV infection as well as patient management in clinical practice remain to be established.     

Spontaneous seroconversion in chronic hepatitis B: role of mutations in the precore/core gene

The mechanism underlying spontaneous clearance of hepatitis B e antigen (HBeAg) and the appearance of antibodies (anti-HBe seroconversion) in chronic hepatitis B is not known. Previous studies have demonstrated mutations within the precore/core gene before, during, and after seroconversion, suggesting that the emergence of mutations in the core gene may abrogate tolerance and that this event may act as a general principle for the initiation of the clearance of HBeAg. To investigate this hypothesis, we studied three patients with adult-acquired chronic hepatitis B virus (HBV) infection before spontaneous seroconversion by sequential sequencing and single-stranded conformation polymorphism (SSCP) analysis of the entire precore/core genome. In one patient, a new viral strain appeared six months before seroconversion, but no mutations or new viral strains could be detected in the other two patients. SSCP analysis confirmed the sequencing results and revealed no evidence for the emergence of new viral subpopulations before seroconversion. These results suggest that the appearance of nucleotide changes within the precore/core region of the dominant viral strain is not a prerequisite for the induction of seroconversion in patients with chronic hepatitis B virus infection acquired during adulthood.     

Relativistic density-dependent Hartree-Fock approach for finite nuclei

Two precore predominant mutations of human hepatitis B virus (HBV) at either nucleotide (nt) 1896 or nt 1899 often occur in combination. At nt 1896, a G to A mutation creates a TAG stop codon at codon 28 of precore protein. At nt 1899, a G to A mutation changes glycine at codon 29 to aspartic acid. To assess the effect of each individual mutation as well as any interaction between these two mutations, HBV derivatives bearing one or both precore predominant mutations have been constructed. HBV e-Ag-negative mutants bearing a TAG stop codon mutation at codon 28 uniformly replicate at least 20-fold better than mutants bearing a TGA stop codon at the same amino acid position, irrespective of the sequence context at nt 1899. A single mutation at nt 1899, changing the wild-type G to a pyrimidine (T or C) is deleterious to viral RNA encapsidation and DNA replication. Our results explain in part why only a purine (G or A) at nt 1899, never a pyrimidine, is observed in natural HBV genomes. The effects caused by these two closely linked mutations on viral replication are not independent of each other. The stringent selection for a highly efficient RNA encapsidation element may play a crucial role in the natural occurrence of these two closely linked precore mutations. The putative 27-amino-acid peptide resulting from the truncation of precore by the nt 1896 mutation has no apparent effect on viral replication. The preferential occurrence of the G to A mutation at nt 1896 and 1899, instead of at other nonpredominant positions, is likely to be a combined consequence of both selection and higher intrinsic mutation frequency at these positions.     

Hepatitis B virus with X gene mutation is associated with the majority of serologically "silent" non-b, non-c chronic hepatitis

Hepatitis B virus (HBV) with X gene mutations has been a putative pathogen of chronic hepatitis without serological markers of known hepatitis viruses. The aim of this study was to reconfirm whether the HBV with the X gene mutation is associated with these serologically "silent" non-B, non-C (NBNC) chronic hepatitis, alcoholic liver disease (ALD) and autoimmune hepatitis (AIH). HBV DNA was amplified from serum and sequenced in 30 patients with NBNC chronic hepatitis in comparison with 20 patients with ALD and 5 patients with AIH. HBV DNA was identified in 21 patients (70%) in NBNC chronic hepatitis by nested polymerase chain reaction while only one patient (5%) in ALD and none in AIH showed HBV DNA. Eighteen (85.7%) of the 21 identified HBV DNAs had an identical 8-nucleotide deletion mutation at the distal part of the X region. This mutation affected the core promoter and the enhancer II sequence of HBV DNA and created a translational stop codon which truncated the X protein by 20 amino acids from the C-terminal end. All the HBV DNAs had a precore mutation at the 83rd nucleotide resulting in disruption of HBe antigen synthesis. These results indicate that HBV mutants are closely associated with the majority of serologically "silent" NBNC chronic hepatitis cases and the population of such mutant HBV DNAs is not uniform.     

Point mutations in the S and pre-S2 genes observed in two hepatitis B virus carriers positive for antibody to hepatitis B surface antigen

Two hepatitis B virus (HBV) carriers who had antibodies to HBV surface antigen (anti-HBs) were studied. Case 1 was a 47 year old woman positive for hepatitis B e antigen (HBeAg), and case 2 was a 61 year old man positive for antibody to HBeAg (anti-HBe) and DNA-polymerase (DNA-p). Neither case had received the HBV vaccine. The nucleotide sequences of the HBV-DNA extracted from the patients' sera were determined within the pre-S2 and S genes. Seven out of nine S gene clones from case 1 and six out of nine S gene clones from case 2 had an amino acid replacement from Thr or Ile to Ser at codon 126 in the alpha-determinant of the S gene. Amino acid substitution of codon 145 of the S gene previously reported was not observed. Although two previous reports on HBV escape mutant carriers with both anti-HBs and HBeAg described some deletions in the pre-S2 gene, our cases did not show these deletions. Our analysis indicated that carriers with the HBV escape mutant did not always have pre-S2 gene deletions. We found two HBV escape mutant carriers who had amino acid substitutions at codon 126 in the S gene due to point mutation without any deletions in the pre-S2 gene.     

High degree of conservation in the hepatitis B virus core gene during the immune tolerant phase in perinatally acquired chronic hepatitis B virus infection

BACKGROUND: Mutations in the hepatitis B virus genome have been implicated in the persistence of hepatitis B virus infection and the pathogenesis of hepatitis B virus related liver disease. In view of the heterogeneity in published sequences, data from cross-sectional studies of unrelated subjects cannot differentiate true mutations from infections with variant sequences. AIMS/METHODS: We compared the hepatitis B virus core gene sequences of 42 HBsAg positive subjects from 11 Chinese families with those of the index patients (maternal carriers) to determine the frequency and rate of true hepatitis B virus core gene mutations in patients with chronic hepatitis B virus infection. RESULTS: Completely identical nucleotide sequences were present in all the family members and index patients in two families, suggesting that the hepatitis B virus core gene can be conserved for more than 20 years. The high degree of sequence conservation in these families is related to the young age of the subjects (mean 19.2+/-8.9 years), the fact that they were all HBeAg positive and that 75% of them had persistently normal aminotransferase levels. Longitudinal studies confirmed that mutations were rare in those who remained HBeAg positive with normal aminotransferase levels (immune tolerant phase), but significantly more common in HBeAg positive subjects who had elevated aminotransferase levels and in those who cleared HBeAg (immune clearance phase), the rates of nucleotide and amino acid changes were respectively: 0.28+/-0.12 vs 1.30+/-0.26/10(3) nt position/yr and 0.04+/-0.01 vs 0.18+/-0.5/10(2) codon/yr. CONCLUSIONS: Identical nucleotide differences could be found in the sequences of all the subjects in some families. These differences were more likely to be due to intra-familial transmission of stable variants. Sequence analysis based on comparisons with published sequences would have led to over-reporting of mutations. The hepatitis B virus core gene can remain highly conserved for more than two decades during the immune tolerant phase of perinatally acquired chronic hepatitis B virus infection. However, significant changes can occur within 2-3 years during the immune clearance phase.     

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The clinical importance of hepatitis B virus (HBV) genome variability has been reported recently. One example is the occurrence of hepatitis B virus pre-core mutants, which arise during spontaneous or interferon-induced seroconversion from HBeAg to anti-HBe and are thought to be selected by immune pressure. A survey of HBV pre-core mutants and viral genotypes in 35 HBeAg negative patients during interferon therapy was carried out to understand viral pathogenesis in this form of chronic hepatitis B. Seventeen patients responded to interferon therapy as assessed by the sustained normalization of serum ALT levels and the significant decrease of viremia levels. The response rate to interferon was independent of both initial serum viral DNA level and interferon doses. During interferon therapy, a significant decrease of M0 (wild-type pre-core sequence at pos. 1887-1908), M1 (TGG to TAG at pos. 1896) or M2 (TGG to TAG at pos. 1896, and GGC to GAC at pos. 1899) positive viral genomes was found in 48%, 42%, and 33% of patients, respectively. A higher response rate to interferon therapy was observed in patients infected with HBV genotype A (70%) or M0 positive strains (75%) as compared to patients infected with genotype D/E (40%) or M1/M2 positive strains (44%). The data support the hypothesis that pre-core defective HBV represent viral mutants with an increased capacity to resist exogenous alpha interferon. These findings emphasize that characterization of HBV genome variability prior to interferon therapy may help to predict antiviral response in HBeAg negative patients.     

The sequential occurrence of viral mutations in a liver transplant recipient re-infected with hepatitis B: hepatitis B immune globulin escape, famciclovir non-response, followed by lamivudine resistance resulting in graft loss

BACKGROUND/AIMS: The purpose of this study was to characterize the clinical, histological and virological events in an orthotopic liver transplant (OLT) recipient with recurrent hepatitis B infection who was initially managed with hepatitis B immune globulin (HBIg) and when viral recurrence occurred, with nucleoside analogue salvage therapy. The aims were to document the mutations occurring in the hepatitis B virus (HBV) polymerase gene as a consequence of HBIg escape, famciclovir non-response and subsequent lamivudine resistance. METHODS: Throughout the follow-up of 796 days, the patient was seen at least at 4-week intervals. Clinical, biochemical and virological data were registered according to protocol. HBV DNA was quantified throughout the treatment period. The viral polymerase gene was sequenced from serum samples collected at representative time intervals. Consecutive liver biopsies were scored according to the modified Knodell classification. RESULTS: Clinically, the patient was in excellent condition until the development of acute hepatitis during the lamivudine therapy period, 765 days post-OLT. Until this terminal event, serum transaminase activity was only 1-2 times the upper limit of normal with serum bilirubin and prothrombin time within the normal range. Subsequent liver biopsies showed chronic active hepatitis with no signs of fibrosis. The post-mortem biopsy showed severe acute hepatitis B with massive necrosis. The HBV polymerase gene was sequenced during HBIg, famciclovir and lamivudine treatment. One mutation I533L was detected during HBIg treatment. No amino acid changes were selected during famciclovir treatment. Three amino acid changes were selected while the patient was on lamivudine treatment, which include L533I, S559T and M550I. CONCLUSIONS: We have documented HBV recurrence in a liver transplant recipient with the emergence of a multidrug resistant HBV which caused graft loss. The primary resistance to famciclovir in spite of therapeutic penciclovir levels may be as a result of a combination of the mutations found in the polymerase region. After 300 days of lamivudine treatment, a drug-resistant population emerged which was associated with a greater than three log increase in HBV DNA and contributed to loss of graft function. This is the first report of such an adverse clinical outcome due to the emergence of a mutant virus as a consequence of immunoprophylactic and antiviral therapy in a liver transplant recipient.     

Analysis of hepatitis B virus populations in an interferon-alpha-treated patient reveals predominant mutations in the C-gene and changing e-antigenicity

It is largely unknown whether hepatitis B virus (HBV) sequence variation during chronic infection hampers HBV immune recognition or the antiviral effect of cytokines on HBV production. Here we have analyzed which region of the HBV genome changes most drastically during an interferon-alpha (IFNalpha)-stimulated immune response. In addition, we have investigated whether the mutations affect viral replication, gene expression, and immune recognition of the mutant viral proteins. The study was performed with full-length HBV genomes taken longitudinally from a patient who transiently cleared HBV and seroconverted to anti-HBe during a long-term IFNalpha treatment. We found a replacement of the predominant virus population during IFNalpha therapy The virus populations differed mainly by a cluster of nucleotide changes in the C-gene and a pre-S2 deletion. Most of the newly emerging mutations localized within core/HBe B-cell epitopes, changed HBe antigenicity toward mono- and polyclonal antibodies, and also influenced the reactivity of the anti-HBc/e antibodies of the patient. All genomes tested expressed less HBeAg than wild-type HBV, while replication and IFNalpha susceptibility were similar. These data indicate that IFNalpha therapy can lead to the emergence of HBV variants with mutations mainly affecting recognition of the core/HBe proteins by antibodies. Taken together, the type of core/HBe-specific B-cell immune response, the sequence of the corresponding epitopes, and the HBe expression level appear to contribute to the decision on viral clearance or persistence.     

Molecular mechanism of hepatocarcinogenesis

To clarify the relative role of hepatitis C virus (HCV) and hepatitis B virus (HBV) in hepatocarcinogenesis in hepatitis B surface antigen (HBsAg)-negative hepatocellular carcinoma (HCC) in Taiwan, polymerase chain reaction (PCR) was used to detect the HCV-RNA and HBV-DNA sequences in the serum and liver tissues from 31 HBsAg-negative HCC patients. Twenty-one were positive for antibody to HCV (group 1) and 10 were negative (group 2). Hepatitis C virus-RNA was detected by PCR in the serum of 16 group 1 patients and in the liver tissue of 17; while HBV-DNA was found in the liver tissue of only four, and no HBV-DNA was found in the serum. Hepatitis C virus RNA was detected in the serum of one group 2 patient and in the liver tissue of another. In contrast, HBV viral DNA was found in the serum of four group 2 patients and in the liver tissues of five patients. This indicates that HCV plays an important role in hepatocarcinogenesis in HBsAg-negative patients in Taiwan, especially in those with antibody to HCV. In those without antibody to HCV, HBV might still be associated with the development of HCC in a significant proportion of such patients. In order to study the role of the p53 mutation in hepatocarcinogenesis, we investigated the status of the p53 mutation in 61 HCC samples from Taiwan. The exon 5 to 8 of the p53 gene in the tumour tissue of 61 HCC were amplified and sequenced. A total of 20 cases (32.8%) were found to have mutations: 36.6% (15/41) from the HBsAg-positive group and 25.0% (5/20) from the HBsAg-negative group. The corresponding normal liver showed no mutation. The mutation is widely distributed throughout the exon 5 to 8. Only four cases (6.6%), all positive for HBsAg, had a specific hotspot mutation at codon 249 with G to T transversion. These results show that scattered point mutations in p53 are not uncommon in HCC samples from Taiwan and may be important in the development of this cancer. However, the aflatoxin-related specific mutation seems much less related to the genesis of HCC in Taiwan. To study the role of telomerase activity in hepatocarcinogenesis, a total of 39 HCC tissues and the corresponding non-tumour liver tissues were analysed. The results showed that telomerase activity was detected in all the 39 tumour tissues, while it could be detected in six of the 39 non-tumour liver tissues. The high positive rate of telomerase activity in HCC samples suggests that telomerase activity is closely related to the development or progression of HCC. To determine whether exon 1 and exon 2 of the p16 gene are altered in HCC, thirty-four tumours from 30 HCC patients were examined by DNA sequencing analysis of PCR-amplified genomic DNA. Homozygous deletions of MTS1/p16/CDKN2 exon 1 were identified in 1/34 primary tumours (3%), no mutations or rearrangements were found in these specimens. These data suggest that alterations of MTS1/p16/CDKN2 gene are rarely found in HCC, and might play little role in the development of this cancer. To study the clonality of HCC, 18 patients with multiple HCC, most of them small in size, were analysed by DNA fingerprinting. In patients positive for hepatitis B surface antigen, the integration pattern of hepatitis B viral DNA in liver tissue was also analysed. The results by both methods showed that 8/9 hepatitis B surface antigen-positive patients were different in clonality. In the remaining nine patients negative for hepatitis B surface antigen, four had different band patterns in their tumours by DNA fingerprinting. This study indicated that polyclonality of multiple HCC was rather frequent and it highlighted the importance of eliminating the underlying cause of liver injury to improve the survival of these patients. Microsatellite markers were used to study the genetic changes of HCC. Thirty cases of HCC, most of them small in size, were studied. A total of 242 microsatellite markers mapping to 1-22 and X chromosomes was used. The results showed that the range of loss of het