The case for aflatoxins in the causal chain of gallbladder cancer

Mycotoxins and consumers' awareness: Recent progress and future challenges

While food shortages have become an important challenge, providing safe food resources is a point of interest on a global scale. Mycotoxins are secondary metabolites that are formed through various fungi species. They are mainly spread through diets such as food or beverages. About one quarter of the world's food is spoiled with mycotoxins. As this problem is not resolved, it represents a significant threat to global food security. Besides the current concerns regarding the contamination of food items by these metabolites, the lack of knowledge by consumers and their possible growth and toxin production attracted considerable attention. While globalization provides a favorite condition for some countries, food security still is challenging for most countries. There are various approaches to reducing the mycotoxigenic fungi growth and formation of mycotoxins in food, include as physical, chemical, and biological processes. The current article will focus on collecting data regarding consumers' awareness of mycotoxins. Furthermore, a critical overview and comparison among different preventative approaches to reduce risk by consumers will be discussed. Finally, the current effect of mycotoxins on global trade, besides future challenges faced by mycotoxin contamination on food security, will be discussed briefly.

Recent advances in microbial toxin-related strategies to combat cancer

It is a major concern to treat cancer successfully, due to the distinctive pathophysiology of cancer cells and the gradual manifestation of resistance. Specific action, adverse effects and development of resistance has prompted the urgent requirement of exploring alternative anti-tumour treatment therapies. The naturally derived microbial toxins as a therapy against cancer cells are a promisingly new dimension. Various important microbial toxins such as Diphtheria toxin, Vibrio cholera toxin, Aflatoxin, Patulin, Cryptophycin-55, Chlorella are derived from several bacterial, fungal and algal species. These agents act on different biotargets such as inhibition of protein synthesis, reduction in cell growth, regulation of cell cycle and many cellular processes. Bacterial toxins produce actions primarily by targeting protein moieties and some immunomodulation and few acts through DNA. Fungal toxins appear to have more DNA damaging activity and affect the cell cycle. Algal toxins produce alteration in mitochondrial phosphorylation. In conclusion, microbial toxins and their metabolites appear to have a great potential to provide a promising option for the treatment and management to combat cancer.

Environmental and Lifestyle Risk Factors in the Carcinogenesis of Gallbladder Cancer

Gallbladder cancer (GBC) is an aggressive neoplasm that in an early stage is generally asymptomatic and, in most cases, is diagnosed in advanced stages with a very low life expectancy because there is no curative treatment. Therefore, understanding the early carcinogenic mechanisms of this pathology is crucial to proposing preventive strategies for this cancer. The main risk factor is the presence of gallstones, which are associated with some environmental factors such as a sedentary lifestyle and a high-fat diet. Other risk factors such as autoimmune disorders and bacterial, parasitic and fungal infections have also been described. All these factors can generate a long-term inflammatory state characterized by the persistent activation of the immune system, the frequent release of pro-inflammatory cytokines, and the constant production of reactive oxygen species that result in a chronic damage/repair cycle, subsequently inducing the loss of the normal architecture of the gallbladder mucosa that leads to the development of GBC. This review addresses how the different risk factors could promote a chronic inflammatory state essential to the development of gallbladder carcinogenesis, which will make it possible to define some strategies such as anti-inflammatory drugs or public health proposals in the prevention of GBC.

Knowledge and Behavioral Habits to Reduce Mycotoxin Dietary Exposure at Household Level in a Cohort of German University Students

Mycotoxins pose a health concern for humans. Therefore, strategies at pre- and post-harvest and maximum levels for food have been implemented, aimed to minimize the risk of dietary exposure. Yet, consumers’ dietary habits and life style play a substantial role in overall exposure. The aim of this study was to investigate knowledge of mycotoxins and accordance to behavioral practices or habits that may affect the risk of mycotoxin dietary exposure at the household level or when food commodities are obtained from non-regulated trade markets. For this purpose, an online survey was applied to a university student cohort (n = 186). The survey consisted of 23 questions grouped in five categories: Socio-demographic and income data, general life style and habits, knowledge about mycotoxins, compliance with the “17 golden rules to prevent mycotoxin contamination” of the German Federal Institute for Risk Assessment (BfR), and measures towards reducing health risks. We paid particular attention to knowledge and compliance of a group acquiring food items in markets outside regulation and surveillance, namely, adherents of food movements such as food sharing or dumpster diving. The results of our study indicate a generally rather low level of knowledge about mycotoxins in the investigated cohort, as well as a weak perception of their associated risks compared to similar studies; around half of the cohort was unfamiliar with the term “mycotoxin” and the health risks of mycotoxins were considered comparable to those of pesticides, heavy metals, microplastics and food additives. We observed, in general, a relatively high degree of compliance with the proposed golden rules. The rules with the highest compliance related to deteriorated foods with visible signs of fungal infestation, probably because these are already considered as food waste. Rules that were less followed included those that require a specific knowledge of food storage and early fungal contamination stages, namely preventive measures related to storage of bread. Adherents of food movements did not differ significantly with the control group in terms of knowledge, risk perception and compliance with the 17 golden rules. This may be due to the homogeneity of the cohort in terms of demography, age and educational level. However, significant low compliance in the food movements group was observed with the rules “Buy fruit and vegetables that are as intact as possible, i.e., without injuries and bruises” and “Rotten fruit should neither be eaten nor further processed into compote or jam”, possibly because of ideological convictions around reducing food waste. In conclusion, mycotoxin prevention strategies should not end at the retail level; in particular, clarification and information regarding health risk from mycotoxins are suggested in order to reduce the risk of exposure in private households or in informal trade markets. The results of this study should, however, be interpreted with caution due to the specific characteristics of the cohort in terms of age and educational level and the disparity in size between the control and the food movement group. This study is a starting point for evaluating and understanding the consumer perspective on mycotoxins.

Assessment of Mycotoxin Exposure in a Rural County of Chile by Urinary Biomarker Determination

Aflatoxin B1 (AFB1), ochratoxin A (OTA), zearalenone (ZEN), and deoxynivalenol (DON) are frequent mycotoxins that may cause carcinogenic, mutagenic, estrogenic, or gastrointestinal effects. The aim of this study was to assess the exposure to and risk from AFB1, OTA, ZEN, and DON in 172 participants of the Maule Cohort (MAUCO) by a biomarker analysis in urine and to associate their exposure with food consumption and occupation. Mycotoxins in the first morning urine were analyzed by solid-phase extraction and quantified by Ultra-High-Performance Liquid Chromatography with a mass-mass detector. Participants' information regarding food consumption, occupation, and other characteristics was obtained from a baseline and 2-year follow-up survey of the cohort. The prevalence and mean levels of mycotoxins in the urine were as follows: DON 63%, 60.7 (±78.7) ng/mL; AFB1 8%, 0.3 (±0.3) ng/mL; α-zearalenol (α-ZEL) 4.1%, 41.8 (±115) ng/mL; β-ZEL 3.5%, 17.4 (±16.1) ng/mL; AFM1 2%, 1.8 (±1.0) ng/mL; OTA 0.6% (1/172), 1.3 ng/mL; and ZEN 0.6%, 1.1 ng/mL. These results were translated into exposures of DON, ZEN, and aflatoxins of public health concern. Participants who consumed coffee and pepper the day before had a significantly greater presence of DON (OR: 2.3, CI95 1.17-4.96) and total ZEL (OR: 14.7, CI95 3.1-81.0), respectively, in their urine. Additionally, we observed associations between the habitual consumption of beer and DON (OR: 2.89, CI95 1.39-6.42). Regarding the levels of mycotoxins and the amount of food consumed, we found correlations between DON and nuts (p = 0.003), total ZEL and cereals (p = 0.01), and aflatoxins with capsicum powder (p = 0.03) and walnuts (p = 0.03). Occupation did not show an association with the presence of mycotoxins in urine.

An overview on possible links between aflatoxin B1 exposure and gallbladder cancer

Gallbladder cancer (GBC) is one of the most common sites for biliary tract cancers. It has a worldwide distribution being endemic in South America and Southern Asia. These high GBC rates have previously been linked to the determinants of health such as nutrition, genetics, lifestyle, and environment. Exposure to aflatoxin B₁ (AFB₁), a human carcinogen, is suggested to be involved with GBC development. This work aims to analyse the interplay of social, lifestyle, and genetic predisposing factors to GBC. AFB₁ plays a pivotal role in carcinogenic onset by genetic and epigenetic modifications. AFB₁ can induce molecular changes involved in the GBC pathogenesis, such as overexpression of UCHL1 gene, mutagenesis of TP53 gene, abnormal expression of oncogenes BCL-2, and aberrantly methylation of ERBB family receptors. However, a large-scale scientific cooperation is needed to confirm these molecular links through which AFB₁ may increase the GBC risk. For that, monitoring AFB₁ exposure through AF-albumin and AFB1-lysine will clarify the level of exposure of the population to AFB₁ in the GBC hotspot. Further, analyses of AFB1-adduct concentrations in GBC cases (fatal and non-fatal) are needed to understanding if AF contamination can trigger gallbladder cancer.

Probabilistic dietary based estimation of the burden of aflatoxin-induced hepatocellular carcinoma among adult Malawians

The risk of aflatoxin-induced hepatocellular carcinoma (HCC) among adults (average body weight of 60 kg) in Malawi was assessed based on aflatoxin B1 (AFB1) exposure through groundnut and maize consumption, by Monte Carlo simulation. The risk (cases per year per 100,000 people) of aflatoxin-induced HCC was estimated based on the AFB1 exposures estimated by this study and hepatitis B virus infection prevalence published for Malawi. AFB1 exposures were estimated by probabilistically combining data of AFB1 contamination in 338 groundnut and 604 maize samples with data of per capita groundnut and maize consumption in 274 households. Aflatoxins in the samples were analysed using validated LC-MS/MS, HPLC and VICAM based methods. The groundnut and maize consumption survey was based on household expenditure technique. The simulated mean AFB1 exposures through consumption of groundnuts, maize, and combination thereof were 28±65, 42±174, and 71±211 ng/kg. body weight (bw)/day, respectively. The estimated HCC risks were 1.26±2.72, 1.86±6.66 and 3.10±6.85 cases per 100,000 persons per year, respectively. Further, hypothetical eradication of hepatitis B virus (HBV) reduced the risk of HCC by 78%. This reaffirms the need for integrating HBV vaccination in the fight of aflatoxin induced HCC.

Gallbladder cancer: review of a rare orphan gastrointestinal cancer with a focus on populations of New Mexico

Gallbladder cancer is a rare malignancy of the biliary tract with a poor prognosis, frequently presenting at an advanced stage. While rare in the United States overall, gallbladder cancer has an elevated incidence in geographically distinct locations of the globe including Chile, North India, Korea, Japan and the state of New Mexico in the United States. People with Native American ancestry have a much elevated incidence of gallbladder cancer compared to Hispanic and non-Hispanic white populations of New Mexico. Gallbladder cancer is also one of the few bi-gendered cancers with an elevated female incidence compared to men. Similar to other gastrointestinal cancers, gallbladder cancer etiology is likely multi-factorial involving a combination of genomic, immunological, and environmental factors. Understanding the interplay of these unique epidemiological factors is crucial in improving the prevention, early detection, and treatment of this lethal disease. Previous studies have failed to identify a distinct genomic mutational profile in gallbladder cancers, however, work to identify promising clinically actionable targets is this form of cancer is ongoing. Examples include, interest in the HER2/Neu signaling pathway and the recognition that chronic inflammation plays a crucial role in gallbladder cancer pathogenesis. In this review, we provide a comprehensive overview of gallbladder cancer epidemiology, risk factors, pathogenesis, and treatment with a specific focus on the rural and Native American populations of New Mexico. We conclude this review by discussing future research directions with the goal of improving clinical outcomes for patients of this lethal malignancy.

Association of Aflatoxin and Gallbladder Cancer

BACKGROUND & AIMS

Aflatoxin, which causes hepatocellular carcinoma, may also cause gallbladder cancer. We investigated whether patients with gallbladder cancer have higher exposure to aflatoxin than patients with gallstones.

METHODS

We measured aflatoxin B1 (AFB1)-lysine adducts in plasma samples from the Shanghai Biliary Tract Cancer case-control study, conducted from 1997 through 2001. We calculated age- and sex-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) and the population-attributable fraction for 209 patients with gallbladder cancer and gallstones vs 250 patients with gallstones without cancer (controls). In 54 patients with gallbladder cancer, tumor tissue was examined for the R249S mutation in TP53, associated with aflatoxin exposure, through targeted sequencing.

RESULTS

The AFB1-lysine adduct was detected in 67 (32%) of 209 patients with gallbladder cancer and 37 (15%) of the 250 controls (χ2 P < .0001), almost threefold more patients with gallbladder cancer than controls (OR, 2.71; 95% CI, 1.70-4.33). Among participants with detectable levels of AFB1-lysine, the median level of AFB1-lysine was 5.4 pg/mg in those with gallbladder cancer, compared with 1.2 pg/mg in controls. For patients in the fourth quartile of AFB1-lysine level vs the first quartile, the OR for gallbladder cancer was 7.61 (95% CI, 2.01-28.84). None of the 54 gallbladder tumors sequenced were found to have the R249S mutation in TP53. The population-attributable fraction for cancer related to aflatoxin was 20% (95% CI, 15%-25%).

CONCLUSIONS

In a case-control study of patients with gallbladder cancer and gallstones vs patients with gallstones without cancer, we associated exposure to aflatoxin (based on plasma level of AFB1-lysine) with gallbladder cancer. Gallbladder cancer does not appear associate with the R249S mutation in TP53. If aflatoxin is a cause of gallbladder cancer, it may have accounted for up to 20% of the gallbladder cancers in Shanghai, China, during the study period, and could account for an even higher proportion in high-risk areas. If our findings are verified, reducing aflatoxin exposure might reduce the incidence of gallbladder cancer.

Cancer of the gallbladder-Chilean statistics

Chile has the world's highest rate of incidence as well as death from cancer of the gallbladder and biliary ducts. The problem is most acute in the southern provinces. These areas constitute the low average income associated with low educational attainment and a high rate of obesity compared with the rest of Chile. We could also include genetic factors related to processes of lithogenesis to these elements which are more common among the Mapuche. This population sub-group could benefit from special government programmes for early diagnosis and treatment of lithiasic disease and for the management of risk factors such as obesity. In this way, we could reduce the mortality rate of gallbladder cancer.