Population attributable risk of aflatoxin-related liver cancer: systematic review and meta-analysis

The intestinal barrier as an emerging target in the toxicological assessment of mycotoxins

Mycotoxins, the secondary metabolites of fungal species, are the most frequently occurring natural food contaminants in human and animal diets. Risk assessment of mycotoxins focused as yet on their mutagenic, genotoxic and potential carcinogenic effects. Recently, there is an increasing awareness of the adverse effects of various mycotoxins on vulnerable structures in the intestines. In particular, an impairment of the barrier function of the epithelial lining cells and the sealing tight junction proteins has been noted, as this could result in an increased translocation of luminal antigens and pathogens and an excessive activation of the immune system. The current review aims to provide a summary of the available evidence regarding direct effects of various mycotoxins on the intestinal epithelial barrier. Available data, based on different cellular and animal studies, show that food-associated exposure to certain mycotoxins, especially trichothecenes and patulin, affects the intestinal barrier integrity and can result in an increased translocation of harmful stressors. It is therefore hypothesized that human exposure to certain mycotoxins, particularly deoxynivalenol, as the major trichothecene, may play an important role in etiology of various chronic intestinal inflammatory diseases, such as inflammatory bowel disease, and in the prevalence of food allergies, particularly in children.

Global Cancer in Women: Burden and Trends

This review is an abbreviated version of a report prepared for the American Cancer Society Global Health department and EMD Serono, Inc., a subsidiary of Merck KGaA, Darmstadt, Germany, which was released at the Union for International Cancer Control World Cancer Congress in Paris in November 2016. The original report can be found at https://www.cancer.org/health-care-professionals/our-global-health-work/global-cancer-burden/global-burden-of-cancer-in-women.html. Staff in the Intramural Research Department of the American Cancer Society designed and conducted the study, including analysis, interpretation, and presentation of the review. The funding sources had no involvement in the study design, data analysis and interpretation, or preparation of the reviewThere are striking disparities in the global cancer burden in women, yet few publications highlight cancer occurrence in this population, particularly for cancers that are not sex specific. This article, the first in a series of two, summarizes the current burden, trends, risk factors, prevention, early detection, and survivorship of all cancers combined and seven sites (breast, cervix, uterine corpus, ovary, colorectum, lung, and liver) that account for about 60% of the cancer burden among women worldwide, using data from the International Agency for Research on Cancer. Estimated 2012 overall cancer death rates in general are higher among women in low- and middle-income countries (LMICs) than high-income countries (HICs), despite their lower overall incidence rates, largely due to inadequate access to early detection and treatment. For example, the top mortality rates are in Zimbabwe (147 deaths per 100,000) and Malawi (138). Furthermore, incidence rates of cancers associated with economic development (e.g., lung, breast, colorectum) are rising in several LMICs. The burden of cancer among women could be substantially reduced in both HICs and LMICs through broad and equitable implementation of effective interventions, including tobacco control, HPV and HBV vaccination, and screening (breast, cervix, and colorectum). Cancer Epidemiol Biomarkers Prev; 26(4); 444-57. ©2017 AACRSee related article by Islami et al. in this CEBP Focus section, "Global Cancer in Women."

Non‑infective occupational risk factors for hepatocellular carcinoma: A review (Review)

Liver cancer is the second leading worldwide cause of cancer‑associated mortalities. Hepatocellular carcinoma, which accounts for the majority of liver tumors, ranks fifth among types of human cancer. Well‑established risk factors for liver cancer include the hepatitis B and C viruses, aflatoxins, alcohol consumption, and oral contraceptives. Tobacco smoking, androgenic steroids, and diabetes mellitus are suspected risk factors. Current knowledge regarding non‑infective occupational risk factors for liver cancer is inconclusive. The relevance of liver disorders to occupational medicine lies in the fact that the majority of chemicals are metabolized in the liver, and toxic metabolites generated via metabolism are the predominant cause of liver damage. However, their non‑specific clinical manifestations that are similar in a number of liver diseases make diagnosis difficult. Furthermore, concomitant conditions, such as viral hepatitis and alcohol or drug abuse, may mask liver disorders that result from occupational hepatotoxic agents and block the demonstration of an occupational cause. The identification of environmental agents that result in human cancer is a long and often difficult process. The purpose of the present review is to summarize current knowledge regarding the association of non‑infective occupational risk exposure and HCC, to encourage further research and draw attention to this global occupational public health problem.

High enrichment and ultra-trace analysis of aflatoxins in edible oils by a modified hollow-fiber liquid-phase microextraction technique

An improved hollow-fiber liquid-phase microextraction approach with excellent purification and enrichment capabilities enabled the method have good potential for future ultra-trace analysis of AFTs.

How climate change and regulations can affect the economics of mycotoxins

In the decades to come, the one factor that will likely have the greatest effect on the economics of the mycotoxin problem is climate change. This article reviews the current state of known science on how the global climate has been changing in recent decades, as well as likely climate change trends in the near future. The article focuses in depth on how climatic variables affect fungal infection and production of specific mycotoxins in food crops, and how near-future climatic changes will shape the prevalence of these mycotoxins in crops in different parts of the world. Because of regulatory limits set on maximum allowable levels of mycotoxins in food and feed, growers will experience economic losses if climatic factors cause certain mycotoxins to become more prevalent. A case study is presented of how maize growers in the United States will experience increased economic losses due to slightly higher aflatoxin levels in maize, even if those levels may still be below regulatory limits. We discuss the overall expected economic impacts of climate change-induced mycotoxin contamination worldwide – not just market-related losses, but also losses to human and animal health and risks to food security. Aflatoxin is the mycotoxin that is most likely to increase under near-future climate scenarios; and thus is likely to pose the greatest amount of economic risk of all the mycotoxins.

Mycotoxin in the food supply chain-implications for public health program

Mycotoxins are a group of naturally occurring toxic chemical substances, produced mainly by microscopic filamentous fungal species. Regarding potential synergisms or even mitigating effects between toxic elements, mycotoxin contamination will continue to be an area of concern for producers, manufacturers, regulatory agencies, researchers, and consumers in the future. In Serbia, recent drought and then flooding confirmed that mycotoxins are one of the foodborne hazards most susceptible to climate change. In this article, we review key aspects of mycotoxin contamination of the food supply chain and implications for public health from the Serbian perspective.

Comparison of hepatocellular carcinoma in Eastern versus Western populations

Hepatocellular carcinoma (HCC) is a heterogeneous disease that remains highly prevalent in many Asian countries and is the second most common cause of cancer-related mortality worldwide. Significant differences exist between Eastern and Western populations on many key aspects of HCC, contributing to the potential different treatment outcomes and challenges of clinical trial design and data interpretation. In this review, the authors compare HCC in Asia versus the West and highlight 1) differences in terms of epidemiology and trends and their correlation with etiology, 2) differences in genetics and how they relate to underlying etiology, 3) differences in treatment approaches based on existing guidelines and consensus statements, and 4) differences in clinical outcomes for Asian versus non-Asian patients with HCC in clinical trials and the implications for future clinical trial design. Cancer 2016;122:3430-3446. © 2016 American Cancer Society.

Analysis of Risk Factors Associated with the Development of Hepatocellular Carcinoma in Chronic HBV-Infected Chinese: A Meta-Analysis

Hepatitis B virus (HBV) infection is a major risk factor for the development of hepatocellular carcinoma (HCC) in China. At present, there still are 9.3 million chronic HBV-infected Chinese. Numerous studies have explored the association between possible factors and hepatocellular carcinoma risk, however, the results remains inconsistent. Therefore, we did this pooled analysis so as to get a precise result. Here, we took the chronic HBV-infected Chinese as the object. We systematically searched for studies evaluating whether the proposed factors changed HCC risk in PubMed, Chinese National Knowledge Infrastructure, VIP database and Wanfang data. Odds ratios (OR) with 95% confidence intervals (CI) were calculated by Review Manager 5.0 and publication bias was determined by Begg’s test and Egger’s test. In total, 3165 cases and 10,896 controls from 27 studies were included in this meta-analysis. Our results showed that pooled OR with 95% CI for each of the factors investigated were: non-antiviral treatment 2.70 (2.01, 3.62), high HBV DNA levels 2.61 (1.73, 3.94), alcohol consumption 2.19 (1.53, 3.13), a family history of HCC 3.58 (2.53, 5.06) and male gender 2.14 (1.68, 2.73), respectively. Our meta-analysis supports that high HBV DNA levels, non-antiviral treatment, alcohol consumption, a family history of HCC and male gender contributed to the risk of hepatocellular carcinoma in chronic HBV-infected Chinese from currently available evidence. Given the high prevalence of the non-antiviral treatment and alcohol drinking, behavior interventions for the two factors should be tackled first.

Inhibitory Activities of Alkyl Syringates and Related Compounds on Aflatoxin Production

Inhibitors of aflatoxin production of aflatoxigenic fungi are useful for preventing aflatoxin contamination in crops. As methyl syringate weakly inhibits aflatoxin production, aflatoxin production inhibitory activities of additional alkyl syringates with alkyl chains from ethyl to octyl were examined. Inhibitory activity toward aflatoxin production of Aspergillus flavus became stronger as the length of the alkyl chains on the esters became longer. Pentyl, hexyl, heptyl, and octyl syringates showed strong activity at 0.05 mM. Heptyl and octyl parabens, and octyl gallate also inhibited aflatoxin production as strongly as octyl syringate. Alkyl parabens and alkyl gallates inhibit the complex II activity of the mitochondrial respiration chain; thus, whether alkyl syringates inhibit complex II activity was examined. Inhibitory activities of alkyl syringates toward complex II also became stronger as the length of the alkyl chains increased. The complex II inhibitory activity of octyl syringate was comparable to that of octyl paraben and octyl gallate. These results suggest that alkyl syringates, alkyl parabens, and alkyl gallates, including commonly used food additives, are useful for aflatoxin control.

Determination of Environmental Exposure to Microcystin and Aflatoxin as a Risk for Renal Function Based on 5493 Rural People in Southwest China

Although the nephrotoxicity of microcystin and aflatoxin has been observed in animal and clinical cases, few population data are available. We conducted a cross-sectional study in Southwest China to investigate the association of renal function indicators (RFIs, including BUN, SCr, and eGFR) with exposure to microcystin and aflatoxin in 5493 members of the general population. Microcystin-LR levels in water and aquatic products and aflatoxin B1 levels in daily foods were measured by ELISA, and individual estimated daily intake (EDI) was assessed on the basis of the measurement and questionnaire. We found that participants with abnormal RFIs had a much higher mean level of microcystin-LR EDI than those with normal RFIs and that there was a significant increasing trend for abnormal rates and odds ratios of RFIs with increasing microcystin-LR EDI quartiles (p for trend = 0.000). Compared with the lowest quartile of microcystin-LR exposure, those in the highest quartile had significantly higher risks of abnormal BUN (OR = 1.80, 95% CI = 1.34-2.42), SCr (OR = 4.58, 95% CI = 2.92-7.21), and eGFR (OR = 4.41, 95% CI = 2.55-7.63), respectively, but no higher risk was found in subjects with higher AFB1 exposure. After adjustment for confounding factors, risk associations with microcystin-LR persisted. Consequently, our results suggest that microcystin, rather than aflatoxin, might be one important risk of renal-function impairment.

Hepatocellular carcinoma and the risk of occupational exposure

Hepatocellular carcinoma (HCC) is the most common type of liver cancer. The main risk factors for HCC are alcoholism, hepatitis B virus, hepatitis C virus, nonalcoholic steatohepatitis, obesity, type 2 diabetes, cirrhosis, aflatoxin, hemochromatosis, Wilson's disease and hemophilia. Occupational exposure to chemicals is another risk factor for HCC. Often the relationship between occupational risk and HCC is unclear and the reports are fragmented and inconsistent. This review aims to summarize the current knowledge regarding the association of infective and non-infective occupational risk exposure and HCC in order to encourage further research and draw attention to this global occupational public health problem.

Aflatoxin Exposure and Associated Human Health Effects, a Review of Epidemiological Studies

Aflatoxins are fungal toxins that possess acute life threatening toxicity, carcinogenic properties and other potential chronic adverse effects. Dietary exposure to aflatoxins is considered a major public health concern, especially for subsistence farming communities in sub-Saharan Africa and South Asia, where dietary staple food crops such as groundnuts and maize are often highly contaminated with aflatoxin due to hot and humid climates and poor storage, together with low awareness of risk and lack of enforcement of regulatory limits. Biomarkers have been developed and applied in many epidemiological studies assessing aflatoxin exposure and the associated health effects in these high-risk population groups. This review discusses the recent epidemiological evidence for aflatoxin exposure, co-exposure with other mycotoxins and associated health effects in order to provide evidence on risk assessment, and highlight areas where further research is necessary. Aflatoxin exposure can occur at any stage of life and is a major risk factor for hepatocellular carcinoma, especially when hepatitis B infection is present. Recent evidence suggests that aflatoxin may be an underlying determinant of stunted child growth, and may lower cell-mediated immunity, thereby increasing disease susceptibility. However, a causal relationship between aflatoxin exposure and these latter adverse health outcomes has not been established, and the biological mechanisms for these have not been elucidated, prompting further research. Furthermore, there is a dearth of information regarding the health effects of co-exposure to aflatoxin with other mycotoxins. Recent developments of biomarkers provide opportunities for important future research in this area.

Search for aflatoxin and trichothecene production inhibitors and analysis of their modes of action

Mycotoxin contamination of crops is a serious problem throughout the world because of its impact on human and animal health as well as economy. Inhibitors of mycotoxin production are useful not only for developing effective methods to prevent mycotoxin contamination, but also for investigating the molecular mechanisms of secondary metabolite production by fungi. We have been searching for mycotoxin production inhibitors among natural products and investigating their modes of action. In this article, we review aflatoxin and trichothecene production inhibitors, including our works on blasticidin S, methyl syringate, cyclo(l-Ala-l-Pro), respiration inhibitors, and precocene II.

Changing epidemiology of hepatocellular carcinoma in Asia

Hepatocellular carcinoma is a major problem in Asia because of the presence of multiple risk factors in the region such as endemicity of hepatitis B and significant contamination of foodstuff by aflatoxin in some areas. Another risk factor for HCC, chronic hepatitis C infection, in Asia is most significant in Japan, the only Asian country with more HCV than HBV-related hepatocellular carcinoma. As these risk factors can and are being modified by measures such as universal hepatitis B immunisation, successful treatment of HCV infections, reduction and improved surveillance of aflatoxin contamination of foodstuff, it is not surprising that the epidemiology of HCC in Asia is changing. All these are offset by the rising importance of NAFLD and NASH as chronic liver diseases and risk factors for HCC which contributes to the changing epidemiology of HCC in Asia.

Nutrition and Hepatocellular Cancer

BACKGROUND

Hepatocellular carcinoma (HCC) significantly contributes to the global burden of cancer. Liver cancer is the third most frequent cause of cancer-related death with HCC representing more than 90% of primary liver cancers. The majority of patients are not only affected by the malignant disease but do also suffer from chronic liver disease. Therefore, several factors impact on the prognosis of patients with HCC, including tumor-related factors, liver function and patient-related factors such as performance status and other comorbidities. The nutritional status is of high significance for the patients' performance status, the tolerance of tumor-targeting therapy and the prognosis of cancer of any type and is specially referenced in HCC. This overview is on current concepts on the role of nutritional factors in hepatocarcinogenesis and the role of nutrition in patients affected by HCC.

SUMMARY

Nutritional status and composition of diet are relevant factors related to the risk of HCC. They also have an important role concerning the prognosis of patients with HCC. Besides risk factors, several macro- and micronutrient components have been found to be inversely correlated with the risk of HCC. To prevent disease progression to liver cirrhosis or HCC in patients with nonalcoholic steatohepatitis, it is crucial to optimize the metabolic state.

KEY MESSAGE AND PRACTICAL IMPLICATION

Evidence from well-designed prospective interventional trials with the aim to reduce the HCC incidence or to prolong survival in patients with HCC based on nutritional modification is still to be generated.

Dietary mycotoxins, co-exposure, and carcinogenesis in humans: Short review

Mycotoxins, toxic secondary metabolites of fungi, affect global agriculture so prolifically that they are virtually ubiquitous at some concentration in the average human diet. Studies of in vitro and in vivo toxicity are discussed, leading to investigations of co-exposed mycotoxins, as well as carcinogenic effects. Some of the most common and toxicologically significant mycotoxins, such as the aflatoxins, ochratoxins, fumonisins, deoxynivalenol, T-2 toxin, HT-2 toxin, patulin, zearalenone, and some ergot alkaloids are outlined. The wide variety of pathogenic mechanisms these compounds employ are shown capable of inducing a complex set of interactions. Of particular note are potential synergisms between mycotoxins with regard to carcinogenic attributable risk, indicating an important field for future study.

Hepatocellular carcinoma: From clinical practice to evidence-based treatment protocols

Hepatocellular carcinoma (HCC) is one of the major malignant diseases in many healthcare systems. The growing number of new cases diagnosed each year is nearly equal to the number of deaths from this cancer. Worldwide, HCC is a leading cause of cancer-related deaths, as it is the fifth most common cancer and the third most important cause of cancer related death in men. Among various risk factors the two are prevailing: viral hepatitis, namely chronic hepatitis C virus is a well-established risk factor contributing to the rising incidence of HCC. The epidemic of obesity and the metabolic syndrome, not only in the United States but also in Asia, tend to become the leading cause of the long-term rise in the HCC incidence. Today, the diagnosis of HCC is established within the national surveillance programs in developed countries while the diagnosis of symptomatic, advanced stage disease still remains the characteristic of underdeveloped countries. Although many different staging systems have been developed and evaluated the Barcelona-Clinic Liver Cancer staging system has emerged as the most useful to guide HCC treatment. Treatment allocation should be decided by a multidisciplinary board involving hepatologists, pathologists, radiologists, liver surgeons and oncologists guided by personalized -based medicine. This approach is important not only to balance between different oncologic treatments strategies but also due to the complexity of the disease (chronic liver disease and the cancer) and due to the large number of potentially efficient therapies. Careful patient selection and a tailored treatment modality for every patient, either potentially curative (surgical treatment and tumor ablation) or palliative (transarterial therapy, radioembolization and medical treatment, i.e., sorafenib) is mandatory to achieve the best treatment outcome.

Early-life exposures to infectious agents and later cancer development

There is a growing understanding that several infectious agents are acquired in early life and this is the reason why available vaccines target the new born, infants, and adolescents. Infectious agents are associated with cancer development and it is estimated that about 20% of the world's cancer burden is attributed to infectious agents. There is a growing evidence that certain infectious agents acquired in early life can give rise to cancer development, but estimates of the cancer burden from this early‐life acquisition is unknown. In this article, we have selected five cancers (cervical, liver, Burkitt's lymphoma‐leukemia, nasopharyngeal carcinoma, and adult T‐cell leukemia‐lymphoma) and examine their links to infectious agents (HPV, HBV, HCV, EBV, and HTLV‐1) acquired in early life. For these agents, the acquisition in early life is from mother‐to‐child transmission, perinatal contact (with genital tract secretions, amniotic fluids, blood, and breast milk), saliva, sexual intercourse, and blood transfusion. We also discuss prevention strategies, address future directions, and propose mechanisms of action after a long latency period from the time of acquisition of the infectious agent in early life to cancer development.

Food Safety in Low and Middle Income Countries

Evidence on foodborne disease (FBD) in low and middle income countries (LMICs) is still limited, but important studies in recent years have broadened our understanding. These suggest that developing country consumers are concerned about FBD; that most of the known burden of FBD disease comes from biological hazards; and, that most FBD is the result of consumption of fresh, perishable foods sold in informal markets. FBD is likely to increase in LMICs as the result of massive increases in the consumption of risky foods (livestock and fish products and produce) and lengthening and broadening value chains. Although intensification of agricultural production is a strong trend, so far agro-industrial production and modern retail have not demonstrated clear advantages in food safety and disease control. There is limited evidence on effective, sustainable and scalable interventions to improve food safety in domestic markets. Training farmers on input use and good practices often benefits those farmers trained, but has not been scalable or sustainable, except where good practices are linked to eligibility for export. Training informal value chain actors who receive business benefits from being trained has been more successful. New technologies, growing public concern and increased emphasis on food system governance can also improve food safety.

Fish consumption doesn't reduce the risk of hepatocellular carcinoma

BACKGROUND

Several observational studies have investigated the association between fish consumption and the risk of hepatocellular carcinoma (HCC), however, the results were inconsistent. Hence, we performed a meta-analysis of observational studies to evaluate the effect of fish consumption on HCC risk.

METHODS

A systematic search was performed using the Pubmed, Embase, and Cochrane Library Central database for case-control and coshort studies that assessed fish intake and HCC risk. Fixed-effect and random-effect models were used to estimate summary relative risks (RR) and the corresponding 95% confidence intervals (CIs). Subgroup analyses and sensitivity analysis were also performed.

RESULTS

Nine case-control studies and three cohort studies were included, involving a total of 1,071,458 participants and 2,627 HCC cases. Meta-analysis showed that there was no association between fish consumption and a significant reduction in HCC incidence (RR = 0.85, 95% CI [0.62, 1.17]). In our subgroup analyses, the result was substantially affected by adjustment for hepatic viruses' infection status. Sensitivity analysis confirmed the stability of results. Furthermore, there was no evidence of publication bias as suggested by Begg's P value (P = 0.411) and Egger's (P = 0.596) test.

CONCLUSIONS

In conclusion, our results do not support a significant inverse association of fish consumption with HCC risk. More in-depth studies are warranted to report more detailed results, including stratified results by fish types, preparation methods, and gender.

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.

A major shift of viral and nutritional risk factors affects the hepatocellular carcinoma risk among Ivorian patients: a preliminary report

Hepatocellular carcinoma (HCC) is a major public health concern in Sub-Saharan Africa. Early research in Ivory Coast showed that chronic hepatitis B and aflatoxin B1 exposure were the two most important etiological agents of HCC in the country but, surprisingly, no survey analyzing HCC etiologies has been conducted since decades. In a preliminary report, we characterized for hepatitis B and C markers 30 consecutive cases of HCC recruited from Abidjan hospitals between June 2011 and December 2012. Nutritional and lifestyle features of patients were analyzed as well. The mean age of the patients was 53 ± 15 years with a sex ratio (M:F = 2.7). HBsAg was the most frequent viral marker in the series (63 %). All HBV isolates belonged to genotype E. With regards to regional standard, anti-HCV reached a very high level (47 %) in the present series. Hepatitis C was more frequent among patients living outside Abidjan (83 vs 23 %, P = 0.009). Patients living in Abidjan were significantly younger than individual living elsewhere in the country (48 ± 14 vs 60 ± 16 years old, P = 0.038) reflecting a possible role for local environmental pollution in tumor progression. Finally, we observed that patients born in Mandé/Gur-speaking regions (North) were younger (48 ± 14 vs 59 ± 15, P = 0.05) and consumed maize more frequently (80 vs 26 %, P = 0.009) than other patients. Interestingly, maize consumption was associated with a trend for aminotransferases elevation (mean = 1.7-1.8 fold, P = 0.06) suggesting a direct hepatic toxicity of this staple food in Ivory Coast. In conclusion, our work indicates that HCC epidemiology underwent recently major drifts in Ivory Coast.

The evolving epidemiology of hepatocellular carcinoma: a global perspective

Primary liver cancer, the majority of which are hepatocellular carcinomas, is now the second leading cause of cancer death worldwide. Hepatocellular carcinoma is a unique cancer that typically arises in the setting of chronic liver disease at a rate dependent upon the complex interplay between the host, disease and environmental factors. Infection with chronic hepatitis B or C virus is currently the dominant risk factor worldwide. However, changing lifestyle and environmental factors in western countries plus rising neonatal hepatitis B vaccination rates and decreasing exposure to dietary aflatoxins in developing countries are driving an evolution of the epidemiology of this cancer. An understanding of this change is crucial in combating the rising incidence currently being seen in western regions and will underpin the efforts to reduce the mortality rates associated with this cancer.

Reprint of: cancer "causation" by infections--individual contributions and synergistic networks

The search for infectious agents playing a role in human carcinogenesis and their identification remain important issues. This could provide clues for a broader spectrum of cancers preventable by vaccination and accessible to specific therapeutic regimens. Yet, the various ways of interacting among different factors functioning synergistically and their different modes of affecting individual cells should bring to question the validity of the term "causation". It also should put a word of caution into all attempts to summarize criteria for "causality" of infectious agents in cancer development. At least in the opinion of these authors, we would be much better off avoiding these terms, replacing "causal factor" by "risk factor" and grading them according to their contribution to an individual's cancer risk.

Attributable causes of liver cancer mortality and incidence in china

OBJECTIVES

To estimate the proportion of liver cancer cases and deaths due to infection with hepatitis B virus (HBV), hepatitis C virus (HCV), aflatoxin exposure, alcohol drinking and smoking in China in 2005.

STUDY DESIGN

Systemic assessment of the burden of five modifiable risk factors on the occurrence of liver cancer in China using the population attributable fraction.

METHODS

We estimated the population attributable fraction of liver cancer caused by five modifiable risk factors using the prevalence data around 1990 and data on relative risks from meta-analyses, and large-scale observational studies. Liver cancer mortality data were from the 3rd National Death Causes Survey, and data on liver cancer incidence were estimated from the mortality data from cancer registries in China and a mortality/incidence ratio calculated.

RESULTS

We estimated that HBV infection was responsible for 65.9% of liver cancer deaths in men and 58.4% in women, while HCV was responsible for 27.3% and 28.6% respectively. The fraction of liver cancer deaths attributable to aflatoxin was estimated to be 25.0% for both men and women. Alcohol drinking was responsible for 23.4% of liver cancer deaths in men and 2.2% in women. Smoking was responsible for 18.7% and 1.0% . Overall, 86% of liver cancer mortality and incidence (88% in men and 78% in women) was attributable to these five modifiable risk factors.

CONCLUSIONS

HBV, HCV, aflatoxin, alcohol drinking and tobacco smoking were responsible for 86% of liver cancer mortality and incidence in China in 2005. Our findings provide useful data for developing guidelines for liver cancer prevention and control in China and other developing countries.

Ochratoxin A and human health risk: a review of the evidence

Ochratoxin A (OTA) is a mycotoxin produced by several fungal species including Aspergillus ochraceus, A. carbonarius, A. niger, and Penicillium verrucosum. OTA causes nephrotoxicity and renal tumors in a variety of animal species; however, human health effects are less well-characterized. Various studies have linked OTA exposure with the human diseases Balkan endemic nephropathy (BEN) and chronic interstitial nephropathy (CIN), as well as other renal diseases. This study reviews the epidemiological literature on OTA exposure and adverse health effects in different populations worldwide, and assesses the potential human health risks of OTA exposure. Epidemiological studies identified in a systematic review were used to calculate unadjusted odds ratios for OTA associated with various health endpoints. With one exception, there appears to be no statistically significant evidence for human health risks associated with OTA exposure. One Egyptian study showed a significantly higher risk of nephritic syndrome in those with very high urinary OTA levels compared with relatively unexposed individuals; however, other potential risk factors were not controlled for in the study. Larger cohort or case-control studies are needed in the future to better establish potential OTA-related human health effects, and further duplicate-diet studies are needed to validate biomarkers of OTA exposure in humans.

Global impacts of aflatoxin in maize: trade and human health

Maize is one of the most important agricultural commodities worldwide in terms of amounts produced, consumed, and traded. Hence, naturally occurring aflatoxin contamination in maize has important ramifications for both global trade and health. Aflatoxin is produced by certain species of the genus Aspergillus in a variety of food crops, including maize, peanuts, and tree nuts. Over 100 nations have aflatoxin regulations, which are intended to protect human and animal health, but also incur economic losses to nations that attempt to export maize and other aflatoxin-contaminated commodities. These economic effects must be balanced against the health protection afforded by the regulations. It is important to acknowledge that, even in nations that have aflatoxin regulations, many individuals consume maize that has undergone no regulatory inspection, especially in nations where subsistence farming is widespread. Hence, aflatoxin contamination, exposure, and lack of regulation can also contribute to adverse effects on trade and health worldwide. This review, part of a special issue on aflatoxin in maize, describes economic and health effects of aflatoxin in maize on a global level. It ends with a story of an intervention that reduced maize consumption in one population in China, which is likely the main determinant of the reduction in liver cancer mortality in that population over the last 30 years, from reduced aflatoxin exposure.

Natural Occurrence of Mycotoxins in Food and Feed: Pakistan Perspective

Fungi are commonly present in the environment and can grow under favorable conditions on an extensive variety of substrates. During harvesting, handling, storage, and distribution, agricultural commodities are subjected to infection by toxigenic molds, which may cause spoilage and produce toxic metabolites called mycotoxins. Fungal contamination of various food commodities with consequent exposure of the community to mycotoxins is a hazard that may exist depending on environmental factors, crop health, and soil conditions. Mycotoxins represent serious consequences due to substantial economic loss and risk to health. The environmental conditions of Pakistan with its mostly warm temperature are conducive to growth of toxigenic fungi resulting in mycotoxin production in different food items. Moreover, the poor conditions of storage and deficiency in regulatory measures in food quality control worsen the situation in the country. This review encompasses mycotoxin contamination of food and feed in Pakistan. High concentrations of mycotoxins are found in some commodities that are used on a daily basis in Pakistan, which may be a concern depending on dietary variety and health conditions of individuals in the population. Therefore, the mycotoxin contamination of foodstuff with exceeding levels represents a serious health hazard for the local population. There is a need to conduct more studies to analyze mycotoxin occurrence in all types of food commodities throughout the country. For consumer safety and the country's economy, the regulatory authorities should take into account this issue of contamination, and control strategies should be implemented and the quality control system of food improved.

Cancer "causation" by infections--individual contributions and synergistic networks

The search for infectious agents playing a role in human carcinogenesis and their identification remain important issues. This could provide clues for a broader spectrum of cancers preventable by vaccination and accessible to specific therapeutic regimens. Yet, the various ways of interacting among different factors functioning synergistically and their different modes of affecting individual cells should bring to question the validity of the term "causation". It also should put a word of caution into all attempts to summarize criteria for "causality" of infectious agents in cancer development. At least in the opinion of these authors, we would be much better off avoiding these terms, replacing "causal factor" by "risk factor" and grading them according to their contribution to an individual's cancer risk.

Hepatocellular carcinoma epidemiology

Primary liver cancer (namely hepatocellular carcinoma, HCC) is worldwide the fifth most common cancer in men and the seventh one in women, and it represents the third most frequent cause of cancer death. HCC rates are particularly high in eastern/south-eastern Asia and in Africa, intermediate in Southern Europe, and low in most high-income countries. Persistent infections by HBV or HCV are the main recognized risk factors for HCC. Aflatoxin exposure is also an important risk factor for HCC development in Africa and eastern Asia. In high-income countries heavy alcohol drinking, tobacco smoking, overweight, diabetes, familial/genetic factors, and selected dietary aspects, have a relevant role. Updated geographic patterns and time trends in mortality from HCC in Europe, USA, Japan, and Australia are provided in the present review, together with an overview of relevant etiologic factors for HCC and main measures for the prevention of this neoplasm.

Reduced foodborne toxin exposure is a benefit of improving dietary diversity

Naturally occurring foodborne toxins are common in subsistence diets of low-income human populations worldwide. Often, these populations rely on one or two staple foods for the bulk of their calories, making them more susceptible to chronic intake of certain toxins. Exposure to common foodborne toxins is associated with diverse conditions such as cancer, immunotoxicity, growth impairment, and neurological deficits. Interventions focused solely on reducing toxin levels have proven difficult to sustain. Using case studies of two foodborne toxins, aflatoxin and cassava cyanide, this article addresses the heightened risk of particular diseases from eating monotonous diets based in maize, groundnuts, and cassava: common in sub-Saharan Africa and parts of Asia. We also discuss the potential role of increased dietary diversity in counteracting these diseases. Increased dietary diversity can reduce consumption of toxins and increase intake of nutrients that could counteract the toxicity of such chemicals. In Qidong, China, a population that previously consumed a monotonous maize-based diet and increased dietary diversity since the 1980s has experienced a dramatic reduction in liver cancer mortalities. That liver cancer decreased as dietary diversity increased is the catalyst for the hypothesis that dietary diversity could have a direct impact on reducing health effects of foodborne toxins. Future research, agricultural development, and food policy reforms should take into consideration the multifaceted benefits associated with improved dietary diversity. Collaborations between toxicologists, nutritionists, and policymakers are important to development of sustainable interventions to reduce foodborne toxin exposure and promote health through increased dietary diversity.

Susceptibility to aflatoxin contamination among maize landraces from Mexico

Maize, the critical staple food for billions of people, was domesticated in Mexico about 9,000 YBP. Today, a great array of maize landraces (MLRs) across rural Mexico is harbored in a living library that has been passed among generations since before the establishment of the modern state. MLRs have been selected over hundreds of generations by ethnic groups for adaptation to diverse environmental settings. The genetic diversity of MLRs in Mexico is an outstanding resource for development of maize cultivars with beneficial traits. Maize is frequently contaminated with aflatoxins by Aspergillus flavus, and resistance to accumulation of these potent carcinogens has been sought for over three decades. However, MLRs from Mexico have not been evaluated as potential sources of resistance. Variation in susceptibility to both A. flavus reproduction and aflatoxin contamination was evaluated on viable maize kernels in laboratory experiments that included 74 MLR accessions collected from 2006 to 2008 in the central west and northwest regions of Mexico. Resistant and susceptible MLR accessions were detected in both regions. The most resistant accessions accumulated over 99 % less aflatoxin B1 than did the commercial hybrid control Pioneer P33B50. Accessions supporting lower aflatoxin accumulation also supported reduced A. flavus sporulation. Sporulation on the MLRs was positively correlated with aflatoxin accumulation (R = 0.5336, P < 0.0001), suggesting that resistance to fungal reproduction is associated with MLR aflatoxin resistance. Results of the current study indicate that MLRs from Mexico are potentially important sources of aflatoxin resistance that may contribute to the breeding of commercially acceptable and safe maize hybrids and/or open pollinated cultivars for human and animal consumption.

Hepatocellular carcinoma: epidemiology and risk factors

Hepatocellular carcinoma is one of the major malignant tumors in the world today. The number of new cases of the tumor increases year by year, and hepatocellular carcinoma almost always runs a fulminant course and carries an especially grave prognosis. It has a low resectability rate and a high recurrence rate after surgical intervention, and responds poorly to anticancer drugs and radiotherapy. Hepatocellular carcinoma does not have a uniform geographical distribution: rather, very high incidences occur in Eastern and Southeastern Asia and in sub-Saharan Black Africans. In these regions and populations, the tumor shows a distinct shift in age distribution toward the younger ages, seen to greatest extent in sub-Saharan Black Africans. In all populations, males are more commonly affected. The most common risk factors for hepatocellular carcinoma in resource-poor populations with a high incidence of the tumor are chronic hepatitis B virus infection and dietary exposure to the fungal hepatocarcinogen aflatoxin B1. These two causative agents act either singly or synergistically. Both the viral infection and exposure to the fungus occur from early childhood, and the tumor typically presents at an early age. Chronic hepatitis C virus infection is an important cause of hepatocellular carcinoma in resource-rich countries with a low incidence of the tumor. The infection is acquired in adulthood and hepatocellular carcinoma occurs later than it does with hepatitis B virus-induced tumors. In recent years, obesity and the metabolic syndrome have increased markedly in incidence and importance as a cause of hepatocellular carcinoma in some resource-rich regions. Chronic alcohol abuse remains an important risk factor for malignant transformation of hepatocytes, frequently in association with alcohol-induced cirrhosis. Excessive iron accumulation in hereditary hemochromatosis and dietary iron overload in the Black African population and membranous obstruction of the inferior cava cause the tumor in a few countries.

The conundrum of causality in tumor virology: the cases of KSHV and MCV

Controversy has plagued tumor virology since the first tumor viruses were described over 100 years ago. Methods to establish cancer causation, such as Koch's postulates, work poorly or not at all for these viruses. Kaposi's sarcoma herpesvirus (KSHV/HHV8) and Merkel cell polyomavirus (MCV) were both found using nucleic acid identification methods but they represent opposite poles in the patterns for tumor virus epidemiology. KSHV is uncommon and has specific risk factors that contribute to infection and subsequent cancers. MCV and Merkel cell carcinoma (MCC), in contrast, is an example in which mutations to our normal viral flora contribute to cancer. Given the near-ubiquity of human MCV infection, establishing cancer causality relies on molecular evidence that does not fit comfortably within traditional infectious disease epidemiological models. These two viruses reveal some of the challenges and opportunities for inferring viral cancer causation in the age of molecular biology.

Isoquercitrin inhibits the progression of liver cancer in vivo and in vitro via the MAPK signalling pathway

Liver cancer is a malignant tumour with high morbidity and fatality rates that is common worldwide. At present, the clinical approaches to treating primary liver cancer include partial hepatectomy, systemic or local chemotherapy, radiotherapy, radiofrequency ablative surgery and liver transplantation. However, all of these approaches have shortcomings, including poor prognosis and numerous side-effects. A large number of studies have proven that many effective ingredients in traditional Chinese medicine, particularly the flavonoid compounds extracted from plants, have achieved breakthroughs in terms of enhancing the effects and reducing the toxicity of chemotherapy and radiotherapy, preventing tumour metastasis and relapse after surgery, alleviating the clinical symptoms of advanced tumours, improving the quality of life of the patient with tumours and extending patient long‑term survival. The purpose of the present study was to investigate the impact of isoquercitrin, the flavonoid from Bidens bipinnata L. extract, on the progression of liver cancer and to achieve a deeper understanding of the biological characteristics of isoquercitrin's involvement in the progression of liver cancer. In the in vitro experiments, isoquercitrin was found to strongly inhibit the proliferation of human liver cancer cells, promote the apoptosis of human liver cancer cells, and block the cell cycle in the G1 phase. Isoquercitrin activated caspase-3, -8 and -9, inhibited the expression level of ERK and p38MAPK protein phosphorylation, and promoted the phosphorylation of JNK. Additionally, isoquercitrin reduced the expression level of PKC in human liver cancer cells. In the in vivo experiments, isoquercitrin was also found to significantly inhibit the growth of transplanted tumours in nude mice. The present study confirmed that isoquercitrin could inhibit the progression of human liver cancer in vivo and in vitro, and the molecular mechanism of isoquercitrin may be closely associated with the MAPK and PKC signalling pathways.

Aflatoxin regulations and global pistachio trade: insights from social network analysis

Aflatoxins, carcinogenic toxins produced by Aspergillus fungi, contaminate maize, peanuts, and tree nuts in many regions of the world. Pistachios are the main source of human dietary aflatoxins from tree nuts worldwide. Over 120 countries have regulations for maximum allowable aflatoxin levels in food commodities. We developed social network models to analyze the association between nations' aflatoxin regulations and global trade patterns of pistachios from 1996-2010. The main pistachio producing countries are Iran and the United States (US), which together contribute to nearly 75% of the total global pistachio market. Over this time period, during which many nations developed or changed their aflatoxin regulations in pistachios, global pistachio trade patterns changed; with the US increasingly exporting to countries with stricter aflatoxin standards. The US pistachio crop has had consistently lower levels of aflatoxin than the Iranian crop over this same time period. As similar trading patterns have also been documented in maize, public health may be affected if countries without aflatoxin regulations, or with more relaxed regulations, continually import crops with higher aflatoxin contamination. Unlike the previous studies on maize, this analysis includes a dynamic element, examining how trade patterns change over time with introduction or adjustment of aflatoxin regulations.

Role of RASSF1A promoter methylation in the pathogenesis of hepatocellular carcinoma: a meta-analysis of 21 cohort studies

We carried out the current meta-analysis aiming to comprehensively assess the potential role of RASSF1A aberrant promoter methylation in the pathogenesis of hepatocellular carcinoma (HCC). A range of electronic databases were searched: Web of Science (1945-2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966-2013), EMBASE (1980-2013), CINAHL (1982-2013) and the Chinese Biomedical Database (CBM) (1982-2013) without language restrictions. Meta-analysis was conducted using the STATA 12.0 software. Crude risk difference (RD) with their 95% confidence interval (95% CI) was calculated. In the present meta-analysis, 21 clinical cohort studies with a total of 1,205 HCC patients were included. The results of our meta-analysis illustrated that the frequency of RASSF1A promoter methylation in cancer tissues were significantly higher than those of normal, adjacent and benign tissues (cancer tissues vs. normal tissues: RD = 0.63, 95% CI 0.53-0.73, P < 0.001; cancer tissues vs. adjacent tissues: RD = 0.43, 95% CI 0.33-0.53, P < 0.001; cancer tissues vs. benign tissues: RD = 0.48, 95% CI 038-0.58, P < 0.001; respectively). Further subgroup by ethnicity demonstrated that RASSF1A aberrant promoter methylation was correlated with the pathogenesis of HCC among both Asians and Caucasians (all P < 0.05). The current meta-analysis suggests that RASSF1A aberrant promoter methylation may be implicated in the pathogenesis of HCC. Thus, detection of RASSF1A promoter methylation may be a helpful and valuable biomarker for diagnosis and prognosis of HCC.

Effects of β-glucan on some environmental toxins: An overview

BACKGROUND

Beta-glucans are naturally occurring polysaccharides and constituents of the cell wall of certain pathogenic bacteria and fungi. They have proven healing and immunostimulating properties, linked to enhanced macrophage and natural killer cell function which likely involves specific interaction with several cell surface receptors, such as lactosylceramide, selected scavenger receptors, and dectin-1 (betaGR). In particular, glucan reduces the immunosuppressive effects of a number of agents including chemo therapy and radiation. More recent studies suggest a positive function for glucan in the immunosuppression caused by toxic agents in the environment.

AIM

An overview of the effects of glucan on the mycotoxin, aflotoxin and other environmental toxins (mercury-thimerosal, depleted uranium).

CONCLUSION

Glucan is effective as a natural immunomodulator and could be used as an inexpensive solution to reducing the adverse effects of some environmental toxins.

Ablation therapy for hepatocellular carcinoma: past, present and future perspectives

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide, and is most commonly found in the setting of liver cirrhosis. Treatment of HCC must consider both the tumors present, as well as the remaining dysfunctional liver that both hinders treatment and can produce additional HCC over time. Ablation is an evolving part of the multimodality treatment approach to HCC that can effectively destroy tumors while preserving surrounding liver parenchyma. New technologies have made ablation an indispensable tool in the treatment of all stages of HCC. This review presents the history, present technologies and future potential of ablation in the treatment of HCC.