Polymerase chain reaction to detect hepatitis B virus DNA and RNA sequences in primary liver cancers from patients negative for hepatitis B surface antigen

Prevalence and genetic variability of occult hepatitis B virus in a human immunodeficiency virus positive patient cohort in Gondar, Ethiopia

BACKGROUND

Occult hepatitis B (OHB) is a major concern in HIV infected patients as it associates with a high risk of HBV reactivation and disease progression. However, data on the prevalence of OHB among HIV positive patients in Ethiopia is lacking. This study aims to determine the prevalence of OHB in HBV/HIV co-infected patients from Gondar, Ethiopia.

METHODS

A total of 308 consented HIV positive patients were recruited from the University of Gondar Teaching Hospital, Ethiopia. Clinical and demographic data of the participants were recorded. Plasma was tested for HBsAg and anti-HBc using commercial assays (Abbott Architect). In HBsAg negative anti-HBc positive patient samples, total DNA was isolated and amplified using nested PCR with primers specific to HBV polymerase, surface and pre-core/core regions, followed by Sanger sequencing and HBV mutational analysis using MEGA 7.0.

RESULTS

Of the total study subjects, 62.7% were female, median age 38.4 years, interquartile range (IQR): 18-68, and 208 (67.5%) had lifestyle risk factors for HBV acquisition. Two hundred and ninety-one study subjects were HIV+/HBsAg-, out of which 115 (39.5%) were positive for anti-HBc. Occult hepatitis B was detected in 19.1% (22/115) of anti-HBc positive HIV patients. HBV genotype D was the predominant genotype (81%) among OHB positive patients. Mutations associated with HBV drug resistance, HBV reactivation, and HCC risk were detected in 23% (5/22), 14% (3/22) and 45.5% (10/22) of patients, respectively.

CONCLUSION

This study found a high rate of occult hepatitis B in HIV patients. Further, high rates of mutations associated with HBV reactivation, drug resistance, and HCC risk were detected in these patients. These data highlighted the need for integrating OHB screening for proper management of liver diseases in HIV patients.

Molecular characterization of occult hepatitis B virus infection in patients with end-stage liver disease in Colombia

Background

Hepatitis B virus (HBV) occult infection (OBI) is a risk factor to be taken into account in transfusion, hemodialysis and organ transplantation. The aim of this study was to identify and characterize at the molecular level OBI cases in patients with end-stage liver disease.

Methods

Sixty-six liver samples were obtained from patients with diagnosis of end-stage liver disease submitted to liver transplantation in Medellin (North West, Colombia). Samples obtained from patients who were negative for the surface antigen of HBV (n = 50) were tested for viral DNA detection by nested PCR for ORFs S, C, and X and confirmed by Southern-Blot. OBI cases were analyzed by sequencing the viral genome to determine the genotype and mutations; additionally, viral genome integration events were examined by the Alu-PCR technique.

Results

In five cases out of 50 patients (10%) the criteria for OBI was confirmed. HBV genotype F (subgenotypes F1 and F3), genotype A and genotype D were characterized in liver samples. Three integration events in chromosomes 5q14.1, 16p13 and 20q12 affecting Receptor-type tyrosine-protein phosphatase T, Ras Protein Specific Guanine Nucleotide Releasing Factor 2, and the zinc finger 263 genes were identified in two OBI cases. Sequence analysis of the viral genome of the 5 OBI cases showed several punctual missense and nonsense mutations affecting ORFs S, P, Core and X.

Conclusions

This is the first characterization of OBI in patients with end-stage liver disease in Colombia. The OBI cases were identified in patients with HCV infection or cryptogenic cirrhosis. The integration events (5q14.1, 16p13 and 20q12) described in this study have not been previously reported. Further studies are required to validate the role of mutations and integration events in OBI pathogenesis.

Are current screening protocols for chronic hepatitis B virus infection adequate?

Chronic hepatitis B virus (HBV) infection screening usually includes only HBV surface antigen (HBsAg) testing; HBV core and surface antibody (anti-HBc, anti-HBs) assays, indicating resolved infection and immunity, are not routinely performed. Yet, serum HBV DNA is measurable in approximately 10% of HBsAg-negative/anti-HBc-positive cases, representing occult HBV infection (OBI). Patient blood samples from 2 Veterans Affairs medical center look-back investigations were screened for HBV infection using HBsAg enzyme immunoassays. Supplementary testing included anti-HBc and anti-HBs enzyme immunoassays. For anti-HBc-positive samples, HBV DNA testing was performed. Background OBI prevalence was further estimated at these 2 facilities based on HBV serology testing results from 1999-2012. Finally, a literature review was performed to determine OBI prevalence in the published literature. Of 1887 HBsAg-negative cohort patients, 98 (5.2%) were anti-HBc positive/anti-HBs negative; and 175 (9.3%), anti-HBc positive/anti-HBs positive. Six of 273 were HBV DNA positive, representing 0.3% of the total tested and 2.2% who were anti-HBc positive/anti-HBs negative or anti-HBc positive/anti-HBs positive. Among 32,229 general population veterans at these 2 sites who had any HBV testing, 4/108 (3.7%) were HBV DNA positive, none of whom were part of the cohort. In 129 publications with HBsAg-negative patients, 1817/1,209,426 (0.15%) had OBI. However, excluding blood bank studies with greater than 1000 patients, the OBI rate increased to 1800/17,893 (10%). OBI is not rare and has implications for transmission and disease detection. HBsAg testing alone is insufficient for detecting all chronic HBV infections. These findings may impact blood donation, patient HBV screening, follow-up protocols for patients assumed to have cleared the infection, and initiation of immunosuppression in patients with distant or undetected HBV.

Hepatitis B virus infection is associated with gastric cancer in China: an endemic area of both diseases

Background:

Hepatitis B virus (HBV) infection was demonstrated to be a risk factor of several cancers of the digestive system. In addition, liver cirrhosis, which could possibly result from chronic HBV infection, was associated with a higher risk of gastric cancer. However, the association of HBV infection and gastric cancer has not been investigated.

Methods:

A retrospective case–control study with 580 cases and 580 controls matched for age, sex and year of diagnosis was conducted. The associations between gastric cancer and HBV infection were explored with univariate and multivariate unconditional logistic regression analysis.

Results:

Hepatitis B surface antigen (HBsAg) was positively associated with gastric cancer (AOR (95% CI): 1.49 (1.06–2.10)). This association remained significant in patients without family history of gastric cancer (AOR (95% CI): (1.06–2.11)). For HBsAg-negative population, being anti-HBc positive/anti-HBs negative, which possibly indicated occult HBV infection, was also found to have some associations with gastric cancer. In addition, some synergistic effects between HBV infection and blood type A in gastric cancer were identified.

Conclusions:

The HBV infection was positively related with gastric cancer, especially for patients without family history of gastric cancer. Further prospective studies are warranted to confirm this relationship.

Hepatitis B virus-associated glomerulonephritis in HBsAg serological-negative patients

OBJECTIVE

The main objective of this study is to report the clinical and pathological characteristics of hepatitis B virus (HBV)-associated glomerulonephritis (HBV-GN) in serum hepatitis B surface antigen (HBsAg)-negative patients in China. HBV-GN is caused by the HBV's attack on the kidney tissues, but definitive diagnostic criteria are still lacking. The diagnostic criteria used in China require HBsAg positivity in the serum, but research on occult HBV infection has shown that HBV infection is also found in serum HBsAg-negative patients. Clinical and pathological characterization of HBV-GN in serum HBsAg-negative patients is required.

MATERIALS AND METHODS

Serologic and clinical findings and pathological characteristics of renal tissues in 18 HBV-GN patients (11 men and seven women) with serum HBsAg negativity were analyzed retrospectively. Thirty-three HBV-GN patients with serum HBsAg positivity and 59 patients with membranous nephropathy (MN) without any HBV infection markers in serum and renal tissues during the same period were included as controls.

RESULTS

Among the 18 HBsAg-negative patients with GN, 12 had HBsAb positivity in their sera. None of the patients was positive for serum HBeAg. Proteinuria was the major clinical manifestation and the renal histopathology was characterized as MN. Immune fluorescence deposits in renal tissues consisted mainly of HBsAg. The degree of renal injury and the decrease in the C3 level were less than those in HBsAg-positive patients and idiopathic membranous nephropathy patients.

CONCLUSION

We propose to use the HBV marker in renal tissues as a new diagnostic criterion for HBV-GN. If MN patients have HBV marker positivity in renal tissues, HBV-GN can be diagnosed even without HBsAg in the serum. This would improve the diagnostic accuracy and potential treatment efficiency.

Occult hepatitis B virus and hepatocellular carcinoma

Occult hepatitis B virus (HBV) infection (OBI) is a challenging pathobiological and clinical issue that has been widely debated for several decades. By definition, OBI is characterized by the persistence of HBV DNA in the liver tissue (and in some cases also in the serum) in the absence of circulating HBV surface antigen (HBsAg). Many epidemiological and molecular studies have indicated that OBI is an important risk factor for hepatocellular carcinoma (HCC) development. OBI may exert direct pro-oncogenic effects through the activation of the same oncogenic mechanisms that are activated in the course of an HBsAg-positive infection. Indeed, in OBI as in HBV-positive infection, HBV DNA can persist in the hepatocytes both integrated into the host genome as well as free episome, and may maintain the capacity to produce proteins-mainly X protein and truncated preS-S protein - provided with potential transforming properties. Furthermore, OBI may indirectly favor HCC development. It has been shown that the persistence of very low viral replicative activity during OBI may induce mild liver necro-inflammation continuing for life, and substantial clinical evidence indicates that OBI can accelerate the progression of liver disease towards cirrhosis that is considered the most important risk factor for HCC development.

Discrepancy between serological and virological analysis of viral hepatitis in hemodialysis patients

BACKGROUND AND AIM

Viral hepatitis is a health threat for hemodialysis (HD) patients and it may be transmitted during treatment. Some patients categorized to have viral hepatitis were found to be non-viremic. To clarify the discrepancy between the serological tests in HD patients, we conducted the study.

METHODS

A total of 1681 HD patients was included. Blood samples were analyzed for hepatitis B surface antigen (HBsAg) and anti-hepatitis C antibody (anti-HCV). Detection of hepatitis B virus (HBV) DNA and hepatitis C virus (HCV) RNA were performed in either HBsAg (+) or anti-HCV (+) samples. HBV DNA/HCV RNA was also measured in a subset of HBsAg (-) and anti-HCV (-) patients. Liver function tests were analyzed and compared with the serological and virological tests.

RESULTS

The serological tests showed that 230 patients (13.7%) were HBsAg (+) and 290 (17.3%) were anti-HCV (+). We were unable to detect HBV DNA in 97 of 230 (42.2%) HBsAg (+) patients, and HCV RNA could not be found in 76 of 290 (26.2%) anti-HCV (+) patients. In 167 HBsAg (-) patients, only one showed a trace amount of HBV DNA. None of 151 anti-HCV (-) patients showed detectable HCV RNA. The prevalence rate of viral hepatitis remains high in Taiwanese HD patients: 13.7% for HBV and 17.3% for HCV. However, virological analysis showed 42.2% non-viremic rate for HBsAg and 26.2% non-viremic rate for anti-HCV.

CONCLUSIONS

The findings might challenge the presently suggested principles of bed and machine dedication and the diagnosis of viral hepatitis in HD patients.

ABO blood type, diabetes and risk of gastrointestinal cancer in northern China

AIM: To explore the potential risk factors related to gastrointestinal cancer in northern China.

METHODS: A total of 3314 cases of gastrointestinal cancer (esophageal, gastric, pancreatic and biliary) and 2223 controls (including healthy individuals, glioma and thyroid cancer) were analyzed by case-control study. Multivariable logistic regression analysis was applied to evaluate the association between different cancers and hepatitis B surface antigen, sex, age, blood type, diabetes, or family history of cancer.

RESULTS: Type 2 diabetes was significantly associated with gastric, biliary and pancreatic cancer with an OR of 2.0-3.0. Blood type B was significantly associated with esophageal cancer [odd ratio (OR) = 1.53, 95% confidence interval (CI) = 1.10-2.14] and biliary cancer (OR = 1.49, 95% CI = 1.09-2.05). The prevalence of type 2 diabetes was significantly higher in gastric, biliary and pancreatic cancers compared with other groups, with ORs ranging between 2.0 and 3.0. Family history of cancer was strongly associated with gastrointestinal compared with other cancers.

CONCLUSION: Blood type B individuals are susceptible to esophageal and biliary cancer. Type 2 diabetes is significantly associated with gastric, biliary and especially pancreatic cancer.

Pathogenesis of occult chronic hepatitis B virus infection

Occult hepatitis B infection (OBI) is characterized by hepatitis B virus (HBV) DNA in serum in the absence of hepatitis B surface antigen (HBsAg) presenting HBsAg-negative and anti-HBc positive serological patterns. Occult HBV status is associated in some cases with mutant viruses undetectable by HBsAg assays; but more frequently it is due to a strong suppression of viral replication and gene expression. OBI is an entity with world-wide diffusion. The failure to detect HBsAg, despite the persistence of the viral DNA, is due in most cases to the strong suppression of viral replication and gene expression that characterizes this “occult” HBV infection; although the mechanisms responsible for suppression of HBV are not well understood. The majority of OBI cases are secondary to overt HBV infection and represent a residual low viremia level suppressed by a strong immune response together with histological derangements which occurred during acute or chronic HBV infection. Much evidence suggests that it can favour the progression of liver fibrosis and the development of hepatocellular carcinoma.

Occult HBV infection among Egyptian hepatocellular carcinoma patients

BACKGROUND

Occult HBV infection accelerates the progression of liver fibrosis, cirrhosis, and finally leading to hepatocellular carcinoma (HCC). This study analyzed the occult HBV-genotypes in HCC patients.

METHODS

To achieve our objective, matched serum and tissue samples were collected from 40 HCC patients. Three sets of primers were used for the HBV-DNA detection by nested-PCR, which cover the HBV-genome; Core, Surface and X genes. Genotyping system based on PCR using type-specific primers was applied on HBV-DNA positive samples.

RESULTS

Intrahepatic occult HBV-DNA was detected in 62.5%, whereas; Serum occult HBV-DNA were detected in only 22.5% of HCC patients. In patients' positive for both anti-HBs and anti-HBc, 10% had occult HBV in serum. In serologically negative HCV patients, 63% had intrahepatic HBV-DNA, and 21% had HBV-DNA in serum samples. HBV-genotype D (32%) and B (24%) attributed predominantly to intrahepatic HBV infections in HCC patients, whereas HBV-genotype A (4%) and C (8%) infections were the least observed.

CONCLUSION

This is the first study to show the genotypes of occult HBV infection in HCC Patients. We suggest that B or D may influence the outcome of HBV infection which may lead to the development of HCC.

Hepatocellular carcinoma in African Blacks: Recent progress in etiology and pathogenesis

Occult hepatitis B virus (HBV) infection was shown to be present in 75% of Black Africans with hepatocellular carcinoma (HCC) in whom the tumor was hitherto not thought to be caused by chronic HBV infection. The association between chronic HBV infection and the development of the tumor is thus even closer than was originally thought. HBV viral load was found to be significantly higher in patients with HCC than in Black African controls. As in other populations, HBV e antigen-positive patients with hepatocellular carcinoma had significantly higher viral loads than patients negative for this antigen. The significance of this finding is discussed. The risk for HCC development with genotype A of HBV, the predominant genotype in African isolates, has not been investigated. Genotype A was shown to be 4.5 times more likely than other genotypes to cause HCC in Black Africans, and tumours occurred at a significantly younger age. Increasing numbers of patients with human immunodeficiency virus (HIV) and HBV co-infection are being reported to develop HCC. A preliminary case/control comparison supports the belief that HIV co-infection enhances the hepatocarcinogenic potential of HBV. A study from The Gambia provides the first evidence that dietary exposure to aflatoxin B(1) may cause cirrhosis and that this may play a contributory role in the pathogenesis of aflatoxin-induced HCC. An animal model has provided experimental support for the clinical evidence that dietary iron overload in the African is directly hepatocarcinogenic, in addition to causing the tumor indirectly through the development of cirrhosis.

Risk factors for intrahepatic and extrahepatic cholangiocarcinoma: a case-control study in China

BACKGROUND/AIMS

The risk factors for cholangiocarcinoma are incompletely defined in China, especially for intrahepatic cholangiocarcinoma (ICC). We evaluated the risk factors for both ICC and extrahepatic cholangiocarcinoma (ECC).

METHODS

A case-control study in which cases were cholangiocarcinoma patients referred to Peking Union Medical College Hospital (PUMCH) between 1998 and 2008 and controls were healthy individuals. Controls were randomly selected from an existing database of healthy individuals at the Health Screening Center of PUMCH. Data on liver disease, family history, diabetes, smoking and drinking were collected by a retrospective review of the patients' records and health examination reports or by interview.

RESULTS

A total of 190 patients (61 ICC; 129 ECC) and 380 age- and sex-matched controls were enrolled. HBsAg (P<0.001) and anti-HBc without HBsAg (P=0.001) were significantly related to ICC. The adjusted odds ratios (OR) and 95% confidence intervals (CI) were 18.1 (95% CI: 7.5-44.0) and 3.6 (95% CI: 1.7-7.6) respectively. Diabetes mellitus (P=0.007), cholecystolithiasis (P=0.004) and previous cholecystectomy (P<0.001) were significantly associated with ECC. The prevalence of cirrhosis was higher in ICC than that in ECC (P<0.001). Furthermore, on excluding the ICC patients with cirrhosis, ICC patients showed significant independent associations with HBsAg (OR: 7.3; 95% CI: 3.1-17.2) and anti-HBc without HBsAg (OR: 2.4; 95% CI: 1.1-5.2).

CONCLUSION

Cirrhosis and chronic hepatitis B virus infection are risk factors for ICC, while cholecystolithiasis, diabetes and previous cholecystectomy are risk factors for ECC.

Liver cell transformation in chronic HBV infection

Epidemiological studies have provided overwhelming evidence for a causal role of chronic HBV infection in the development of hepatocellular carcinoma (HCC), but the molecular mechanisms underlying virally-induced tumorigenesis remain largely debated. In the absence of a dominant oncogene encoded by the HBV genome, indirect roles have been proposed, including insertional activation of cellular oncogenes by HBV DNA integration, induction of genetic instability by viral integration or by the regulatory protein HBx, and long term effects of viral proteins in enhancing immune-mediated liver disease. In this chapter, we discuss different models of HBV-mediated liver cell transformation based on animal systems of hepadnavirus infection as well as functional studies in hepatocyte and hepatoma cell lines. These studies might help identifying the cellular effectors connecting HBV infection and liver cell transformation.

Antibody to hepatitis B core antigen as a screening test for occult hepatitis B virus infection in Egyptian chronic hepatitis C patients

PURPOSE

The presence of hepatitis B virus (HBV) DNA in liver tissue and/or in serum in the absence of detectable hepatitis B surface antigen (HBsAg) is called occult HBV infection. This pattern was identified in patients with chronic hepatitis C virus (HCV) infection. The aim of this study was to determine the role of antibodies to hepatitis B core antigen (anti-HBc) as a screening test for occult HBV infection in Egyptian chronic HCV patients.

METHODS

One hundred chronic HCV patients negative for HBsAg were included and subdivided into two groups according to anti-HBc-IgG seroreactivity. Group A included 71 patients positive for anti-HBc (53 men and 18 women, mean age +/- SD 48.8 +/- 9.6 years), and group B included 29 patients negative for anti-HBc (18 men and 11 women, mean age +/- SD 46.6 +/- 11.7 years). All patients were subjected to full clinical assessment, routine laboratory investigations, abdominal ultrasonography and quantification of HBV-DNA by real-time PCR.

RESULTS

Chronic HCV patients positive for anti-HBc have more severe liver disease compared with anti-HBc negative patients. Although HBV-DNA in the serum was detected in 22.5% of anti-HBc-positive chronic HCV patients, it was not detected in any of anti-HBc-negative chronic HCV patients. There was no significant difference in any of the clinical and laboratory data tested between anti-HBc-positive patients with and without HBV-DNA in the serum.

CONCLUSION

A significant number of patients with anti-HBc had detectable levels of HBV-DNA in the serum. Egyptian chronic HCV patients have a high prevalence of occult HBV infection.

Hepatitis B: the virus and disease

Hepatitis B virus (HBV) infects more than 300 million people worldwide and is a common cause of liver disease and liver cancer. HBV, a member of the Hepadnaviridae family, is a small DNA virus with unusual features similar to retroviruses. HBV replicates through an RNA intermediate and can integrate into the host genome. The unique features of the HBV replication cycle confer a distinct ability of the virus to persist in infected cells. Virological and serological assays have been developed for diagnosis of various forms of HBV-associated disease and for treatment of chronic hepatitis B infection. HBV infection leads to a wide spectrum of liver disease ranging from acute (including fulminant hepatic failure) to chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Acute HBV infection can be either asymptomatic or present with symptomatic acute hepatitis. Most adults infected with the virus recover, but 5%-10% are unable to clear the virus and become chronically infected. Many chronically infected persons have mild liver disease with little or no long-term morbidity or mortality. Other individuals with chronic HBV infection develop active disease, which can progress to cirrhosis and liver cancer. These patients require careful monitoring and warrant therapeutic intervention. Extrahepatic manifestations of HBV infection are rare but can be difficult to diagnose and manage. The challenges in the area of HBV-associated disease are the lack of knowledge in predicting outcome and progression of HBV infection and an unmet need to understand the molecular, cellular, immunological, and genetic basis of various disease manifestations associated with HBV infection.

Prevalence and virological features of occult hepatitis B virus infection in female sex workers who work uncontrolled in Turkey

BACKGROUND

There is little information about the prevalence of occult hepatitis B virus infection (OHBVI). We have investigated the prevalence and virological features of OHBVI among female sex workers (FSWs) in Istanbul.

METHODS

Hepatitis B surface antigen (HBsAg) was tested in FSWs who work uncontrolled and were admitted to Venereal Diseases Hospital. HBV DNA and anti-HBs were investigated in all the HBsAg-negative cases. Hepatitis B envelope (HBe) antigen, anti-HBe, anti-hepatitis B core (HBc) antigen, HBV genotype, S gene and precore (PC)/basic core promoter (BCP) mutations were determined in HBV DNA-positive sera.

RESULTS

Two hundred and eighty-six volunteers were enrolled and 32.5% (n=93) of them had anti-HBs positivity. HBV DNA (range 30-209 copy/ml) was positive in 11 anti-HBs-negative and two anti-HBs-positive cases. The prevalence of OHBVI was 4.5% (13/286). Anti-HBc was positive in 77% (10/13) of those with OHBVI and anti-HBe positivity was 53.8% (7/13). Only genotype D was present in all occult HBV-infected cases. One PC (G1896A) and one BCP (T1762/A1764) mutation was found, but S gene mutation was not detected in any of the samples.

CONCLUSION

In this population, OHBVI may have a negligible role in the horizontal transmission because of a very low viral load, and PC and core promoter mutations are very rare.

[The significance of anti-HBc and occult hepatitis B virus infection in the occurrence of hepatocellular carcinoma in patients with HBsAg and anti-HCV negative alcoholic cirrhosis]

BACKGROUND/AIMS

Alcohol and the hepatitis B virus (HBV) exert synergistic effects in hepatocelluar carcinogenesis. We aimed to elucidate the clinical significance of the antibody to hepatitis B core antigen (anti-HBc) and occult HBV infection on the development of hepatocellular carcinoma (HCC) in patients with alcoholic liver cirrhosis (LC).

METHODS

Patients with alcoholic LC alone (n=193) or combined with HCC (n=36), who did not have HBsAg or antibody to hepatitis C virus were enrolled. Clinical data and laboratory data including anti-HBc were investigated at enrollment. The polymerase chain reaction was applied to HBV DNA using sera of patients with HCC or LC after age and sex matching.

RESULTS

Patients with HCC were older (60+/-11 years vs. 53+/-10 years, mean+/-SD, P<0.001), more likely to be male (100% vs. 89%, P=0.03), and had a higher positive rate of anti-HBc (91.2% vs. 77.3%, P=0.067), and a higher alcohol intake (739+/-448 kg vs. 603+/-409 kg, P=0.076) than those with LC. Age was the only significant risk factor for HCC revealed by multiple logistic regression analysis (odds ratio, 1.056; P=0.003). The positive rate of anti-HBc and alcohol intake did not differ in age- and sex-matched subjects between the LC (n=32) and HCC (n=31) groups. However, the detection rate of serum HBV DNA was higher in the HCC group (48.4%) than in the LC group (0%, P<0.001).

CONCLUSIONS

Anti-HBc positivity is not a risk factor for HCC. However, occult HBV infection may be a risk factor for HCC in patients with alcoholic LC.

Association between hepatitis B virus and pancreatic cancer

PURPOSE

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are considered to be hepatotropic and are a major cause of hepatocellular carcinoma. However, little is known about the role of HBV and HCV infection in other malignancies. This study aimed to determine whether HBV and HCV infections increase the risk for pancreatic cancer development.

PATIENTS AND METHODS

At The University of Texas M. D. Anderson Cancer Center, Houston, TX, we recruited 476 patients with pathologically confirmed adenocarcinoma of the pancreas and 879 age-, sex-, and race-matched healthy controls. Blood samples were tested for the presence of HCV antibodies (anti-HCV), HBV surface antigen (HBsAg), antibodies against HBV core antigen (anti-HBc), and antibodies against HBsAg (anti-HBs). The positive samples were retested by two confirmatory tests. An unconditional multivariable logistic regression analysis was used to estimate adjusted odds ratios (AORs).

RESULTS

Anti-HCV was positive in seven cases (1.5%) and nine controls (1%). Anti-HBc was positive in 36 cases (7.6%) and 28 controls (3.2%). The estimated AORs and 95% CIs were as follows: anti-HCV-positive, 0.9 (95% CI, 0.3 to 2.8), anti-HBc-positive, 2.5 (95% CI, 1.5 to 4.2), anti-HBc-positive/anti-HBs-positive, 2.3 (95% CI, 1.2 to 4.2), and anti-HBc-positive/anti-HBs-negative, 4 (95% CI, 1.4 to 11.1). Risk modification by past exposure to HBV was observed among diabetics (AOR, 7.1; 95% CI, 1.7 to 28.7).

CONCLUSION

Past exposure to HBV may be associated with pancreatic cancer development. Should such findings be confirmed by other studies, it may offer important insights into the etiology of pancreatic cancer and may suggest the need to consider prevention of HBV reactivation among patients with HBV-related pancreatic cancer during chemotherapy.

Occult hepatitis B virus infection in Southern African blacks with hepatocellular carcinoma

BACKGROUND AND AIM

To ascertain the prevalence of occult hepatitis B virus (HBV) infection in southern African blacks with hepatocellular carcinoma.

METHODS

Sera from 118 patients negative for HBV surface antigen but positive for HBV antibodies were studied. HBV-DNA was detected using a nested polymerase chain reaction (PCR) assay and confirmed by nucleotide sequencing of the surface and precore/core genes.

RESULTS

Surface gene HBV-DNA was detected in a single PCR assay in 48.4% of the patients. Positive results increased to 57.7% after two PCR assays (not significant) and 75.7% after four assays (P < 0.001). No false positive results were obtained in these assays or in the 15 control samples for which PCR assays were performed four times. Significant differences in positivity rates were not observed between patients positive for HBV core antibody alone and those positive for core and surface antibodies. The sensitivity of the PCR amplification of the precore/core gene was significantly less than that of the surface open reading frame: the yield of positive results was 23.7% after one assay, 32.2% after two assays (not significant), and 52% after four assays (P < 0.001). Combining the results of the assays of the two genes increased the yield of positive results for the first assay (by 11.9%, P = 0.015), but not the second (6.1%) or fourth assays (4.6%).

CONCLUSION

Occult HBV infection is present in the serum of the majority of hepatocellular carcinomas in southern African blacks whose serum is negative for hepatitis B surface antigen but positive for anti-HBV core antigen. The yield of positive results increases if more than one PCR assay is performed.

Occult hepatitis B virus and hepatitis C virus infections

Occult HBV infection is a well-recognised clinical entity characterised by the detection of HBV-DNA in serum and/or in liver in the absence of detectable hepatitis B surface antigen (HBsAg). Occult HBV infection has been described not only in patients who have resolved an acute or chronic HBV infection but also in patients without any serological markers of a past HBV infection. Occult HBV infection in patients with chronic HCV infection may induce more severe liver disease and lower response rate to interferon treatment. The existence of occult HCV infections has been also reported more recently. Occult HCV infection is characterised by the presence of HCV-RNA in liver and peripheral blood mononuclear cells in the absence of detectable serum HCV-RNA. Occult HCV infection may occur under two different clinical situations: in hepatitis C antibody-(anti-HCV) negative and serum HCV-RNA-negative patients with abnormal liver function tests and in anti-HCV-positive patients who have no detectable serum HCV-RNA and who have normal liver enzymes. The clinical relevance of occult HCV infections is still under investigation.

HBV genome integration and genetic instability in HBsAg-negative and anti-HCV-positive hepatocellular carcinoma in Japan

The aim of this study is to clarify the existence and the form of HCV RNA and HBV DNA genome integration and genetic instability in liver tissue with HBsAg-negative and anti-HCV-positive HCC. We investigated 16 Japanese patients with HBsAg-negative and anti-HCV-positive HCC. HBV genome integration into host cell genome by Southern hybridization and PCR was examined. Moreover, we analyzed loss of heterozygosity (LOH) and replication errors (RER) of chromosomes 2p, 3p and 17p using the PCR and an autosequencer to determine the three microsatellite regions D2S123, D3S1067, TP53. Eight (50.0%) of 16 were found to have integrated genome of HBV in tumor tissue (T) by PCR. In even the non-tumor regions (NT), seven patients (43.8%) were found to have HBV genome integration. The coincidence between T and NT was found in 4 (25%). Integration of HBV-X gene in T was revealed in three (18.7%), and HBV-integration was confirmed in all NT. No integration of the X gene alone was found in the liver tissue. Five (37.5%) of eight HBV DNA integrated cases simultaneously had HCV RNA minus strand. Concerning the genetic instability, RER were detected in two of 16 (12.5%). RER at 2p; D2S123 was observed in one of 16 (6.2%) and at 3p; D3S1067 was observed in one (6.2%). LOH at the D2S123 locus was observed in one of 12 tumors with heterozygosity (8.3%). There was no genetic instability (LOH or RER) of TP53 which was p53 locus on 17p in T. There was only one case of eight HBV DNA integrated cases (6.2%) with genetic instability of RER of 3p simultaneously in T. In conclusion, the majority of HBsAg-negative and anti-HCV-positive HCC liver tissue was found to have HCV-RNA and HBV DNA integration, and in some samples, HBV DNA integration and genetic instability were concurrently confirmed. It is speculated that multistep carcinogenesis may have been proposed for HCC oncogenetic progression.

Hepatocellular carcinoma: latest developments

PURPOSE OF REVIEW

This review primarily focuses on new developments in the field of hepatocellular carcinoma.

RECENT FINDINGS

Potential preventive strategies in the development of hepatocellular carcinoma are being recognized. Novel molecular markers identified may aid in the diagnosis of early hepatocellular carcinoma in patients with chronic hepatitis C virus. Prognostic information gained by preoperative tumor biopsy is being investigated. Treatment of early hepatocellular carcinoma with resection versus primary or salvage transplantation continues to be debated. Expansion of selection criteria beyond the Milan criteria appears feasible. The role of living donor liver transplantation in hepatocellular carcinoma will require further study to determine the risk of recurrence. Improvements in chemoembolization with drug eluting beads appear promising.

SUMMARY

Further insight into the pathogenesis of hepatocellular carcinoma will result in the continued evolution of our approach and management of the disease. Tailored therapies based on tumor biology are needed to improve treatment response and ultimately patient survival.

Hepatitis B virus DNA in liver tissue and risk for hepatocarcinogenesis in patients with hepatitis C virus-related chronic liver disease. A prospective study

AIMS

To prospectively study whether occult hepatitis B virus (HBV) infection can promote the development of hepatocellular carcinoma (HCC) in patients with hepatitis C virus (HCV)-related chronic liver disease. In addition, to evaluate the difference among HBV DNA-negative patients and patients with high and low HBV copy numbers.

METHODS

A total of 167 patients with HCV-related chronic liver disease without HBV surface antigen (HBsAg) were studied. HBV DNA in liver tissue was determined using polymerase chain reaction (PCR).

RESULTS

HBV DNA was detected in 9 of 167 patients (5.4%) by single PCR and in 25 patients (15.0%) by nested PCR. HCC developed in 12 of 167 patients (7.2%). Ten of 142 HBV DNA-negative patients (7.0%) and 2 of 9 patients with a high HBV copy number (22.2%) developed HCC, whereas none of 16 patients with a low HBV copy number developed HCC. The incidence rate of HCC in patients with a high HBV copy number was significantly higher than in HBV DNA-negative patients and patients with low HBV copy number.

CONCLUSION

A high amount of HBV DNA in liver tissue of HBsAg-negative patients with HCV-related liver disease might be associated with HCC development.

Occult hepatitis B virus infection in patients with chronic liver disease due to hepatitis C virus and hepatocellular carcinoma in Brazil

BACKGROUND

The prevalence and consequences of occult HBV infection in patients with chronic liver disease by HCV remain unknown.

AIMS

To evaluate the prevalence of occult HBV infection in a population of HCV-infected patients with hepatocellular carcinoma.

METHODS

The serum samples were tested for HBV DNA by nested PCR and liver tissue analysis was carried out using the immunohistochemical technique of 66 HBsAg-negative patients: 26 patients with chronic hepatitis by HCV (group 1), 20 with hepatocellular carcinoma related to chronic infection by HCV (group 2) and 20 with negative viral markers for hepatitis B and C (control group).

RESULTS

Occult HBV infection was diagnosed in the liver tissue of 9/46 (19.5%) HCV-infected patients. Prevalence of occult B infection was evaluated in the HCV-infected patients with and without hepatocellular carcinoma, and there were seven (77.7%) of whom from group 2, conferring a 35% prevalence of this group. No serum sample was positive for HBV DNA in the three groups.

CONCLUSION

Occult infection B is frequently detected in liver tissue of HCV-infected patients, especially in cases of hepatocellular carcinoma. However large studies are needed to confirm that co-infection could determine a worse progress of chronic liver disease in this population.

Persistent occult hepatitis B virus infection: Experimental findings and clinical implications

Hepatitis B virus (HBV) is a highly pathogenic virus that causes chronic liver diseases in millions of people globally. In addition to a symptomatic, serologically evident infection, occult persistent HBV carriage has been identified since nucleic acid amplification assays of enhanced sensitivity became introduced for detection of hepadnaviral genomes and their replicative intermediates. Current evidence indicates that occult HBV infection is a common and long-term consequence of resolution of acute hepatitis B. This form of residual infection is termed as secondary occult infection (SOI). The data from the woodchuck model of HBV infection indicate that exposure to small amounts of hepadnavirus can also cause primary occult infection (POI) where virus genome, but no serological makers of exposure to virus, are detectable, and the liver may not be involved. However, virus replicates at low levels in the lymphatic system in both these forms. We briefly summarize the current understanding of the nature and characteristics of occult hepadnaviral persistence as well as of its documented and expected pathological consequences.

Frequency and significance of hepatitis B virus surface gene variant circulating among 'antiHBc only' individuals in Eastern India

BACKGROUND

Genetic mutation might account for the presence of hepatitis B virus (HBV) DNA among antiHBc only individuals. The aim of the study was to assess the prevalence and significance of surface gene mutations among antiHBc only cases in our population.

METHODS

Three hundred and three antiHBc(+) sera of adults (mean age, 33.7+/-11.0; range 18-65 years) as well as HBsAg(+)/HBV DNA(+) (n=19) controls were included in this study. Surface gene and basal core promoter (BCP)-precore region were amplified and surface gene was analyzed after direct sequencing.

RESULTS

One hundred and seventy-eight out of 303 (58.8%) was antiHBc only, 39/171 (22.8%) of them was HBV DNA(+). Genotypes A, C, D were found among both HBsAg(+) and antiHBc(+) samples. Single or multiple amino acids substitutions were found in 82% samples, however, G145R vaccine escape mutation was rare. Individuals having substitutions within as well as outside major hydrophilic loop (MHL) region were detected; some of these mutations were in overlapping RT domain of polymerase (Pol) gene.

CONCLUSIONS

The existence of occult HBV infection among antiHBc only individuals could not be explained fully by mutations in the 'a' determinant region of surface gene in our population.

Pathogenesis of hepatitis B virus-associated hepatocellular carcinoma

Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) remains the most common form of HCC in large areas of Asia and Africa. It remains common even in some countries where hepatitis C virus (HCV)-associated HCC has become the predominant form, such as Japan. Integration of HBV in HCC DNA is found at random sites in the host genome in nearly all patients with HBV-associated HCC. It is not clear how often this integration results in insertional mutagenesis, but previously unknown growth regulating genes and cancer-associated genes have been found frequently near HBV integration sites in HCC in recent studies. In addition, HBV encodes a transactivating protein, the X protein, which could enable the randomly integrated HBV to alter the function of host genes that are not near the integration site. Mutations at two adjacent codons in HBV (1762(T)/1764(A) mutations) within the X gene are frequently found in HCC patients, and may play a role in the mutagenic or transactivational role of HBV in HCC. The presence of cirrhosis in most patients with HBV-associated HCC, and the presence of mutations in tumor suppressor genes in many, suggests that these are also factors in hepatocarcinogenesis. Few studies have examined the mutations of more than one gene in the same HCC patients. Fewstudies have evaluated the interactions between HBV mutations, host gene mutations, cirrhosis, and other potentially mutagenic stresses at the cellular level, with progression to HCC, and few studies have been conducted to determine whether these changes must accumulate in succession to lead to HCC. The recent availability of rapid sequencing methods and DNA microarray technologies has permitted expression profiling and permutation analysis of an array of genes to explore the pattern and succession of molecular changes leading to HBV-associated HCC. To date, these methods have been used to show patterns of molecular changes that differ in HBV-associated HCC (compared to HCV-associated HCC or to HCC in patients lacking either virus) and patterns that can predict survival (and hence may directly indicate different mechanisms of disease), and may soon make possible a universally accepted clinical classification scheme for HCC.

Risk factors for intrahepatic and extrahepatic cholangiocarcinoma: a hospital-based case-control study

BACKGROUND

The risk factors for cholangiocarcinoma are poorly defined in the United States. We evaluated hepatitis C virus (HCV), hepatitis B virus (HBV), and liver cirrhosis as risk factors for intrahepatic cholangiocarcinoma (ICC) and extrahepatic cholangiocarcinoma (ECC).

METHODS

A case-control study in which cases were cholangiocarcinoma patients referred to the M.D. Anderson Cancer Center between 1992 and 2002 and controls were healthy individuals. Information about liver diseases, family history, diabetes, smoking, and alcohol consumption were collected on both groups. Blood from all participants was tested for HBV and HCV markers.

RESULTS

We identified 246 cases (83 ICC and 163 ECC) and matched them to 236 controls. Compared with controls, ICC patients had a higher prevalence of anti-HCV antibodies (6.0%vs 0.8%, P=0.01), anti-HBc (9.6%vs 0%, P<0.0001), and heavy alcohol consumption (21.7%vs 3.8%, P<0.0001). The adjusted odds ratio and 95% confidence interval (CI) were 7.9 (95% CI 1.3-84.5), 28.6 (95% CI 3.9-1,268.1), and 5.9 (95% CI 2.1-17.4), respectively. Only heavy alcohol consumption was higher in patients with ECC than in controls (17.8%vs 3.8%, P=0.003). The prevalence of diabetes and smoking were not significantly different between cases (ICC or ECC) and controls. The prevalence of cirrhosis was higher in patients with ICC than those with ECC (24.1%vs 4.9%, P<0.0001).

CONCLUSIONS

Liver cirrhosis and chronic HCV infection are possible risk factors for ICC but not ECC. Heavy alcohol consumption is a risk factor for both ICC and ECC.

Occult hepatitis B virus infection

The persistence of hepatitis B virus (HBV) genomes in HBV surface antigen (HBsAg) negative individuals is termed occult HBV infection. Occult HBV status is associated in some cases with mutant viruses undetectable by HBsAg assays, but more frequently it is due to a strong suppression of viral replication and gene expression. Occult HBV infection is an entity with world-wide diffusion, although the available data of prevalence in various categories of individuals are often contrasting because of the different sensitivity and specificity of the methods used for its detection in many studies. Occult HBV may impact in several different clinical contexts, including the transmission of the infection by blood transfusion or organ transplantation and its acute reactivation when an immunosuppressive status occurs. Moreover, much evidence suggests that it can favour the progression of liver fibrosis and above all the development of hepatocellular carcinoma.

Clinical characteristics and surgical outcome in hepatocellular carcinoma without hepatitis B virus surface antigen or hepatitis C virus antibody

OBJECTIVE

We investigated clinical characteristics and surgical outcome of hepatocellular carcinoma in association with hepatitis viral status. No consensus exists concerning differences in surgical outcome in patients with hepatocellular carcinoma according to viral hepatitis status, especially those negative for hepatitis B virus surface antigen and antibody to hepatitis C virus.

METHODS

Clinicopathologic data were available for 39 hepatectomy patients with hepatocellular carcinoma who were negative for hepatitis B virus surface antigen and hepatitis C virus antibody. Clinical characteristics and surgical outcome were analyzed retrospectively and compared to those patients with positive hepatitis viral markers.

RESULTS

Patients negative for viral hepatitis markers were more likely to have large, advanced-stages tumors with relatively well-preserved liver function and had a lower incidence of intrahepatic recurrences (P = 0.009). The intrahepatic recurrence rate reached a plateau at approximately 3 years after resection in patients with negative viral markers, while it continued to increase steadily in patients positive for viral hepatitis markers. By multivariable analysis, the absence of viral hepatitis markers predicted a decreased rate of intrahepatic recurrence (relative risk, 0.222; P = 0.001).

CONCLUSIONS

Adequate surgical resection in hepatocellular carcinoma patients negative for viral markers offers a good survival benefit, regardless of the etiology of the hepatocellular carcinoma.

Occult hepatitis B virus infection and cryptogenic chronic hepatitis in an area with intermediate prevalence of HBV infection

AIM: To assess the possible role of occult HBV infection in the pathogenesis of chronic hepatitis in Iranian patients.

METHODS: After exclusion of autoimmune, metabolic and viral etiologies, 104 consecutive adult patients with histologic and biochemical features of chronic hepatitis and negative HBsAg were enrolled in the study. Qualitative PCR with a sensitivity of 150 × 10³ copies/L, using two primers for Pre-S and core regions was applied to measure presence of HBV DNA in serum of the patients.

RESULTS: All 104 patients completed the study. Qualitative HBV DNA was positive in two patients (1.9%).

CONCLUSION: Occult HBV infection has negligible role in the pathogenesis of cryptogenic chronic hepatitis in Iranian patients.

Prevalence of occult HBV infection in haemodialysis patients with chronic HCV

AIM: To study the prevalence and clinical effects of occult HBV infection in haemodialysis patients with chronic HCV.

METHODS: Fifty chronic hemodialysis patients with negative HbsAg, and positive anti-HCV were included in the study. These patients were divided into two groups: HCV-RNA positive and HCV-RNA negative, based on the results of HCV-RNA PCR. HBV-DNA was studied using the PCR method in both groups.

RESULTS: None of the 22 HCV-RNA positive patients and 28 HCV-RNA negative patients revealed HBV-DNA in serum by PCR method. The average age was 47.2 ± 17.0 in the HCV-RNA positive group and 39.6 ± 15.6 in the HCV-RNA negative group.

CONCLUSION: The prevalence of occult HBV infection is not high in haemodialysis patients with chronic HCV in our region. This result of our study has to be evaluated in consideration of the interaction between HBsAg positivity (8%-10%) and frequency of HBV mutants in our region.

Epidemiology of HBV infection in Asian blood donors: Emphasis on occult HBV infection and the role of NAT

Hepatitis B virus (HBV) infection is endemic in many Asian countries. Among many transmission routes, transfusion is the one that should be prevented. The first major success in enhancing transfusion safety came with the implementation of hepatitis B surface antigen (HBsAg) in the early 1970s. However, the studies quoted in this review demonstrate that transmission by blood components negative for HBsAg can still occur in the acute phase of infection during the seronegative window period, or during chronic stages of infection (i.c. "occult" HBV infection, OHB). OHB is defined as the presence of HBV DNA in blood or liver tissues in patients negative for HBsAg, with or without any HBV antibodies. Because of limitations in current blood screening practices, OHB is an overlooked source of HBV transmission. For policy development on screening for HBV infection in blood donors, it would be useful to assess the relative contribution of the above two sources of transfusion-transmitted HBV infection from HBsAg-negative donations. New screening policy should be evaluated on the basis of available data or newly designed studies. While anti-HBc screening can climinate residual risk of occult HBV transmission by transfusion in low-endemic areas, it would not be practical in most parts of the world where the prevalence of anti-HBc is >10% as too many otherwise healthy donors will be ineligible. On the contrary, studies mentioned in this paper indicate that nucleic acid amplification test (NAT) or new HBsAg tests of enhanced sensitivity would be effective in the screening of blood donors for OHB in highly endemic countries. However, the cost-effectiveness of blood screening tests is a major concern in Asia. We therefore have systemically reviewed the literature on prevalence and infectivity of OHB in Asian countries and the possible role of NAT for identifying blood donors in the pre-HBsAg window phase or in later stages of OHB.

Clinical impact of occult HBV infections

HBV infection in the absence of HBsAg has been a matter of debate for years, but its existence and clinical relevance are now supported by many publications, editorials and reviews. HBV DNA without HBs antigenemia was detected in the following clinical situations: (1) Chronic, presumably viral, hepatitis unrelated to HCV, atypical alcoholic hepatitis and hepatocellular carcinoma (HCC); (2) viral reactivation following immunosuppression; (3) Transmission through transplantation, transfusion or experimental transmission to chimpanzees. Occult HBV infections are not restricted to areas of high HBV endemicity. Indeed, such cases have been described in Western countries including France. It is now established that occult HBV infection among non-HCV patients suffering from chronic hepatitis varies from 20% to 30% in Europe, and in the context of HCV infection it varies from 20% in France up to 80% in Japan. The percentage of occult HBV infections among non A-E cases depends on several parameters: (1) The method of detection, including PCR primer selection; (2) patient recruitment; (3) patients from countries highly endemic for HBV are more likely to develop occult HBV infections; (4) prevalence may also vary depending on the nature of biological material tested, with a higher proportion for liver compared to serum specimen. The mechanisms leading to HCC in occult HBV infection seem similar to those overt cases, patients with low-grade but diagnosable HBV replication that retains its pro-oncogenic properties. During the course of HCV infection, occult HBV infection may worsen liver damage induced by HCV and reduce the response to HCV antiviral treatment. Occult HBV infection is a frequent phenomenon and HBV DNA testing with highly sensitive PCR in the clinical setting is therefore becoming of paramount importance.

Prevalence of occult HBV infection among subjects with normal serum ALT levels in Korea

OBJECTIVE

To investigate the prevalence of occult HBV infection among subjects with normal serum ALT levels in South Korea.

METHODS

A total of 195 serum samples were collected from subjects without a past history of alcohol abuse and with normal serum ALT levels. They were negative for HBsAg, anti-HCV, and anti-HIV. HBV-DNA was detected from sera by nested polymerase chain reaction (PCR) using specific primers of the surface antigen region of the HBV genome. We performed a quantitation assay using hybrid capture II test to determine the levels of serum HBV-DNA.

RESULTS

HBV-DNA was detected in 31 of 195 subjects (16%). Prevalence of occult hepatitis B was significantly higher in the male subjects (23%) than in the female (8%), (P<0.05). We were able to detect HBV-DNA in 15% (7/47) even in which sera were all negative for anti-HBs and IgG anti-HBc. Serum HBV-DNA levels were as high as 10(5) copies/mL in 18 of 31 subjects (58%) with occult HBV infection.

CONCLUSIONS

The prevalence of occult HBV infection and their HBV-DNA levels were significantly high among subjects with normal serum ALT levels in South Korea. Thus, more meticulous attention should be given to prevent HBV transmission by blood transfusion or organ transplantation in endemic areas, and further studies on clinical implication and mechanism of occult HBV infection are required.

Serological pattern “anti-HBc alone”: Characterization of 552 individuals and clinical significance

AIM: To investigate the prevalence and clinical significance of “anti-HBc alone” in an unselected population of patients and employees of a university hospital in southern Germany.

METHODS: All individuals with the pattern “anti-HBc alone” were registered over a time span of 82 mo. HBV-DNA was measured in serum and liver samples, and clinical charts were reviewed.

RESULTS: Five hundred and fifty two individuals were “anti-HBc alone” (of 3004 anti-HBc positive individuals; 18.4%), and this pattern affected males (20.5%) more often than females (15.3%; P < 0.001). HBV-DNA was detected in serum of 44 of 545 “anti-HBc alone” individuals (8.1%), and in paraffin embedded liver tissue in 16 of 39 patients tested (41.0%). There was no association between the detection of HBV genomes and the presence of biochemical, ultrasonic or histological signs of liver damage. Thirty-eight “anti-HBc alone” patients with cirrhosis or primary liver carcinoma had at least one additional risk factor. HCV-coinfection was present in 20.4% of all individuals with “anti-HBc alone” and was the only factor associated with a worse clinical outcome.

CONCLUSION: In an HBV low prevalence area, no evidence is found that HBV alone causes severe liver damage in individuals with “anti-HBc alone”. Recommendations for the management of these individuals are given.

Hepatitis C -- identifying patients with progressive liver injury

Hepatitis C follows a variable course with some patients developing progressive liver fibrosis, cirrhosis and hepatocellular carcinoma, while others have minimal or no significant liver disease after decades of infection. Studies have identified both host and viral factors associated with disease progression. The importance of general factors such as age at infection, gender, immune status and alcohol consumption has long been recognized; however recently, polymorphisms in a wide array of genes have also been shown to be associated with progressive fibrosis. How specific viral proteins may contribute to disease progression has also been studied. This review highlights what is currently known about the factors associated with progressive liver injury in patients with hepatitis C. A greater understanding of the determinants of disease progression will hopefully lead to improved utilization of existing treatments and ultimately may aid in identification of new therapeutic targets.

Occult hepatitis B virus infection is associated with the development of hepatocellular carcinoma in chronic hepatitis C patients

BACKGROUND

Occult hepatitis B virus (HBV) infection frequently occurs in patients with HBV surface antigen (HBsAg)-negative chronic liver disease, and much evidence suggests that it is a risk factor for hepatocellular carcinoma (HCC) development. However, to the authors' knowledge, no follow-up study has been performed to date evaluating HCC occurrence over time in chronic hepatitis patients with or without occult HBV infection.

METHODS

A cohort of the 380 HBsAg-negative chronic hepatitis patients attending the study institution between 1991-2000 were evaluated and tested for occult HBV DNA by analysis of liver biopsy specimens.

RESULTS

There were 135 patients (35.5%) with occult HBV and 245 patients (64.5%) without occult HBV. Cirrhosis was significantly associated with occult HBV infection (P = 0.01). One hundred thirty-four of these patients were followed for a minimum of 50 months (median, 82.8 +/- 32.6 mos). Fifty-three patients (39%) were occult HBV carriers and 81 (61%) were not. Nine patients developed HCC during the follow-up; eight were positive and one was negative for occult HBV (P = 0.002).

CONCLUSIONS

The current observational cohort study showed that, among the HBsAg-negative patients with chronic hepatitis, HCC develops for the most part in carriers of occult HBV. Therefore, the evaluation of HBV genomes in chronic hepatitis patients appears to be a powerful tool for the identification of individuals at higher risk of HCC development.

The global health burden of infection-associated cancers in the year 2002

Several infectious agents are considered to be causes of cancer in humans. The fraction of the different types of cancer, and of all cancers worldwide and in different regions, has been estimated using several methods; primarily by reviewing the evidence for the strength of the association (relative risk) and the prevalence of infection in different world areas. The estimated total of infection-attributable cancer in the year 2002 is 1.9 million cases, or 17.8% of the global cancer burden. The principal agents are the bacterium Helicobacter pylori (5.5% of all cancer), the human papilloma viruses (5.2%), the hepatitis B and C viruses (4.9%), Epstein-Barr virus (1%), human immunodeficiency virus (HIV) together with the human herpes virus 8 (0.9%). Relatively less important causes of cancer are the schistosomes (0.1%), human T-cell lymphotropic virus type I (0.03%) and the liver flukes (0.02%). There would be 26.3% fewer cancers in developing countries (1.5 million cases per year) and 7.7% in developed countries (390,000 cases) if these infectious diseases were prevented. The attributable fraction at the specific sites varies from 100% of cervix cancers attributable to the papilloma viruses to a tiny proportion (0.4%) of liver cancers (worldwide) caused by liver flukes.

Genotypic variability of hepatitis viruses associated with chronic infection and the development of hepatocellular carcinoma

At least five hepatitis viruses are known to date. Infection by enterically transmitted viruses (HAV and HEV) is generally benign compared with the disease caused by parenterally transmitted viruses (HBV, HCV, and HDV). Chronic infection by HBV is common and may evolve to cirrhosis and hepatocellular carcinoma (HCC). Eight HBV genotypes (A-H) have been described, with the South American genotype F being the most divergent. Seven clades of HDV have been described; among them, the South American genotype III is associated to a high frequency of fulminant hepatitis. HCV infection leads to a high rate of chronicity and HCC. From the six HCV genotypes, infection with genotype 1 might have the worst prognostic. Chronic infection by HCV and HBV is the major risk factor for HCC, which occurs, in the majority of the cases, as a consequence of cirrhosis. However, there is growing evidence that some HBV and HCV proteins might contribute to the generation of HCC. Some HBV and HCV variants and specific mutations within the viral genomes might be more frequently associated with the evolution to HCC. Although more studies are needed, emerging evidence indicates that it might be important to address the genetic variability of these viruses and their contribution to the development of HCC.