Aflatoxin and p53 abnormality in duck hepatocellular carcinoma

Recent studies have revealed that a point mutation at codon 249 in the p53 gene predominates in hepatocellular carcinoma (HCC) cases from Southern Africa and China, where infection with hepatitis B virus (HBV) and contamination of aflatoxin B₁ in food are risk factors for HCC. This unique mutation from G to T at the third base in codon 249 observed in human HCC cases is suggested to be linked to aflatoxin exposure. Six ducks with HCC, five of which were fed a diet containing aflatoxin B₁ for 1–2 years, were analysed for the presence of point mutations at this codon of the p53 gene by polymerase chain reaction and direct nucleotide sequencing. None of the six ducks with HCC showed the change at this codon regardless of duck hepatitis B virus infection. This suggests that aflatoxin B₁ itself might not be involved in the unique mutation at codon 249 in hepatocar-cinogenesis, or that other factors coincident with aflatoxin may be responsible for this unique mutation.     

HBV转基因小鼠暴露ATB-1后肝脏ATB-1-DNA加成物水平的测定

目的探讨ＨＢＶ与ＡＴＢ１协同致肝癌的机理．方法用ＲＩＡ法测定ＨＢＶ转基因小鼠与正常小鼠暴露ＡＴＢ１后０，０５，１，２，４，８，２４ｈ７个不同时相肝脏ＡＴＢ１ＤＮＡ加成物的含量变化．结果暴露ＡＴＢ１后，ＨＢＶ转基因小鼠肝脏ＡＴＢ１ＤＮＡ加成物含量在各时相均高于正常小鼠，尤以１ｈ高峰时相值（５５９２ｐｍｏｌ／ｍｇ±４１５ｐｍｏｌ／ｍｇ比４１３６ｐｍｏｌ／ｍｇ±２８２ｐｍｏｌ／ｍｇＤＮＡ，Ｐ＜００１）及２４ｈ时相值（２４８７±２０３比９８９±８５，Ｐ＜００１）最显著．２４ｈ后，转基因小鼠肝脏ＡＴＢ１ＤＮＡ加成物仍维持高水平，但正常小鼠已基本恢复至暴露前水平．结论ＨＢＶ转基因小鼠暴露ＡＴＢ１后肝脏ＡＴＢ１ＤＮＡ加成物含量增加可能为ＨＢＶ与ＡＴＢ１协同致肝癌的直接原因．     

Hepatitis B x antigen and p53 in the development of hepatocellular carcinoma

Hepatitis B virus (HBV) is one of the major etiological agents responsible for the appearance of chronic liver diseases, including hepatocellular carcinoma (HCC). There is increasing evidence that the HBV excoded × antigen (HBxAg) is involved in one or more steps that contribute to multistep hepatocarcinogenesis. Recent work has now defined one of these steps as the physical binding and functional inactivation of the tumor suppressor protein, p53, by HBxAg. The centrality of p53 to genomic stability, cell cycle arrest, induction of apoptosis, and in senescence related pathways, suggests that its disruption by HBxAg will result in genomic instability, loss of cell cycle control, a lower apoptotic rate, and an extension in the life span of HBV-infected cells. It is proposed that HBxAg/p53 complex formation represents one of several steps whereby HBV contributes to the development of HCC.     

Hepatitis B virus markers and antibodies to hepatitis C virus in Japanese patients with hepatocellular carcinoma

Sera from Japanese patients with chronic liver disease were tested for hepatitis B virus (HBV) markers and antibodies to hepatitis C virus (anti-HCV), and the results were correlated to the presence of hepatocellular carcinoma. In chronic non-A, non-B liver disease, anti-HCV prevalence was high both in patients with hepatocellular carcinoma (78/89, 88%) and without it (66/84, 79%), while previous HBV infection was more common in patients with hepatocellular carcinoma (65/89, 73%) than in those without it (46/84, 55%) (P<0.05). Coexistence of anti-HCV and antibodies to HBV was observed frequently in patients with hepatocellular carcinoma (56/89, 63%) compared with patients without it (39/84, 46%) (P<0.05). In chronic HBV carriers, anti-HCV was more common in patients with hepatocellular carcinoma (12/38, 32%) than in those without it (3/62, 5%) (P<0.01). These results suggest that infection with the two viruses may be a risk factor for more serious liver disease.This work was supported by a Grant-in-Aid from the Ministry of Education, Science and Culture, Japan.     

Aetiological differences in demographical,clinical and pathological characteristics of hepatocellular carcinoma in The Gambia

Background: Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide, with a high burden in West Africa. Data evaluating aetiological differences in HCC presentation from this region are limited. Aims: The aim of this study was to describe the demographical, clinical and pathological characteristics of HCC by aetiology (hepatitis B or C infection, aflatoxin associated). Methods: One hundred and ninty‐three cases of HCC diagnosed between 1997 and 2001 in The Gambia were analysed. Characteristics were compared by aetiology using χ²‐tests, student t‐test and Wilcoxon's rank sum tests as appropriate. Results: The prevalence of hepatitis B surface antigen, hepatitis C antibody and aflatoxin‐associated 249^serTP53 mutations among HCC patients was 60, 20 and 38% respectively. The typical HCC patient was a 49‐year‐old male positive for hepatitis B surface antigen presenting with hepatomegaly (93%), abdominal pain (94%) and weight loss (95%) 8 weeks after symptom onset. Most patients had multifocal lesions with background cirrhosis. The median largest tumour was 10.3 cm and the median α‐fetoprotein level was 500 ng/ml. Eighty‐four per cent of patients had advanced HCC (patients not meeting the Milan criteria) at presentation. Conclusions: Irrespective of aetiological agent, HCC among West Africans presents at very advanced stages. Few clinical or pathological differences exist by aetiology. More studies are needed to understand the mechanisms of hepatocarcinogenesis among these patients as well as identify high‐risk populations in which early detection through screening will be beneficial.     

Risk factors analysis for hepatocellular carcinoma in patients with and without cirrhosis: a case-control study of 213 hepatocellular carcinoma patients from India

AIM: To assess the role of hepatitis B virus (HBV), hepatitis C virus (HCV) and alcohol intake as risk factors for hepatocellular carcinoma (HCC) in the presence or absence of cirrhosis in Indian population. METHODS: A total of 213 patients with HCC and 254 control subjects not affected with hepatic diseases or neoplasm were recruited. Odds ratios (ORs) were estimated for each risk factor and synergism among various risk factors was also studied. RESULTS: The ORs and 95% confidence intervals (CI) of HCC were 48.02 (25.06-91.98) for any HBV marker, 38.98 (19.55-77.71) for HBsAg positivity, 12.34 (2.84-53.61) for HBsAg negative and antibody positive (either of anti-HBe or total anti-HBc), 5.45 (2.02-14.71) for anti-HCV positive and HCV RNA positive, and 2.83 (1.51-5.28) for heavy alcohol use. No significant risk increase was evident for subjects who were anti-HCV positive and HCV RNA negative. Synergism between alcohol and HCV infection in causing HCC was found, but not between alcohol and HBV. Overall, conclusive evidence of the presence or absence of cirrhosis was reached in 189 (88.73%) HCC patients; cirrhosis was present in 137 (72.48%) of them. ORs with 95% CI of HCC in the presence and absence of cirrhosis, respectively, for HBV were as follows: (i) 48.90 (24.61-97.19) and 35.03 (15.59-78.66) for any HBV marker; (ii) 39.88 (19.41-81.97) and 24.40 (10.60-56.18) for HBsAg positivity; and (iii) 12.10 (2.67-54.88) and 19.60 (3.94-97.39) for HBsAg negativity and antibody positivity. Significantly increased risk was found among cirrhotic patients for anti-HCV positivity and HCV RNA positivity [OR = 7.53 (2.73-20.78)] and for heavy alcohol use [OR = 3.32 (1.70-6.47)]; however, in the absence of cirrhosis, no significant risk increase was evident for subjects who were anti-HCV positive and HCV RNA positive [OR = 0.97 (0.11-8.54)], or who had history of heavy alcohol use [OR = 1.58 (0.55-4.53)]. CONCLUSIONS: Infection with HBV and HCV are the major risk factors for the development of HCC in Indian patients. Presence of HBV antibodies even in the absence of HBsAg conferred increased risk for HCC in the presence or absence of cirrhosis. Anti-HCV positivity in the absence of HCV RNA conferred no increased risk. HCV RNA positivity and heavy alcohol use significantly increased the risk of HCC among cirrhotic patients, but not non-cirrhotic patients.     

Putative association of transforming growth factor‐α polymorphisms with clearance of hepatitis B virus and occurrence of hepatocellular carcinoma in patients with chronic hepatitis B virus infection

Summary. Previous studies showed that several genetic polymorphisms might influence the clinical outcome of chronic hepatitis B virus (HBV) infection, including HBV clearance or development of hepatocellular carcinoma (HCC). The aim of this study was to determine whether polymorphisms of the transforming growth factor‐α (TGF‐α) gene are associated with clinical outcome of HBV infection. A total of 1096 Korean subjects having either present or past evidence of HBV infection were prospectively enrolled between January 2001 and August 2003. Among 16 genetic variants in TGFA gene, nine variants were genotyped using TaqMan assay and the genetic association with HBV clearance and HCC occurrence was analysed. Statistical analyses revealed that TGFA+103461T>C, TGFA+106151C>G and TGFA‐ht2 were marginally associated with clearance of HBV infection. However, only TGFA‐ht2 retained significance after multiple correction (OR = 0.39, P^corr = 0.007 in recessive model). Although no variants were significant after multiple correction, TGFA+88344G>A and TGFA+103461T>C were weakly associated in recessive model in the analysis of HCC occurrence. In addition, Cox relative hazards model also revealed that TGFA+88344G>A was associated with onset age of HCC occurrence in subjects (RH = 1.46, P^corr = 0.04). TGF‐α polymorphisms might be an important factor in immunity, progression of inflammatory process and carcinogenesis, which explains the variable outcome of HBV infection at least in part. Further biological evidence is warranted in the future to support these suggestive associations.     

Combined pre‐S deletion and core promoter mutations related to hepatocellular carcinoma: A nested case‐control study in China

Aim: To investigate the roles of biomedical factors, hepatitis B virus (HBV) DNA levels, genotypes, and specific viral mutation patterns on the progression of hepatocellular carcinoma (HCC) in Qidong, China. Methods: A total of 2387 males (aged 20–65 years) who were seropositive for the hepatitis B surface antigen (HBsAg), but had not been diagnosed with HCC, were recruited to a community‐based HCC screening study from August, 1996. Evaluation of virological parameters at recruitment was determined for 196 HCC patients during 10 years of follow‐up and 323 controls. Results: After adjustment for age at recruitment, history of cigarette smoking and alcohol consumption, alanine aminotransferase (ALT) elevation, alpha‐fetoprotein (AFP) levels >20 ng/mL, hepatitis B e antigen positive, HBV DNA levels ≥4.00 log₁₀ copies/mL, pre‐S deletion, T1653 mutation, T1762/A1764 double mutations, and T1766 and/or A1768 mutations were associated with subsequent risk of HCC. A significant biological gradient of HCC risk by HBV DNA levels from less than 2.69 log₁₀ copies/mL to 6.00 log₁₀ copies/mL or greater was observed. HBV with a complex mutation combination pattern (pre‐S deletion, T1762/A1764 double mutations, and T1766 and/or A1768 mutations) rather than a single mutation was associated with the development of HCC. The longitudinal observation demonstrated a gradual combination of pre‐S deletion, T1762/A1764 double mutations, and T1766 and/or A1768 mutations during the development of HCC. Conclusions: AFP levels >20 ng/mL, high HBV DNA levels, pre‐S deletion, and T1762/A1764 double mutations at recruitment were independent risk factors of HCC. Combination of pre‐S deletion and core promoter mutations increased the risk of HCC.     

An integrated analysis of SOCS1 down‐regulation in HBV infection‐related hepatocellular carcinoma

Persistent inflammation together with genetic/epigenetic aberrations is strongly associated with chronic Hepatitis B virus (HBV) infection‐related hepatocarcinogenesis. Here, we investigated the alterations of the suppressor of cytokine signalling (SOCS) family genes in HBV‐related hepatocellular carcinoma (HCC). A total of 116 patients with HCC were enrolled in this study. The methylation statuses of SOCS1‐7 and CISH genes were quantitatively measured and clinicopathological significance of SOCS1 methylation was statistically analysed. The gene copy number variation was assayed by aCGH. Luciferase reporter assay and Western blot were used to detect the involvement of SOCS1 in p53 signalling. We found high frequencies of SOCS1 gene hypermethylation in both tumour (56.03%) and adjacent nontumour tissues (54.31%), but tumour tissues exhibited increased methylation intensity (24.01% vs 13.11%, P < 0.0001), particularly in patients with larger tumour size or cirrhosis background (P < 0.0001). In addition, the frequency and intensity of SOCS1 hypermethylation in tumour tissues were both significantly higher than those in nontumour tissues in male gender patients and in patients ≥45 years old (P = 0.0214 and P < 0.0001, P = 0.0232 and P < 0.0001, respectively). SOCS1 gene deletion was found in 8 of 25 aCGH assayed tumour specimens, which was associated with lower SOCS1 mRNA expression (P = 0.0448). Furthermore, ectopic SOCS1 overexpression could activate the p53 signalling pathway in HCC cell lines. Hypermethylation of SOCS2‐7 and CISH genes was seldom found in HCC. Our results suggested that the gene loss and epigenetic silencing of SOCS1 were strongly associated with HBV‐related HCC.     

HBsAg-negative hepatitis B virus infections in hepatitis C virus-associated hepatocellular carcinoma

This study was conducted to evaluate reports that hepatitis B virus (HBV) DNA sequences can be found in the serum and/or tumour tissue from some hepatocellular carcinoma (HCC) patients who have no detectable hepatitis B surface antigen (HBsAg) in their sera. Such HBV infections would be highly atypical, because prospective studies have shown a clear succession of specific serologic markers during and after most HBV infections. As most HBsAg-negative HCC patients in Japan have hepatitis C virus (HCV) infections, the present study was conducted to determine whether some of these patients actually have unrecognized HBV infections. Thirty newly diagnosed HCC patients from Kurume, Japan, with antibody to the hepatitis C virus (anti-HCV) were studied. None of the 30 had HBsAg detectable in their serum. Of 22 for whom test results for antibodies to the hepatitis B core antigen (anti-HBc) and antibodies to HBsAg (anti-HBs) were available, 14 (64%) had anti-HBc and anti-HBs, four (18%) had anti-HBc alone, and four (18%) had no HBV markers. Nested polymerase chain reaction was used to detect the HBV surface (S), core (C), polymerase (P) and core promoter gene sequences in the HCC tissues and in the adjacent nontumorous liver tissues. HBV DNA was detected in HCC and/or adjacent nontumorous liver in 22 of 30 (73%) patients [detected in both HCC and nontumorous liver in 19/30 patients (63%)]. Among the 22 patients with detectable HBV DNA, more than one HBV gene was detected in 10 (46%). Among the four patients whose sera were negative for all HBV markers, three had HBV DNA in either HCC and nontumorous liver (two cases) or only in the nontumorous liver (one case); HBV DNA could not be detected in tissues from the fourth patient. In 18 of 21 (86%) patients with detectable HBV core promoter sequences, mutations at both nucleotides 1762 (A-GT) and 1764 (G-A) in the core promoter region were found. No deletions were detected in the core promoter gene region of the type reported to be associated with some cases of HBsAg-negative HBV infection. Thus, HBV DNA was detectable in 22 (73%) HBsAg-negative, anti-HCV-positive HCCs, including three (10%) who were also negative for anti-HBc and anti-HBs. HBV mutations at both nucleotides 1762 (A-GT) and 1764 (G-A) in the core promoter region were found in the majority of cases, mutations that have previously been reported in HBV that is integrated in HCC DNA. In serologic surveys to determine etiologic associations of HCC, patients such as those in this study would have been incorrectly designated as having 'HCV-associated HCC,' whereas the data in this study suggest that HBV could have played a role in the development of their HCCs.     

Lower serum viral loads in young patients with hepatitis-B-virus-related hepatocellular carcinoma

Advanced age and high hepatitis B virus (HBV) DNA level are risk factors associated with the development of HBV-related hepatocellular carcinoma (HCC). However, little is known about the role of viral load in the carcinogenesis of HCC in young people. A total of 183 HBV-related HCC patients and 202 HBV carriers were therefore enrolled to compare serum viral loads in young (40 years of age) age groups. Other factors associated with the development of HCC were also analysed. The results showed that serum alanine aminotransferase (38.7 +/- 24.1 vs 58.4 +/- 65.4 IU/L, P = 0.006) and HBV DNA levels (log(10) titre: 4.20 +/- 1.33 vs 4.80 +/- 1.39, P = 0.053) were lower in young HCC patients than in old HCC patients. There was a positive correlation between age and serum HBV DNA level in HCC patients but a negative correlation in HBV carriers. Young HCC patients with HBV genotype B infection had higher viral loads than those with genotype C infection (log(10) titre: 4.79 +/- 1.34 vs 3.27 +/- 0.60, P = 0.001). By multivariate logistic regression analyses, high serum HBV DNA level was associated with the development of HCC in old patients [odds ratio (OR) 1.584, 95% confidence interval (CI) 1.075-2.333] rather than in young patients (OR 0.848, 95% CI 0.645-1.116). In conclusion, viral factors in association with the development of HBV-related HCC in young patients may be different from their old counterparts. The complicated interplay between host and virus could be responsible for the emergence and aggressive outcome of early-onset HCC.     

TLL1 variants do not predict hepatocellular carcinoma development in HCV cirrhotic patients treated with direct‐acting antivirals

Tolloid‐like 1 gene (TLL1) variant rs17047200 has been associated with hepatocellular carcinoma (HCC) in Japanese hepatitis C virus (HCV) patients with sustained virological response (SVR) to interferon or direct‐acting antiviral (DAA)‐based regimens. We investigated whether this holds true also in Caucasian cirrhotic patients cured by DAAs. Consecutive Caucasian HCV cirrhotics receiving DAA between December 2014 and December 2016 in a single centre were enrolled. Cirrhosis was defined histologically (METAVIR F4) or by liver stiffness measurement (LSM > 11.9 kPa). TLL1 rs17047200 was analysed by TaqMan SNP genotyping assay. 452 patients were enrolled: median age 63 (28‐87) years, 58% males, 47% HCV‐1b, LSM 19.1 (12.0‐75.0) kPa and Fibrosis‐4 (FIB‐4) score 4.9 (0.3‐46.0). 96% patients achieved an SVR. TLL1 genotype was AA in 329 (73%) and AT/TT in 123 (27%) (MAF = 0.14, HWE P > 0.05). Patients’ clinical features were similar across TLL1 genotypes. After 33 (3‐47) months from DAA start, 31 patients developed HCC, with a 3‐year estimated cumulative probability being 7.5% (95% CI: 5%‐10%). The cumulative incidence of HCC was 9% in TLL1 AA vs 7% in AT/TT patients (P = 0.55). Male sex (HR: 3.78, 95% CI: 1.4‐10.1, P = 0.008), diabetes (HR: 3.5, 95% CI: 1.68‐7.27, P = 0.001) and FIB‐4 (HR: 1.09, 95% CI: 1.03‐1.14, P = 0.001) were baseline‐independent predictors of HCC. The incidence of HCC was not influenced by TLL1 genotypes even when considering an additional group of 348 noncirrhotic patients, being 2% in AA vs 1% AT/TT patients (P = 0.58). In a large cohort of Caucasian HCV cirrhotics treated with DAA, TLL1 variants do not predict HCC development.     

Pathogenesis of hepatitis B and C-induced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is estimated to have an annual worldwide incidence of 0.25 to 1.2 million new cases per year. Both the prevalence and incidence of HCC vary markedly as a function of geography and the local prevalence of chronic viral hepatitis. Both chronic hepatitis B and chronic hepatitis C are recognized as risk factors for HCC. The prevalence of cirrhosis in individuals with HCC and chronic hepatitis B or C is reported to be 80.9% and 75.8%, respectively. HCC occurs at a lower rate in chronic viral hepatitis in the absence of cirrhosis. Moreover, hepatitis C virus (HCV) rather than hepatitis B virus (HBV) is associated with the majority of non-cirrhotic cases of HCC. It is probable that the ongoing process of hepatocyte necrosis and liver cell renewal coupled with inflammation, which is characteristic of chronic viral hepatitis, causes not only nodular regeneration and cirrhosis but also progressive genomic errors in hepatocytes as well as unregulated growth and repair mechanisms leading to hepatocyte dysplasia and, in some cases, hepatic carcinoma. Current concepts concerning virus-induced HCC are reported and discussed in the following review.