A nested case-control study on association between hepatitis C virus antibodies and primary liver cancer in a cohort of 9,775 men in Taiwan

A prospective cohort study of cigarette smoking, alcohol drinking and liver cancer incidence in Chinese men

OBJECTIVES

Population-based prospective studies on the associations of cigarette smoking, alcohol drinking, and primary liver cancer remain limited in Mainland China. Our study was designed to evaluate such relationships in middle-aged Chinese men.

METHODS

Self-reported habits of cigarette smoking and alcohol drinking were obtained from all cohort members at the baseline survey. The outcomes were identified through in-person follow-up and annual record linkage to multiple statistics of vital and cancer registration. Age-adjusted and multivariable-adjusted hazard ratio (HR) and their corresponding 95% confidence interval (CI) were estimated utilizing the Cox regression model.

RESULTS

After a median follow-up of 12.31 years, 329 cases of incident primary liver cancer occurred among 45 266 male participants. Compared with never smoker, former smoker was positively associated with liver cancer risk, with a multivariable-adjusted HR of 1.42 (95% CI 1.02-1.98). Individuals who had smoked for more than 40 years had a 49% increased risk of liver cancer (HR≥40 years  1.49, 95% CI 1.04-2.14). The association of alcohol drinking with liver cancer showed no statistical significance.

CONCLUSIONS

Our study provided evidence that cigarette smoking was positively associated with an increased liver cancer risk among Chinese men. Attention to such non-viral modifiable risk factors to prevent liver cancer effectively is needed.

Current Perspective of Plant-Based Diets on Communicable Diseases Caused by Viruses: A Mini Review

Communicable diseases are illnesses caused by pathogenic biological agents, including viruses, bacteria, fungi, parasites, and protozoa. Such diseases spread among people through contact with contaminated surfaces, bodily fluids, or blood products, or through the air, insect bites, or consuming contaminated food and beverages. Although some communicable diseases can be treated or prevented by taking medication and vaccines, there has been an increase in awareness of adopting a healthy diet to aid in the prevention and reversal of these diseases. One popular diet is a plant-based diet. Plant-based diets generally consist of vegetables, grains, nuts, seeds, legumes, and fruits, without any animal-source foods or artificial ingredients. Over the years, this diet has continuously increased in popularity. Reasons for following a plant-based diet are varied but include health benefits, such as improving immunity, and reducing the risk of heart disease, diabetes, and some cancers. Scientific evidence even shows that just an increased vegetable intake can decrease the occurrence of chronic diseases caused by viruses, such as hepatitis viruses, and reduce the risk of severe coronavirus disease 2019. Therefore, this mini review discusses the effectiveness of adopting a plant-based diet in ameliorating diseases caused by selected viruses and its limitations.

Interaction between tobacco smoking and hepatitis B virus infection on the risk of liver cancer in a Chinese population

Although tobacco smoking has been reported as a risk factor for liver cancer, few studies have specifically explored the association among Chinese females and the potential interaction between smoking and other risk factors. A population-based case-control study was conducted and 2,011 liver cancer cases and 7,933 healthy controls were enrolled in Jiangsu, China from 2003 to 2010. Epidemiological data were collected, and serum hepatitis B surface antigen (HBsAg) and anti-HCV antibody were measured. Unconditional logistic regression was used to examine association and potential interaction, while semi-Bayes (SB) method was employed to make estimates more conservative. The prevalence of serum HBsAg positivity was 43.2% among cases and 6.5% among controls. The adjusted odds ratios (OR) for ever smoking were 1.62 (95% confidence interval [CI]: 1.33-1.96) among male and 0.82 (95% CI: 0.53-1.26) among female. Age at first cigarette, duration of smoking and pack-years of smoking were all significantly associated with liver cancer among men. Compared to HBsAg-negative never smokers, the adjusted ORs were 1.25 (95% CI: 1.03-1.52) for HBsAg-negative ever smokers, 7.66 (95% CI: 6.05-9.71) for HBsAg-positive never smokers, and 15.68 (95% CI: 12.06-20.39) for HBsAg-positive ever smokers. These different odds ratios indicated super-additive (RERI: 7.77, 95% CI: 3.81-11.73) and super-multiplicative interactions (ROR: 1.64, 95% CI: 1.17-2.30) between hepatitis B virus (HBV) infection and tobacco smoking. Most associations and interactions detected remained statistically significant after SB adjustments. Tobacco smoking and HBV infection positively interact in the development of liver cancer.

Recognition criteria for occupational cancers in relation to hepatitis B virus and hepatitis C virus in Korea

The goal of this study was to review the scientific basis for the recognition of occupational cancer, in relation to hepatitis viral infections in Korea. Most Hepatitis B virus (HBV) infections in Korea occur as vertical infections, but these are decreasing rapidly due to vaccination. Hepatitis C virus (HCV) is known to be transmitted through parenteral routes, but the transmission route is often unclear. Most occupational infections of hepatitis virus involve accidental injuries of medical institution workers while using virus-contaminated medical devices. Many cohort studies and case-control studies have consistently reported that HBV and HCV infection increases the risk of hepatocellular carcinoma (HCC) and the strength of this association is high. Non-Hodgkin’s lymphoma appears to be associated with HCV. Cholangiocarcinoma, pancreatic cancer, leukemia, and thyroid cancer are considered to be less related or unrelated to epidemiological causation. There are no uniform international specific criteria for occupational cancer caused through occupational exposure to a hepatitis virus. In establishing appropriate standards applicable to Korea, there should be sufficient consideration of latency, virus exposure levels and frequency, and other cancers, apart from HCC.

In conclusion, we recommend keeping the current specific criteria. However, if a worker is injured at work when using a sharp medical device, and HBV and HCV viral infections are confirmed through serologic tests; if the worker is diagnosed as having a chronic HBV or HCV infection, a subsequent HCC (or Non-Hodgkin’s lymphoma following chronic HCV infection) can then be considered highly related to the worker’s occupation.

Alcohol consumption and liver cancer risk: a meta-analysis

PURPOSE

Alcohol is a confirmed risk factor of liver cancer. Yet, its dose-response function and synergistic effects with other risk factors remain unclear.

METHODS

We performed a meta-analysis on publications up to May 2014. A total of 112 publications were identified. The meta-relative risk (mRR) and the dose-response trend were calculated. Tests for heterogeneity, publication bias, and sensitivity analyses were performed. The synergy index (SI) was recorded or calculated, whenever possible.

RESULTS

Compared to individuals who never drank or drank at very low frequencies, the mRR for ever drinkers was 1.29 (95% confidence interval, CI 1.16-1.42) and 1.46 (95% CI 1.27-1.65) for case-control studies, and 1.07 (95% CI 0.87-1.27) for cohort studies. Being a current drinker was associated with an increased liver cancer risk in case-control studies (mRR = 1.55, 95% CI 0.38-2.73), but not in cohort studies (mRR = 0.86, 95% CI 0.74-0.97). The dose-response relation between alcohol and liver cancer was apparent with RR = 1.08 (95% CI 1.04-1.11) for 12 g/day (~1 drink), 1.54 (95% CI 1.36-1.74) for 50 g/day, 2.14 (95% CI 1.74-2.62) for 75 g/day, 3.21 (95% CI 2.34-4.40) for 100 g/day, and 5.20 (95% CI 3.25-8.29) for 125 g/day of alcohol consumption. There were synergistic effects of alcohol consumption with hepatitis (S = 2.14, 95% CI 1.31-2.98) and with diabetes (S = 3.57, 95% CI 2.29-4.84) on the risk of liver cancer, although this may be subject to publication bias.

CONCLUSION

Overall, one alcoholic drink per day (~12 g/day) may be associated with a 1.1 times higher liver cancer risk. Further studies on the synergistic effects of alcohol consumption and other major risk factors are warranted.

Geographic patterns of hepatocellular carcinoma mortality with exposure to iron in groundwater in Taiwanese population: an ecological study

BACKGROUND

Many studies have examined the risk factors for HCC (including hepatitis B virus, hepatitis C virus, aflatoxin, retinol, cigarette smoking, and alcohol consumption). However, data from previous studies on the association between iron exposure, land subsidence, and HCC mortality/incidence were limited, especially in Taiwanese population. We aimed to explore the geographical distribution of HCC mortality rates by township-specific data and to evaluate the association between HCC mortality, land subsidence, and iron levels in groundwater in Taiwan.

METHODS

We conducted an ecological study and calculated the HCC age-standardized mortality/incidence rates according to death certificates issued in Taiwan from 1992 to 2001 and incidence data from 1995-1998. The land subsidence dataset before 2005 and iron concentrations in groundwater in 1989 are also involved in this study. Both geographical information systems and Pearson correlation coefficients were used to analyze the relationship between HCC mortality rates, land subsidence, and iron concentrations in groundwater.

RESULTS

Township-specific HCC mortality rates are higher in southwestern coastal townships where serious land subsidence and higher township-specific concentrations of iron in groundwater are present. The Pearson correlation coefficients of iron concentrations in groundwater and ASRs of HCC were 0.286 (P = 0.004) in males and 0.192 (P = 0.058) in females for mortality data; the coefficients were 0.375 (P < 0.001) in males and 0.210 (P = 0.038) in females for incidence data.

CONCLUSIONS

This study showed that HCC mortality is clustered in southwestern Taiwan and the association with the iron levels in groundwater in Taiwanese population warrant further investigation.

Lifetime risk and sex difference of hepatocellular carcinoma among patients with chronic hepatitis B and C

PURPOSE

Both hepatitis B (HBV) and C viruses (HCV) are causes of hepatocellular carcinoma (HCC), but lifetime risk and sex difference remain unclear. This study aimed to assess the lifetime risk and sex difference of HCC among patients with chronic HBV and/or HCV.

METHODS

A prospective cohort of 23,820 residents of Taiwan age 30 to 65 years were enrolled from 1991 to 1992, with 477 instances of HCC occurring subsequently. Serum samples collected at enrollment were tested for seromarkers and viral load of HBV and HCV. Newly developed HCC was ascertained through computerized data linkage with national cancer registry and death certification systems.

RESULTS

The cumulative lifetime (age 30 to 75 years) incidences of HCC for men and women positive for both HBV surface antigen (HBsAg) and antibodies against HCV (anti-HCV) were 38.35% and 27.40%; for those positive for HBsAg only, 27.38% and 7.99%; for those positive for anti-HCV only, 23.73% and 16.71%; and for those positive for neither, 1.55% and 1.03%, respectively. There was a significant male predominance in incidence of HCC for chronic HBV carriers but not for chronic carriers of HCV or both. Multivariate adjusted hazard ratio of developing HCC decreased with age in HBsAg-seropositive men but increased with age in anti-HCV-seropositive women. Among dual-infected participants, there was an inverse association between HBV and HCV viral load. Risk of HCC increased significantly with increasing viral load of HBV and HCV.

CONCLUSION

There exists a suppressive effect of HCV on HBV viral load. Individual and combined effects of the two viruses on HCC vary with sex and age.

Cancer and viral infections in immunocompromised individuals

Over the last 30 years, the increasing use of organ and stem cell transplantation and the AIDS epidemic have led to the realization that some, but not all, human cancers occur more frequently in immunosuppressed individuals. With the notable exception of non-melanoma skin cancer (NMSC), most tumors that show strongly increased incidence rates in both transplant recipients and AIDS patients have been found to have a viral etiology. Among these are Kaposi sarcoma, diffuse large cell B-cell lymphoma, cervical cancer, liver cancer, Merkel cell carcinoma and a subset of Hodgkin's disease. A viral etiology for NMSC, i.e., beta- and gamma-subtypes of human papillomavirus, has been suggested and investigated for many years, but remains controversial. In addition, the moderately increased incidence rates of several other cancers in immunosuppressed individuals (e.g., Vajdic and van Leeuwen, Int J Cancer, in press) could indicate that additional infectious causes for at least some human cancers remain to be discovered. The controversy surrounding the role of cutaneous papillomavirus subtypes in the pathogenesis of NMSC illustrates the difficulties encountered when weighing the epidemiological and molecular biology evidence arguing for an involvement of highly prevalent viruses in certain types of cancer.

Usefulness of technetium-99m tetrofosmin liver imaging to detect hepatocellular carcinoma and related to expression of P-glycoprotein or multidrug resistance associated protein-a preliminary report

Technetium-99m Tetrofsomin (Tc-TF) has been shown to be useful in identifying several types of tumors, such as breast, lung, and thyroid cancers. There was no report in the literature for Tc-TF uptake in hepatocellular carcinoma (HCC). The aim of this study was to evaluate the usefulness of Tc-TF liver imaging to detect HCC and investigate the relationship between Tc-TF liver imaging findings and P-glycoprotein (Pgp) and multidrug resistance associated protein (MRP) expression. Before any therapy, 22 patients with HCC were enrolled in this study. Tc-TF liver images were performed l0 minutes after intravenous injection of 20mCi Tc-TF. All patients had liver biopsy or surgery within l week after Tc-TF liver imaging. Immunohistochemical study of the biopsy or resected HCC specimens was performed using anti-human Pgp and MRP antibodies. Twenty of the 22 (90.9%) patients showed negative Tc-TF liver imaging results without significant Tc-TF uptake in HCC, whereas only the remaining 2 (9.1%) patients showed positive Tc-TF liver imaging results with significant Tc-TF uptake in HCC. Positive Pgp expression was observed in 13 of 20 patients with negative Tc-TF liver imaging results, whereas positive MRP expression was observed in 6 of the remaining 7 patients with negative both Tc-TF liver imaging results and Pgp expression. However, negative Pgp expression but positive MRP expression was observed in all of the remaining 2 patients with positive Tc-TF liver imaging results. The correlation between Tc-TF liver imaging findings and Pgp expression was significant and better than between Tc-TF liver imaging findings and MRP expression. Pgp or MRP expression in HCC may induce no significant Tc-TF uptake in HCC resulting in negative Tc-TF liver imaging findings. Therefore, Tc-TF liver imaging is potential to be a non-invasive method to predict Pgp or MRP expression in HCC. However, further studies with a larger series of patients and longer follow-up time are necessary to confirm our findings.

Effect of P-glycoprotein and multidrug resistance associated protein gene expression on Tc-99m MIBI imaging in hepatocellular carcinoma

P-glycoprotein (Pgp) and multidrug resistance-associated protein (MRP) expressions as well as Tc-99m methoxisobutylisonitrile (MIBI) images were assessed in 25 patients hepatocellular carcinoma (HCC). Tc-99m MIBI imaging was performed 10 minutes after intravenous injection of 20 mCi Tc-99m MIBI. Using immunohistochemical staining, 60% of the HCC lesions showed positive for Pgp and 64% showed positive for MRP. In 3 patients with MIBI uptake, immunohistochemical study of tumor tissue showed no Pgp stained cells. Nevertheless, they were all positive for MRP. The result of Tc-99m MIBI imaging is more related to the expression of Pgp than MRP gene. It is possible that other membrane transporters as well as Pgp and MRP are involved in the efflux of Tc-99m MIBI.

An epidemiologic study of hepatocellular carcinoma in Canada

BACKGROUND AND METHODS

To provide information on poorly described Canadian hepatocellular cancer epidemiology, we analyzed incident cases abstracted from the Canadian Cancer Registration Database (1969-1997) and Canadian annual death data (1969-1998). Age, sex, geographic distribution, and secular trends were described. Projection models were developed for the next decade.

RESULTS

Results indicated much higher incidence and mortality rates in males than females, with substantial increases for both with age. Age-standardized incidence rates increased an average of 3.4% per year in males, 1.2% per year in females (1969-1997). Age-standardized mortality rates increased an average of 1.48% in males, but decreased an average of 0.46% per year in females (1969-1998). Join-point analysis of the linear trends in the age-standardized incidence and mortality rates suggested that a new trend started to emerge about 1991. The fitted non-linear multiplicative model predicted the occurrence of 1,565 new cases and 802 deaths in the year 2010. HCC incidence was the highest in British Colombia, followed by Quebec, and the lowest in the Atlantic region.

CONCLUSIONS

Incidence rates of hepatocellular carcinoma have increased substantially, consistent with the reported increase in the prevalence of Hepatitis C Virus (HCV) and Hepatitis B Virus (HBV) infections in recent decades.

Polycyclic aromatic hydrocarbon-DNA adducts in liver tissues of hepatocellular carcinoma patients and controls

HCC is a common cancer and HBV and AFB(1) are well-documented, major risk factors. Epidemiologic studies have documented that cigarette smoking also contributes to the development of HCC. PAHs are ubiquitous environmental pollutants and products of incomplete combustion. They are present in both mainstream and sidestream cigarette smoke. PAHs are metabolically activated by phase I enzymes, including CYP1A1, into electrophilic reactants (diol epoxides), which covalently bind to DNA to form adducts. Diol epoxides are also substrates for phase II detoxifying enzymes, including GSTM and GSTP. To examine the association between PAH-DNA adducts and HCC, adduct levels were determined in liver tissue by relative staining intensity with an immunoperoxidase method using a polyclonal antiserum against BPDE-modified DNA. Subjects were also genotyped for polymorphism in several genes involved in the metabolism of PAH, including GSTM1 and GSTP1. Liver tissue was collected from patients with histologically confirmed HCC (n = 105) and from non-HCC controls (n = 37). There was a significant positive correlation (r = 0.3, p < 0.01) between adducts in tumor and adjacent nontumor tissues among HCC cases. The risk of HCC was higher after adjustment for age, sex and HBsAg in the group with the highest tertile tissue levels of PAH-DNA adducts (mean relative nuclear staining intensity of tumor and nontumor tissue > 344) than in the group with the lowest tertile (staining < 241, OR = 3.9, 95% CI = 1.0-14.9). Among non-HCC controls, there were no significant associations between adduct levels and cigarette smoking, GSTM1 null genotype and HBsAg positivity. A strikingly increased HCC risk was observed (OR = 20.3, 95% CI = 5.0-81.8) among HBsAg-positive subjects whose PAH-DNA adduct levels were high (mean relative nuclear staining intensity of tumor and nontumor tissue > 301, median of control tissues) compared to HBsAg-negative subjects who had low PAH-DNA adduct levels. 4-ABP- and AFB(1)-DNA adducts had been measured previously in these same tissues. Subjects with elevated DNA adduct levels of PAH, 4-ABP and AFB(1) had a significantly higher HCC risk with an OR of 36.7 (95% CI 7.2-187.2) compared to those who had low DNA adduct levels. These results suggest that PAHs may play a role in human hepatocarcinogenesis in conjunction with HBsAg carrier status, GSTM1 and GSTP1 genotypes and exposure to 4-ABP and AFB(1).

Ultrasound screening and risk factors for death from hepatocellular carcinoma in a high risk group in Taiwan

Although previous studies have demonstrated the ability of ultrasonography (US) screening to detect small asymptomatic hepatocellular carcinoma (HCC), the efficacy of US screening in reducing deaths from HCC still remained unresolved. A 2-stage screening program was designed to identify a high risk group in 7 townships in Taiwan by 6 markers (of risk for HCC) and repeated US screening was further applied to those with at least 1 positive result for the 6 markers, with a range of 3- to 6-month inter-screening intervals to those with liver cirrhosis or other chronic liver diseases and an annual screening regime for the remaining subjects with normal findings according to US. The 4,843 subjects in this cohort were followed up for an average of 7 years. We compared 4,385 attenders with 458 non-attenders, in conjunction with baseline assessment for self-selection bias. In addition, we assessed baseline variables with respect to their effects on risk of incidence of and mortality from HCC and on risk of incidence of liver cirrhosis. The difference in mortality between attenders and non-attenders was then re-estimated adjusting for significant predictors of cirrhosis, HCC incidence and HCC death as a further guard against baseline differences between attenders and non-attenders in risk profiles. Results of US screening for this high risk group found the mortality was lower by 24% (95% CI: -52 to 62%) in the attenders compared to the non-attenders. After adjustment for sensitivity, the mean sojourn time (MST) were 1.57 (95% CI: 0.94-4.68) for subjects with liver cirrhosis and 2.66 (95% CI: 1.68-6.37) years for non-cirrhotic patient. Significant increases in risk of HCC incidence were associated with increasing age, male gender, hepatitis B surface antigen positive (HbsAg), hepatitis C antibody positive (Anti-HCV), high levels of alanine transaminase (ALT) and alpha-fetoprotein (AFP) and a family history of HCC. Significantly increased risks of liver cirrhosis were associated with predictors of cirrhosis were increasing age, HbsAg, high levels of ALT and of AFP. Significant or borderline significant increases in risk of HCC death were associated with increasing age, male gender, HbsAg, high levels of AST and AFP. Adjusted for the significant variables, the mortality was lower by 41% (95% CI: -20 to 71%, p = 0.1446) in the attenders compared to the non-attenders. The present study provides suggestive evidence on the efficacy of US screening in a selective high risk group in an endemic area of hepatitis B. A randomized controlled trial would yield definitive evidence. Within the protocol of such a trial, a shorter interscreening interval for patients with liver cirrhosis is suggested.

Cancer epidemiology and control in Taiwan: a brief review

Malignant neoplasm has become the leading cause of death in Taiwan since 1982. There has been a decreasing trend for cancers of the stomach and cervix uteri, while an increasing trend has been observed for cancers of the lung, liver, oral cavity, colon and rectum, breast and prostate. International comparison and migrant studies have shown an elevated risk of hepatocellular carcinoma, nasopharyngeal carcinoma and cervical neoplasia in Taiwan. The national hepatitis B vaccination program, started in July 1984, has resulted in a significant decrease in childhood hepatocellular carcinoma in Taiwan. A decrease in prevalence of cigarette smoking has been observed among middle-aged men since the control of tobacco hazards was enacted in 1997. Free mass screening of cervical neoplasia and colorectal cancer has been implemented in the national health insurance program since 1995. Project-based screening for hepatocellular carcinoma, nasopharyngeal carcinoma and breast cancer among high-risk groups was started in 1994. Most cancer patients are diagnosed by pathological examinations and treated by surgical operation, chemotherapy and radiotherapy in major teaching hospitals in Taiwan. The Taiwan Collaborative Oncology Group has been organized to assess the efficacy of various treatment modalities through multicentric clinical trials. There has been a striking increase in expenditure for medical care of cancer patients. Cancer researchers mainly sponsored by the National Science Council and Department of Health are engaged in basic, epidemiological and clinical studies on major cancers in Taiwan. Major fields of the research include cancer genomics, gene therapy, molecular epidemiology and DNA vaccine.

The role of diabetes in hepatocellular carcinoma: a case-control study among United States Veterans

OBJECTIVE

Diabetes mellitus (DM) has been reported to increase the risk of hepatocellular carcinoma (HCC). We carried out a case-control study to examine the role of DM while controlling for several known risk factors of HCC.

METHODS

All hospitalized patients with primary liver cancer (PLC) during 1997-1999 were identified in the computerized database of the Department of Veterans Affairs, the Patient Treatment File. Controls without cancer were randomly assigned from the Patient Treatment File during the same time period. The inpatient and outpatient files were searched for several conditions including DM, hepatitis C virus (HCV), hepatitis B virus (HBV), alcoholic cirrhosis, autoimmune hepatitis, hemochromatosis, and nonspecific cirrhosis. Adjusted odds ratios (OR) were calculated in a multivariable logistic regression model.

RESULTS

We identified 823 patients with PLC and 3459 controls. The case group was older (62 yr [+/-10] vs 60 [+/-11], p < 0.0001), had more men (99% vs 97%, 0.0004), and a greater frequency of nonwhites (66% vs 71%, 0.0009) compared with controls. However, HCV- and HBV-infected patients were younger among cases than controls. Risk factors that were significantly more frequent among PLC cases included HCV (34% vs 5%, p < 0.0001), HBV (11% vs 2%, p < 0.0001), alcoholic cirrhosis (47% vs 6%, p < 0.0001), hemochromatosis (2% vs 0.3%, p < 0.0001), autoimmune hepatitis (5% vs 0.5%, p < 0.0001), and diabetes (33% vs 30%, p = 0.059). In the multivariable logistic regression, diabetes was associated with a significant increase in the adjusted OR of PLC (1.57, 1.08-2.28, p = 0.02) in the presence of HCV, HBV, or alcoholic cirrhosis. Without markers of chronic liver disease, the adjusted OR for diabetes and PLC was not significantly increased (1.08, 0.86-1.18, p = 0.4). There was an increase in the HCV adjusted OR (17.27, 95% Cl = 11.98-24.89) and HBV (9.22, 95% CI = 4.52-18.80) after adjusting for the younger age of HCV- and HBV-infected cases. The combined presence of HCV and alcoholic cirrhosis further increases the risk with an adjusted OR of 79.21 (60.29-103.41). The population attributable fraction for HCV among hospitalized veterans was 44.8%, whereas that of alcoholic cirrhosis was 51%.

CONCLUSION

DM increased the risk of PLC only in the presence of other risk factors such as hepatitis C or B or alcoholic cirrhosis. Hepatitis C infection and alcoholic cirrhosis account for most of PLC among veterans.

Prospective study on the relation of cigarette smoking with cancer of the liver and stomach in an endemic region

BACKGROUND

Smoking has not been confirmed as a risk factor for cancers of the liver and stomach. The authors examined prospectively the relationship between smoking and these cancers in an endemic region.

METHODS

The data used were a cohort study on the relationship between lifestyle and health in the region having the highest liver cancer mortality in Japan. Of the cohort members, 4050 males aged > or =40 years were included in the present analysis with a 9-year mean follow-up. Cox proportional hazards regression was used to estimate relative risks (RR) for cancer of the liver, stomach, smoking-related sites and others, while adjusting for age, residence, and alcohol intake.

RESULTS

By the end of the study period, 59 cases of liver cancer and 53 cases of stomach cancer were identified. Current smokers, compared to subjects who had never smoked, had a threefold risk of liver cancer (RR = 3.3; 95% CI: 1.2-9.5) and a twofold risk of stomach cancer (RR = 2.2; 95% CI: 0.8-5.7). Sub-cohort analysis showed that adjustment for history of chronic liver disease did not attenuate the risk of liver cancer. Light/medium smokers had almost the same risk of these cancers as heavy smokers, while they showed a relatively low risk of smoke-related cancers.

CONCLUSIONS

The present results indicate that smoking is a risk factor of liver and stomach cancer in a population with a high background risk for these cancers. However, causal inferences should be made cautiously due to a lack of information on known risk factors.

Consumption of alcohol in the presence of hepatitis C virus is an additive risk for liver damage

BACKGROUND

Whether alcohol consumption influences the development of hepatitis C in the presence of a latent infection needs to be determined.

METHODS

The interaction between alcohol intake and hepatitis C virus infection with regard to development of liver injury was cross-sectionally investigated for 399 inhabitants of a town in Nagano Prefecture, Japan. In this town, the prevalence of hepatitis C virus infection is 32.4%.

RESULTS

The levels of indicators of liver function were significantly higher among subjects of both sexes who carried the antibody to hepatitis C virus than among those without the antibody. Among men, higher levels of liver function were more frequent among alcohol drinkers than among nondrinkers, suggesting that alcohol consumption may aid in the development of liver injury, even among subjects with a latent hepatitis C virus infection. gamma-Glutamyl transpeptidase activity was more sharply increased in relation to alcohol intake among subjects with hepatitis C virus infection than among those without it, suggesting that the presence of infection will influence alcohol-induced liver damage.

CONCLUSION

Alcohol consumption and a concomitant hepatitis C virus infection apparently facilitate the development of hepatitis.

Hepatitis C

Hepatitis C virus (HCV) infection afflicts millions of people in the United States and worldwide. We examine the epidemiology of HCV infection, the molecular biology of the virus, the pathophysiology of infection, the clinical diagnosis and manifestations of infection, and the treatment of HCV infection.

A meta-analysis of epidemiological studies on the combined effect of hepatitis B and C virus infections in causing hepatocellular carcinoma

The aim of the study was to assess whether co-infection by hepatitis-B virus (HBV) and hepatitis-C virus (HCV) is associated with a higher risk of developing hepatocellular carcinoma (HCC) than each infection alone. A meta-analysis of data published up to June 1997 was performed. HBsAg and anti-HCV antibodies or HCV RNA (anti-HCV/HCV RNA) were considered as serological markers of current HBV and HCV infection respectively. A total of 32 case-control studies were suitable for a quantitative overview. The summary odds ratios (OR) were 13.7 for HBsAg positivity and 11.5 for anti-HCV/HCV RNA positivity. The OR for anti-HCV was lower among studies using second- or third-generation anti-HCV or HCV RNA (OR, 8.2) with respect to studies with first-generation anti-HCV test (OR, 19.1). When combining data from the studies with second- or third-generation anti-HCV or HCV RNA, the OR for HBsAg positivity and anti-HCV/HCV RNA negativity was 22.5 (95% confidence interval (CI), 19.5-26.0), the OR for anti-HCV/HCV RNA positivity and HBsAg negativity was 17.3 (95% CI, 13.9-21.6), and the OR for both markers positivity was 165 (95% CI: 81.2-374, based on 191 cases and 8 controls exposed). A synergism was found between HBV and HCV infections, the OR for co-infection being greater than the sum and lower than the product of those for each infection alone. The interaction was therefore negative according to the multiplicative model, providing epidemiological evidence both of an independent effect and of interference between the 2 viruses in the carcinogenic process.

Epidemiological characteristics and risk factors of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the major cancers in the world. There is a striking variation in HCC incidence rates between various countries, with a highest-to-lowest ratio of 112.5 for males and 54.7 for females. The high-risk populations are clustered in sub-Saharan Africa and eastern Asia. The male-to-female ratio for HCC ranges from < 1 to 6.4 and mostly from 2 to 4. There exist significant variations in the incidence of HCC among different ethnic groups living in the same area and among migrants of the same ethnic groups living in different areas. The age curves of HCC are significantly different in various countries, suggesting variability in exposure to risk factors. Chronic carriers of hepatitis B and C viruses (HBV and HCV, respectively) have an increased risk of HCC. The relative and attributable HCC risk of HBV and HCV carrier status varies in different countries. There exists a synergistic interaction on HCC between the two viruses. Aflatoxin exposure, cigarette smoking, heavy alcohol consumption, low vegetable intake, inorganic arsenic ingestion, radioactive thorium dioxide exposure, iron overload and the use of oral contraceptives and anabolic steroids have been documented as HCC risk factors. Recent molecular epidemiological studies have shown that low serum retinol levels as well as elevated serum levels of testosterone, neu oncoprotein and aflatoxin B1-albumin adduct are associated with an increased HCC risk. There is a synergistic interaction on HCC between chronic HBV infection and aflatoxin exposure. Familial aggregation of HCC exists and a major susceptibility gene of HCC has been hypothesized. Patients of some genetic diseases are at an increased risk of HCC. The genetic polymorphisms of cytochrome P450 2E1 and 2D6 and arylamine N-acetyltransferase 2 are associated with the development of HCC. A dose-response relationship between aflatoxin exposure and HCC has been observed among chronic HBV carriers who have null genotypes of glutathione S-transferase M1 or T1, but not among those who have non-null genotypes. Human hepatocarcinogenesis is a multistage process with the involvement of a multifactorial aetiology. Gene-environment interactions are involved in the development of HCC in humans.

Seroprevalences of hepatitis B and C viruses and Helicobacter pylori infection in a small, isolated population at high risk of gastric and liver cancer

The objective of this study was to examine the seroprevalences of chronic infection with hepatitis B and C viruses and Helicobacter pylori in Matzu, a group of small islets with 5,566 civilian residents who have extremely high mortality from cancers of the stomach and liver. The standardized mortality ratios (SMR) of all cancer sites combined, liver cancer and stomach cancer in 1984-1993 were calculated using the general population in Taiwan as the referent (SMR = 100). The SMRs (95% confidence interval) for all cancer sites combined, liver cancer and stomach cancer were 160 (131-195), 252 (170-360) and 351 (229-516), respectively, in Matzu. A health survey was carried out with 1,485 civilian residents aged 30 years or more, giving a response rate of 69% among those who were eligible. Serum samples were tested for antibodies against Helicobacter pylori (anti-HP) by enzyme-linked immunosorbent assay and hepatitis B surface antigen (HBsAg) and antibodies against hepatitis C virus (anti-HCV) by enzyme immunoassay. The seroprevalence was 61% for anti-HP, 24.7% for HBsAg and 1.8% for anti-HCV in Matzu. While mortality rates of liver and stomach cancers were significantly higher in Matzu than in Taiwan, the seroprevalences of anti-HP, HBsAg and anti-HCV in Matzu were similar to or even lower than those in Taiwan. These findings suggest the existence of risk factors other than microbial agents involved in the development of stomach and liver cancers.

Low prevalence of hepatitis C infection in hepatocellular carcinoma (HCC) cases and population controls in Guangxi, a hyperendemic region for HCC in the People's Republic of China

Southern Guangxi, China has one of the highest incidences of hepatocellular carcinoma (HCC) in the world. Serum samples collected from subjects of an earlier case-control study (39 cases, 41 controls) and from a random sampling of a residential male cohort (n = 100) were tested for antibodies for the hepatitis C virus (anti-HCV) using ELISA version 2.0 with confirmation by RIBA version 2.0. Only one of 141 (0.7%, upper 95% confidence limit, 3.2%) control subjects and none of 39 (upper 95% confidence limit, 6.07%) HCC cases tested positive for anti-HCV. Our results indicate that hepatitis C infection is not an important environmental determinant of HCC risk in this hyperendemic region.

Hepatitis C virus and organ transplantation

Hepatitis C virus (HCV) is both the leading cause of cirrhosis and hepatic failure leading to liver transplantation and a cause of chronic hepatitis in approximately 10% of all transplant recipients. Beginning 5-10 years or more posttransplant, HCV causes progressive liver disease in a significant fraction of infected individuals and contributes to an increased incidence of opportunistic infection and hepatocellular carcinoma. The existence of multiple genotypes of HCV with differing biologic behaviors and the generation of antigenic diversity of the virus (quasispecies) during the course of infection, limit the capacity of the immune system to generate protective immunity. Antiviral therapy with interferon-alpha is effective in only a minority of transplant patients, and since allografts from HCV infected donors are quite efficient in transmitting the virus, great attention is paid to the appropriate use of organs from HCV-positive donors. At present, these organs should be particularly targeted for patients in emergent need of lifesaving heart, liver, or lung transplants. Issues requiring further investigation include the impact of viral superinfection on HCV-infected recipients of organs from HCV-infected donors and the use of such organs in seronegative patients who are older, diabetic, or highly sensitized, for whom quality of life issues may outweigh the long-term impact of HCV infection.

Cytochrome P450 2E1 and glutathione S-transferase M1 polymorphisms and susceptibility to hepatocellular carcinoma

BACKGROUND & AIMS

Genetic polymorphisms in enzymes involved in carcinogen metabolism have been found to influence susceptibility to cancer. The aim of this study was to examine whether cytochrome P450 2E1 (CYP2E1) and/or glutathione S-transferase M1 (GSTM1) genetic polymorphisms were related to susceptibility to hepatocellular carcinoma (HCC).

METHODS

Genotyping of CYP2E1 and GSTM1 was performed using the polymerase chain reaction on peripheral white blood cell DNA from 30 patients with HCC and 150 controls nested in a cohort study.

RESULTS

The c1/c1 genotype of CYP2E1, detected by PstI or RsaI digestion, was found in 83.3% of patients with HCC and in 63.3% of controls (P = 0.034). Homozygosity for the c1/c1 genotype significantly increased the risk of developing HCC in cigarette smokers (P = 0.001) but posed no increased risk in those who never smoked. The HCC risk associated with cumulative exposure to cigarette smoke was also more striking in individuals who carried the c1/c1 genotype. Habitual alcohol drinking modified the HCC risk of cigarette smoking among those with the c1/c1 genotype. No association with the risk of HCC was observed for the DraI polymorphism of CYP2E1 or for the GSTM1-null genotype.

CONCLUSIONS

Polymorphisms of CYP2E1 may play an important role in cigarette smoking-related hepatocarcinogenesis.