Risk factors for hepatocellular carcinoma among Japanese women

Effects of Curcumin on Tobacco Smoke-induced Hepatic MAPK Pathway Activation and Epithelial-Mesenchymal Transition In Vivo

Tobacco smoke is a major risk factor for hepatic cancer. Epithelial-mesenchymal transition (EMT) induced by tobacco smoke is crucially involved in the initiation and development of cancer. Mitogen-activated protein kinase (MAPK) pathways play important roles in tobacco smoke-associated carcinogenesis including EMT process. The chemopreventive effect of curcumin supplementation against cancers has been reported. In this study, we investigated the effects of tobacco smoke on MAPK pathway activation and EMT alterations, and then the preventive effect of curcumin was examined in the liver of BALB/c mice. Our results indicated that exposure of mice to tobacco smoke for 12 weeks led to activation of ERK1/2, JNK, p38 and ERK5 pathways as well as activator protein-1 (AP-1) proteins in liver tissue. Exposure of mice to tobacco smoke reduced the hepatic mRNA and protein expression of the epithelial markers, while the hepatic mRNA and protein levels of the mesenchymal markers were increased. Treatment of curcumin effectively attenuated tobacco smoke-induced activation of ERK1/2 and JNK MAPK pathways, AP-1 proteins and EMT alterations in the mice liver. Our data suggested the protective effect of curcumin in tobacco smoke-triggered MAPK pathway activation and EMT in the liver of BALB/c mice, thus providing new insights into the chemoprevention of tobacco smoke-associated hepatic cancer. Copyright © 2017 John Wiley & Sons, Ltd.

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.

MicroRNA response to environmental mutagens in liver

During the recent few years, microRNAs emerged as key molecules in the regulation of mammalian cell functions. It was also shown that their altered expression can promote pathologic conditions, such as cancer and other common diseases. Because environmental exposure to biological, chemical or physical agents may be responsible for human diseases, including cancer, uncovering relationships between exposure to environmental carcinogens and expression of microRNAs may help to disclose early mechanisms of disease and it may potentially lead to the development of useful indicators of toxic exposure or novel biomarkers for carcinogenicity testing. The unique expression profile of microRNAs in different types and at different stages of cancer coupled to their remarkable stability in tissues and in serum/plasma suggests that these little molecules may find application as sensitive biomarkers. This review will concentrate on the alterations in microRNA expression in response to environmental factors in relation to the risk of developing liver cancer.

Meta-analysis of epidemiologic studies on cigarette smoking and liver cancer

BACKGROUND

Whereas the International Agency for Research on Cancer (IARC) Monograph concluded that the evidence for the relationship between cigarette smoking and liver cancer is sufficient, the US Surgeon General's report summarized the data as suggestive but not sufficient.

METHODS

A meta-analysis of previous epidemiologic studies may help to clarify the potential association. We identified 38 cohort studies and 58 case-control studies in a systematic literature search for studies on liver cancer and cigarette smoking. The meta-relative risk (mRR) of liver cancer and dose-response trends were calculated. Tests for heterogeneity, publication bias assessment and influence analyses were performed.

RESULTS

Compared with never smokers, the adjusted mRR was 1.51 [95% confidence interval (CI) 1.37-1.67] for current smokers and 1.12 (95% CI 0.78-1.60) for former smokers. The increased liver cancer risk among current smokers appeared to be consistent in strata of different regions, study designs, study sample sizes and publication periods.

CONCLUSION

The results of our meta-analysis show that tobacco smoking is associated with liver cancer development, which supports the conclusion by the IARC Monograph. This conclusion has an important public health message for areas with high smoking prevalence and high liver cancer incidence such as China.

Effect of different types of smoking and synergism with hepatitis C virus on risk of hepatocellular carcinoma in American men and women: case-control study

The International Agency for Research on Cancer has declared smoking to be a risk factor for hepatocellular carcinoma (HCC). However, passive exposure to cigarette smoke and use of noncigarette tobacco products on the risk of HCC has not been examined. Therefore, we evaluated the independent effects of different types of smoking exposure along with multiple risk factors for HCC and determined whether the magnitude of smoking was modified by other risk factors in men and women. We conducted a case-control study at The University of Texas M. D. Anderson Cancer Center where 319 HCC patients and 1,061 healthy control subjects were personally interviewed for several HCC risk factors. Multivariate logistic regression analysis was performed to estimate the adjusted odds ratio (AOR) and 95% confidence interval (CI) for each potential risk factor. Use of smokeless tobacco (chewing tobacco and snuff), cigars, pipes and passive smoking exposure were not related to HCC among noncigarette smokers. However, regular cigarette smoking was associated with HCC in men: AOR, 1.9 (95% CI, 1.1-3.1). Heavy alcohol consumption was associated with HCC in women: AOR, 7.7 (95% CI, 2.3-25.1). Cigarette smoking interacted synergistically with chronic infection of hepatitis C virus in men: AOR, 136.3 (95% CI, 43.2-429.6) and with heavy alcohol consumption in women: AOR, 13.7 (95% CI, 3.2-57.9). We conclude that sex differences were observed in HCC relationship with cigarette smoking and alcohol consumption. Controlling for smoking exposure might be a prudent approach to the prevention of HCC, especially in patients with chronic viral hepatitis infections.

Case-control study on cigarette smoking and the risk of hepatocellular carcinoma among Japanese

Emerging epidemiologic data suggest that cigarette smoking may increase the risk of hepatocellular carcinoma (HCC), yet considerable controversies (e.g. inconsistent dose-response relationships) still exist with this association. We examined whether smoking was associated with HCC risk in a case-control study including 209 incident HCC cases and two different control groups (256 hospital controls and 381 patients with chronic liver disease [CLD] without HCC). Comparison of HCC cases with CLD patients, but not with hospital controls, demonstrated a significantly increased risk of HCC for current smokers. After adjustment for sex, age, heavy drinking history and hepatitis virus markers, odds ratios (and 95% confidence intervals) for former and current smokers relative to never smokers were 1.0 (0.6-1.7) and 2.5 (1.4-4.6), respectively, against CLD patients, as compared with 0.8 (0.3-2.3) and 1.8 (0.6-5.1), respectively, against hospital controls. In terms of pack-years during lifetime, dose-response relationship was not evident against either control group (P trend = 0.43), but it became clearer for more recent cigarette use among CLD patients. For example, regarding cumulative cigarette consumption during the last 5 years, adjusted odds ratios (and 95% confidence intervals) for 1-4 and 5+ pack-years relative to no use were 1.9 (1.1-3.6) and 2.8 (1.5-5.2) (P trend = 0.003), respectively. These results suggest that cigarette smoking may play a crucial role in the late stage of HCC development and that CLD patients may benefit from their earliest smoking cessation.

Solid cancer incidence in atomic bomb survivors: 1958-1998

This is the second general report on radiation effects on the incidence of solid cancers (cancers other than malignancies of the blood or blood-forming organs) among members of the Life Span Study (LSS) cohort of Hiroshima and Nagasaki atomic bomb survivors. The analyses were based on 17,448 first primary cancers (including non-melanoma skin cancer) diagnosed from 1958 through 1998 among 105,427 cohort members with individual dose estimates who were alive and not known to have had cancer prior to 1958. Radiation-associated relative risks and excess rates were considered for all solid cancers as a group, for 19 specific cancer sites or groups of sites, and for five histology groups. Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose response, how these risks vary with gender, age at exposure, and attained age, and the evidence for inter-site variation in the levels and patterns of the excess risk. For all solid cancers as a group, it was estimated that about 850 (about 11%) of the cases among cohort members with colon doses in excess of 0.005 Gy were associated with atomic bomb radiation exposure. The data were consistent with a linear dose response over the 0- to 2-Gy range, while there was some flattening of the dose response at higher doses. Furthermore, there is a statistically significant dose response when analyses were limited to cohort members with doses of 0.15 Gy or less. The excess risks for all solid cancers as a group and many individual sites exhibit significant variation with gender, attained age, and age at exposure. It was estimated that, at age 70 after exposure at age 30, solid cancer rates increase by about 35% per Gy (90% CI 28%; 43%) for men and 58% per Gy (43%; 69%) for women. For all solid cancers as a group, the excess relative risk (ERR per Gy) decreases by about 17% per decade increase in age at exposure (90% CI 7%; 25%) after allowing for attained-age effects, while the ERR decreased in proportion to attained age to the power 1.65 (90% CI 2.1; 1.2) after allowing for age at exposure. Despite the decline in the ERR with attained age, excess absolute rates appeared to increase throughout the study period, providing further evidence that radiation-associated increases in cancer rates persist throughout life regardless of age at exposure. For all solid cancers as a group, women had somewhat higher excess absolute rates than men (F:M ratio 1.4; 90% CI 1.1; 1.8), but this difference disappears when the analysis was restricted to non-gender-specific cancers. Significant radiation-associated increases in risk were seen for most sites, including oral cavity, esophagus, stomach, colon, liver, lung, non-melanoma skin, breast, ovary, bladder, nervous system and thyroid. Although there was no indication of a statistically significant dose response for cancers of the pancreas, prostate and kidney, the excess relative risks for these sites were also consistent with that for all solid cancers as a group. Dose-response estimates for cancers of the rectum, gallbladder and uterus were not statistically significant, and there were suggestions that the risks for these sites may be lower than those for all solid cancers combined. However, there was emerging evidence from the present data that exposure as a child may increase risks of cancer of the body of the uterus. Elevated risks were seen for all of the five broadly classified histological groups considered, including squamous cell carcinoma, adenocarcinoma, other epithelial cancers, sarcomas and other non-epithelial cancers. Although the data were limited, there was a significant radiation-associated increase in the risk of cancer occurring in adolescence and young adulthood. In view of the persisting increase in solid cancer risks, the LSS should continue to provide important new information on radiation exposure and solid cancer risks for at least another 15 to 20 years.

Hepatocellular carcinoma: epidemiology and molecular carcinogenesis

Primary liver cancer, which consists predominantly of hepatocellular carcinoma (HCC), is the fifth most common cancer worldwide and the third most common cause of cancer mortality. HCC has several interesting epidemiologic features including dynamic temporal trends; marked variations among geographic regions, racial and ethnic groups, and between men and women; and the presence of several well-documented environmental potentially preventable risk factors. Moreover, there is a growing understanding on the molecular mechanisms inducing hepatocarcinogenesis, which almost never occurs in healthy liver, but the cancer risk increases sharply in response to chronic liver injury at the cirrhosis stage. A detailed understanding of epidemiologic factors and molecular mechanisms associated with HCC ultimately could improve our current concepts for screening and treatment of this disease.

Cigarette smoking and primary liver cancer: a population-based case-control study in US men

OBJECTIVE

Using the case-control data from the Selected Cancers Study, the authors assessed whether cigarette smoking increases the risk of primary liver cancer in the US.

METHODS

Cases were men who were pathologically diagnosed with primary liver cancer during 1984-1988, were 31-59 years old, and lived in the areas covered by eight US cancer registries (n=168). Controls were men without a history of primary liver cancer who were selected by random-digit telephone dialing (n=1910).

RESULTS

Relative to non-smokers, the risks of liver cancer were 1.85 (95% confidence interval (CI), 1.05-3.25) and 1.49 (95% CI, 0.83-2.68) for former and current smokers, respectively. The adjusted odds ratio (OR) estimates were 0.96, 1.43, 1.80, and 1.87 for smoking for less than 15, 15-24, 25-34 and 35 or more years, respectively (p for trend=0.039). The OR estimates were 1.41 (95% CI, 0.74-2.68), 1.67 (95% CI, 0.93-2.98), and 1.83 (95% CI, 0.89-3.76) for less than 1, 1-2, and 2 or more packs smoked per day (p for trend=0.068).

CONCLUSIONS

Cigarette smoking may be a factor that contributes somewhat to the occurrence of primary liver cancer among men in the United States, a country with low risk of liver cancer.

hOGG1 Ser326Cys polymorphism and risk of hepatocellular carcinoma among Japanese

BACKGROUND

The Ser326Cys polymorphism in human oxoguanine glycosylase 1 (hOGG1), which is involved in the repair of 8-hydroxy-2-deoxyguanine in oxidatively damaged DNA, has been associated with susceptibility to certain cancers, but has not been examined in causation of hepatocellular carcinoma (HCC).

METHODS

We conducted a case-control study to investigate whether this polymorphism was related to HCC risk with any interaction with alcohol consumption and cigarette smoking. Genotyping was performed by a polymerase chain reaction with confronting two-pair primers among 209 newly diagnosed HCC cases, 275 hospital controls, and 381 patients with chronic liver disease (CLD) without HCC.

RESULTS

Overall, the hOGG1 genotype was not significantly associated with HCC; adjusted odds ratios (and 95% confidence intervals) for the Ser/Cys and Cys/Cys genotypes compared with the Ser/Ser genotype were 0.79 (0.35-1.79) and 0.48 (0.18-1.27) against hospital controls, and 1.51 (0.96-3.37) and 0.86 (0.50-1.47) against CLD patients. We could not detect any significant gene-alcohol interaction (p = 0.95 or 0.16) or gene-smoking interaction (p = 0.70 or 0.69).

CONCLUTIONS

These results suggest that the hOGG1 Ser326Cys polymorphism may not play a major role as an independent factor in hepatocarcinogenesis.

A prospective study of blood transfusion history and liver cancer in a high-endemic area of Japan

BACKGROUND

The high prevalence of liver cancer in Japan may be owing to infection with hepatitis C virus (HCV), for which the major transmission route is blood transfusion. However, among the general population, there have been few follow-up studies of people with a history of transfusion. The purpose of this study was to examine whether such a history correlates with the development of liver cancer among the general population of this high-endemic area.

STUDY DESIGN AND METHODS

The baseline survey was conducted between 1986 and 1991 among the population (15,597 people, aged 30-79) of Fukuoka prefecture, Japan. The participants were assessed for their transfusion history and other covariates using a baseline questionnaire. The relative risk (RR) of blood transfusion for liver cancer was estimated using the Cox proportional hazard model.

RESULTS

The RRs of transfusion for subsequent liver cancer were 1.86 (95% confidence interval (CI) = 1.05-3.29) in men and 4.20 (95% CI = 1.83-9.61) in women, after adjusting for covariates. Transfusion was associated with an increased risk of liver cancer, mainly in the group without hepatitis and cirrhosis (RR = 1.81, 95% CI = 0.84-3.91 - men; RR = 4.39, 95% CI = 1.37-14.02 - women).

CONCLUSION

A history of blood transfusion carried a significant risk of developing liver cancer in the study region. The people with a history of transfusion should be monitored more aggressively for viral infections and liver disease, as they may not report the infection or they may be unaware that they are infected.

Tobacco use and cancer causation: association by tumour type

In the second part of our review we describe the association between tobacco use and risk of specific cancer types. There is evidence for an established association of tobacco use with cancer of the lung and larynx, head and neck, bladder, oesophagus, pancreas, stomach and kidney. In contrast, endometrial cancer is less common in women who smoke cigarettes. There are some data suggesting that tobacco use increases the risk for myeloid leukaemia, squamous cell sinonasal cancer, liver cancer, cervical cancer, colorectal cancer after an extended latency, childhood cancers and cancer of the gall bladder, adrenal gland and small intestine. Other forms of cancer, including breast, ovarian and prostate cancer, are unlikely to be linked to tobacco use.

Risk factors for focal nodular hyperplasia of the liver: an Italian case-control study

OBJECTIVES

Risk factors for focal nodular hyperplasia (FNH) of the liver are largely unknown, except for a possible role of female hormones. We evaluated the role of tobacco smoking and some lifestyle and dietary factors in its etiology.

METHODS

A hospital-based case-control study was conducted in Italy between January, 1999 and February, 2000 on 28 patients with histologically confirmed FNH of the liver and 115 controls in the hospital for acute, nonneoplastic, non-liver related diseases. Odds ratios (OR) and 95% confidence intervals (CI) were computed using multiple logistic regression equations.

RESULTS

Compared to those who never smoked the multivariate ORs were 1.9 (95% CI = 0.6-6.0) in ex-smokers and 3.5 (95% CI = 1.2-9.7) in current smokers, and the risk increased with number of cigarettes smoked to 8.0 (95% CI = 1.7-37.4) for > or = 20 cigarettes/day. Intake of whole-grain foods was inversely related to risk, with an OR of 0.3 (95% CI = 0.1-0.7) in consumers versus nonconsumers. No significant association was observed with education, alcohol drinking, and selected indicator foods.

CONCLUSIONS

This study indicates that cigarette smoking is an indicator of elevated risk for FNH of the liver, whereas whole grain and, possibly, vegetable intake seems to be a favorable indicator.

Relationship between alcohol drinking, ADH2 and ALDH2 genotypes, and risk for hepatocellular carcinoma in Japanese

The polymorphism in the ALDH2 gene plays a central role in Asian alcohol hypersensitivity and has been associated with the risk for esophageal cancer. In the present study, we attempted to examine associations between the ADH2 and ALDH2 polymorphisms, alcohol drinking and hepatocellular carcinoma (HCC) development in a case-control study in Japan. One hundred and two patients with HCC (85 males and 17 females) and 125 control subjects (101 males and 24 females) were enrolled in the study. Higher cumulative amounts of alcohol consumption (drink-years of > or = 40 drinks/day x year) showed a significant association with HCC development (odds ratio, OR = 2.7; 95% CI = 1.3-5.5, adjusted for age and smoking). By contrast, we could find no association of the ALDH2 genotypes with HCC development (adjusted OR for ALDH2*1/*2 = 1.1; 95% CI = 0.6-2.1). Likewise, the ADH2 genotypes were not associated with HCC development (adjusted OR for ADH2*2/*2 = 0.8; 95% CI = 0.5-1.5). The present results do not support a contribution of acetaldehyde, an active metabolite of ethanol, to HCC development and rather indicate a direct involvement of ethanol in hepatocarcinogenesis.

Attributable risks for hepatocellular carcinoma in northern Italy

The population attributable risks (ARs) for hepatocellular carcinoma (HCC) were estimated in relation to low education level, heavy alcohol consumption, low vegetable and fruit intake, history of hepatitis, diabetes, liver cirrhosis and oral contraceptive use, using data from a case-control study conducted between 1984 and 1993 in Northern Italy. Cases were 320 patients (235 males and 85 females) with histologically or serologically confirmed HCC, and controls were 1408 patients (1031 males and 377 females) admitted to the same network of hospitals for acute, non-neoplastic or non-digestive tract conditions, unrelated to any of the known or likely risk factors for primary liver cancer. The ARs were 40% for low vegetable and fruit consumption, 31% for low education, 18% for liver cirrhosis, 16% for hepatitis, 8% for diabetes and 7% for heavy alcohol consumption. Together, these factors explained 74% of hepatocellular cancer cases. Compared with females, males had higher ARs for cirrhosis (21% versus 11%), diabetes (10% versus 2%) and heavy alcohol consumption (9% versus 1%). The percentage of HCC attributable to all factors considered together was 78% for males and 67% for females. Thus, even if available information on hepatitis and dietary factors was limited, and the AR estimates were based on several arbitrary assumptions, available knowledge could, in principle, reduce the burden of the disease in Italy from 3300 deaths to approximately 750 for males, and from 1600 to approximately 500 for females.