TP53 R249S mutations, exposure to aflatoxin, and occurrence of hepatocellular carcinoma in a cohort of chronic hepatitis B virus carriers from Qidong, China

Determination of aflatoxin M1 and ochratoxin A in breast milk in rural centers of Yazd, Iran: Exposure assessment and risk characterization

Breast milk (BM) is considered as the best source of nutrition which could have prevention effects on various diseases in the first years of a child. Along with nutritive compounds, presence of contaminants such as mycotoxins in BM could be transmitted into neonate. The aim of this study was to determine the occurrence, levels, and factors associated with the presence of aflatoxin M1 (AFM1) and ocratoxin a (OTA) in BM samples of nursing mothers in rural centers of Yazd, Iran. The presence and average AFM1 and OTA concentration in 72 BM samples was measured by competitive ELISA. The demographic and diet parameters of nursing mothers were collected by a questionnaire and were analyzed using SPSS 18 software. AFM1 and OTA were detected in 63 (87.5%) and 47 (65.2%) samples with the mean concentration levels of 19.46 ± 13.26 ng/L (ranges from 5.1 to 53.9) and 200 ± 160 ng/L (ranges from 100 to 2460), respectively. Of these, 32 samples (50.7%) for AFM1 and 23 samples (48.9%) for OTA had values exceeding the limit set by the European Union regulation for infant foods (25 ng/L for AFM1 and 500 ng/L for OTA). It was also found that the risk of AFM1 and OTA occurrence in BM increased significantly with the consumption of beans, bread, cereals, fruit juice and crackers, and cream, respectively. This study showed that the estimated daily intake for AFM1 and OTA by 1 month of age infants was 2.7 and 28.5 ng/kg bw/day, respectively, while, as the age of the infant increased, the values were lower and close to 0.9 and 9.9 ng/kg bw/day for AFM1 and OTA in 12 months of age infants, respectively. The high occurrence and noticeable levels of AFM1 and OTA detected in this study indicated that some infants receive undesirable exposures to AFM1 and OTA with breast milk. Therefore, it is recommended that mothers are advised to avoid certain foods during pregnancy and breastfeeding that are likely sources of mycotoxins.

First Molecular Characterization of Chronic Hepatitis B Carriers in Timbuktu, Mali

In Mali, hepatocellular carcinoma (HCC) is the third and sixth most common cancer in men and women, respectively. Mali comprises several distinct climato-ecological zones. Most studies to date have been conducted in the sub-Sahelian zone of southern Mali, including the capital city Bamako. In this part of the country, the main risk factors for HCC are chronic hepatitis B virus (HBV) carriage and dietary exposure to aflatoxins, a well-known hepatocarcinogen. Data are scarce for other ecological zones, but our preliminary data from 721 blood donors in the area of Timbuktu, presented in this study, suggest that chronic HBV carriage is also endemic in the northern Saharan zone of Mali. For further study, 29 healthy HBV chronic carrier volunteers were recruited from the blood transfusion center in Timbuktu. Successful viral genotyping in 20 volunteers revealed HBV genotype E in 13 cases and D in 7 cases, suggesting that this geographical and anthropological transition zone may also represent a transition zone between HBV genotypes that dominate sub-Saharan and northern Africa, respectively. Sequencing of circulating cell-free plasma DNA (cfDNA) from donors did not reveal the presence of the TP53 R249S mutation in these donors, a marker of dietary exposure to aflatoxins in sub-Saharan Africa. These results suggest that the geo-epidemiological distribution of the risk factors for HCC is not uniform across Mali, but is dependent upon climatic, socioeconomic and anthropological factors that might have an impact on patterns of chronic liver disease and cancer.

Current cancer burden in China: epidemiology, etiology, and prevention

Cancer has become the most common cause of death in China. Owing to rapid economic development, improved livelihood, and shifts in risk factors, cancer epidemiology has experienced substantial changes during the past several decades. In this review, we aim to describe the current cancer epidemiology of the main types of cancer in China, report major risk factors associated with cancer development, and summarize the contributions of the Chinese government to controlling the cancer burden. A total of 4,064,000 new cases were diagnosed in China in 2016. The most frequent types are lung cancer (828,100; 20.4%), colorectal cancer (408,000; 10.0%), and gastric cancer (396,500; 9.8%). Lung (657,000; 27.2%), liver (336,400, 13.9%), and stomach (288,500; 12.0%) cancers are the 3 most deadly cancers in the general population. The 5-year survival rate for cancer has dramatically increased in recent decades. However, liver and particularly pancreatic cancers still have the poorest prognosis. The main modifiable risk factors associated with cancer development include infectious agents, smoking, alcohol consumption, obesity, unhealthful dietary habits, and inadequate physical activity. The Chinese government has made unremitting efforts to decrease the cancer burden, including cancer education and investment in cancer screening programs.

Peripheral Blood Genetic Biomarkers for the Early Diagnosis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and has high mortality. Biomarkers related to HCC, such as alpha-fetoprotein, and imaging technology, such as ultrasound and computed tomography, have been used to screen and monitor HCC, but HCC is still difficult to diagnose effectively in the early stage due to the low sensitivity of the above mentioned traditional methods. There is an urgent need for noninvasive biomarkers to facilitate the screening and early diagnosis of HCC. With the advancement of next-generation sequencing, genetic biomarkers are becoming the core of cancer diagnosis. Genetic biomarkers such as peripheral blood circulating tumor DNA, microRNAs, long noncoding RNAs, circular RNAs, and exosomes have become the focus of early HCC diagnostics. HCC genetic biomarkers have been implemented in clinical practice. In this review, we describe the available literature on peripheral blood genetic biomarkers in the diagnosis of early HCC.

Liver cancer mortality over six decades in an epidemic area: what we have learned

BACKGROUND AND AIMS

Liver cancer is one of the most dominant malignant tumors in the world. The trends of liver cancer mortality over the past six decades have been tracked in the epidemic region of Qidong, China. Using epidemiological tools, we explore the dynamic changes in age-standardized rates to characterize important aspects of liver cancer etiology and prevention.

METHODS

Mortality data of liver cancer in Qidong from 1958 to 1971 (death retrospective survey) and from 1972 to 2017 (cancer registration) were tabulated for the crude rate (CR), and age-standardized rate and age-birth cohorts. The average annual percentage change was calculated by the Joinpoint Regression Program.

RESULTS

The natural death rate during 1958-2017 decreased from 9‰ to 5.4‰ and then increased to 8‰ as the population aged; cancer mortality rates rose continuously from 57/105 to 240/105. Liver cancer mortality increased from 20/105 to 80/105, and then dropped to less than 52/105 in 2017. Liver cancer deaths in 1972-2017 accounted for 30.53% of all cancers, with a CR of 60.48/105, age-standardized rate China (ASRC) of 34.78/105, and ASRW (world) of 45.71/105. Other key features were the CR for males and females of 91.86/105 and 29.92/105, respectively, with a sex ratio of 3.07:1. Period analysis showed that the ASRs for mortality of the age groups under 54 years old had a significant decreasing trend. Importantly, birth cohort analysis showed that the mortality rate of liver cancer in 40-44, 35-39, 30-34, 25-29, 20-24, 15-19 years cohort decreased considerably, but the rates in 70-74, and 75+ increased.

CONCLUSIONS

The crude mortality rate of liver cancer in Qidong has experienced trends from lower to higher levels, and from continued increase at a high plateau to most recently a gradual decline, and a change greatest in younger people. Many years of comprehensive prevention and intervention measures have influenced the decline of the liver cancer epidemic in this area. The reduction of intake levels of aflatoxin might be one of the most significant factors as evidenced by the dramatic decline of exposure biomarkers in this population during the past three decades.

Translational Application of Circulating DNA in Oncology: Review of the Last Decades Achievements

In recent years, the introduction of new molecular techniques in experimental and clinical settings has allowed researchers and clinicians to propose circulating-tumor DNA (ctDNA) analysis and liquid biopsy as novel promising strategies for the early diagnosis of cancer and for the definition of patients' prognosis. It was widely demonstrated that through the non-invasive analysis of ctDNA, it is possible to identify and characterize the mutational status of tumors while avoiding invasive diagnostic strategies. Although a number of studies on ctDNA in patients' samples significantly contributed to the improvement of oncology practice, some investigations generated conflicting data about the diagnostic and prognostic significance of ctDNA. Hence, to highlight the relevant achievements obtained so far in this field, a clearer description of the current methodologies used, as well as the obtained results, are strongly needed. On these bases, this review discusses the most relevant studies on ctDNA analysis in cancer, as well as the future directions and applications of liquid biopsy. In particular, special attention was paid to the early diagnosis of primary cancer, to the diagnosis of tumors with an unknown primary location, and finally to the prognosis of cancer patients. Furthermore, the current limitations of ctDNA-based approaches and possible strategies to overcome these limitations are presented.

The use of cell free DNA in the diagnosis of HCC

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide and is associated with high mortality. The currently used methods for diagnosing HCC, including imaging modalities and liver biopsy, detect tumors at a relatively advanced stage or are invasive. Non-invasive biomarkers are urgently needed to facilitate screening and early diagnosis of HCC, as well as treatment monitoring and detection of tumor recurrence. Liquid biopsy, the analysis of blood or other body fluids to obtain genetic and epigenetic information, has historically been applied to other types of cancer including breast and prostate cancer. Over the past few decades, liquid biopsy analysis has shed significant insights on genetic and epigenetic aberrations in HCC detectable in peripheral blood. Aberrations in nucleic acids found circulating freely in body fluids or contained within extracellular vesicles such as exosomes or microvesicles show potential clinical utility as non-invasive biomarkers. In this review, we present available literature on cell-free nucleic acids in the diagnosis of HCC.

Liquid biopsy in hepatocellular carcinoma: circulating tumor cells and circulating tumor DNA

Hepatocellular carcinoma (HCC) is one of the most common cancers and a leading cause of death worldwide. Due to latent liver disease, late diagnosis, and nonresponse to systemic treatments, surgical resection and/or biopsy specimens are still generally considered as the gold standard by clinicians for clinical decision-making until now. Since the conventional tissue biopsy is invasive and contains small tissue samples, it is unable to represent tumor heterogeneity or monitor dynamic tumor progression. Therefore, it is imperative to find a new less invasive or noninvasive diagnostic strategy to detect HCC at an early stage and to monitor HCC recurrence. Over the past years, a new diagnostic concept known as “liquid biopsy” has emerged with substantial attention. Liquid biopsy is noninvasive and allows repeated analyses to monitor tumor recurrence, metastasis or treatment responses in real time. With the advanced development of new molecular techniques, HCC circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) detection have achieved interesting and encouraging results. In this review, we focus on the clinical applications of CTCs and ctDNA as key components of liquid biopsy in HCC patients.

Qidong: a crucible for studies on liver cancer etiology and prevention

Qidong (Jiangsu, China) has been of interest to cancer epidemiologists and biologists because, until recently, it was an endemic area for liver cancer, having amongst the highest incidence rates in the world. The establishment of the Qidong Cancer Registry together with the Qidong Liver Cancer Institute in 1972 has charted the patterns of liver cancer incidence and mortality in a stable population throughout a period of enormous economic, social, and environmental changes as well as of improvements in health care delivery. Updated incidence trends in Qidong are described. Notably, the China age-standardized incidence rate for liver cancer has dropped by over 50% in the past several decades. Molecular epidemiologic and genomic deep sequencing studies have affirmed that infection with hepatitis B virus as well as dietary exposure to aflatoxins through contamination of dietary staples such as corn, and to microcystins – blue-green algal toxins found in ditch and pond water – were likely important etiologic factors that account for the high incidence of liver cancer in this region. Public health initiatives to facilitate universal vaccination of newborns against HBV and to improve drinking water sources in this rural area, as well as economic and social mandates serendipitously facilitating dietary diversity, have led to precipitous declines in exposures to these etiologic factors, concomitantly driving substantive declines in the liver cancer incidence seen now in Qidong. In this regard, Qidong serves as a template for the global impact that a package of intervention strategies may exert on cancer burden.

Development of an adverse outcome pathway for chemically induced hepatocellular carcinoma: case study of AFB1, a human carcinogen with a mutagenic mode of action

Adverse outcome pathways (AOPs) are frameworks starting with a molecular initiating event (MIE), followed by key events (KEs) linked by KE relationships (KERs), ultimately resulting in a specific adverse outcome. Relevant data for the pathway and each KE/KER are evaluated to assess biological plausibility, weight-of-evidence, and confidence. We aimed to describe an AOP relevant to chemicals directly inducing mutation in cancer critical gene(s), via the formation of chemical-specific pro-mutagenic DNA adduct(s), as an early critical step in tumor etiology. Such chemicals have mutagenic modes-of-action (MOA) for tumor induction. To assist with developing this AOP, Aflatoxin B1 (AFB1) was selected as a case study because it has a rich database and is considered to have a mutagenic MOA. AFB1 information was used to define specific KEs, KERs, and to inform development of a generic AOP for mutagen-induced hepatocellular carcinoma (HCC). In assessing the AFB1 information, it became clear that existing data are, in fact, not optimal and for some KEs/KERs, the definitive data are not available. In particular, while there is substantial information that AFB1 can induce mutations (based on a number of mutation assays), the definitive evidence - the ability to induce mutation in the cancer critical gene(s) in the tumor target tissue - is not available. Thus, it is necessary to consider the patterns of results in the weight-of-evidence for KEs and KERs. It was important to determine whether there was sufficient evidence that AFB1 can induce the necessary critical mutations early in the carcinogenic process, which was the case.

Differences in somatic mutation landscape of hepatocellular carcinoma in Asian American and European American populations

The incidence rate of hepatocellular carcinoma (HCC) is higher in populations of Asian ancestry than European ancestry (EA). We sought to investigate HCC mutational differences between the two populations, which may reflect differences in the prevalence of etiological factors. We compared HCC somatic mutations in patients of self-reported Asian American and EA from The Cancer Genome Atlas (TCGA), and assessed associations of tumor mutations with established HCC risk factors. Although the average mutation burden was similar, TP53 and RB1 were mutated at a much higher frequency in Asian Americans than in EAs (TP53: 43% vs. 21%; RB1: 19% vs. 2%). Three putative oncogenic genes, including TRPM3, SAGE1, and ADAMTS7, were mutated exclusively in Asians. In addition, VEGF binding pathway, a druggable target by tyrosine kinase inhibitors such as sorafenib, was mutated at a higher frequency among Asians (13% vs. 2%); while the negative regulation of IL17 production, involved in inflammation and autoimmunity, was mutated only in EAs (12% vs. 0). Accounting for HCC risk factors had little impact on any of the mutational differences. In conclusion, we demonstrated here mutational differences in important cancer genes and pathways between Asian and European ancestries. These differences may have implications for the prevention and treatment of HCC.

Prevalence of Aflatoxin-Associated TP53R249S Mutation in Hepatocellular Carcinoma in Hispanics in South Texas

We aimed to determine whether aflatoxin dietary exposure plays a role in the high incidence of hepatocellular carcinoma (HCC) observed among Hispanics in South Texas. We measured TP53R249S somatic mutation, hallmark of aflatoxin etiology in HCC, using droplet digital PCR and RFLP. TP53R249S mutation was detected in 3 of 41 HCC tumors from Hispanics in South Texas (7.3%). We also measured TP53R249S mutation in plasma cell-free DNA (cfDNA) from 218 HCC patients and 96 Hispanic subjects with advanced fibrosis or cirrhosis, from South Texas. The mutation was detected only in Hispanic and Asian HCC patients, and patients harboring TP53R249S mutation were significantly younger and had a shorter overall survival. The mutation was not detected in any Hispanic subject with advanced fibrosis or cirrhosis. Genes involved in cell-cycle control of chromosomal replication and in BRCA1-dependent DNA damage response were enriched in HCCs with TP53R249S mutation. The E2F1 family members, E2F1 and E2F4, were identified as upstream regulators. TP53R249S mutation was detected in 5.7% to 7.3% of Hispanics with HCC in South Texas. This mutation was associated with a younger age and worse prognosis. TP53R249S was however not detected in Hispanics in South Texas with cirrhosis or advanced fibrosis. Aflatoxin exposure may contribute to a small number of HCCs in Hispanics in South Texas, but the detection of TP53R249S mutation in plasma cfDNA is not a promising biomarker of risk assessment for HCC in subjects with cirrhosis or advanced fibrosis in this population. Cancer Prev Res; 11(2); 103-12. ©2017 AACR.

Genome-scale mutational signatures of aflatoxin in cells, mice, and human tumors

Aflatoxin B1 (AFB1) is a mutagen and IARC (International Agency for Research on Cancer) Group 1 carcinogen that causes hepatocellular carcinoma (HCC). Here, we present the first whole-genome data on the mutational signatures of AFB1 exposure from a total of >40,000 mutations in four experimental systems: two different human cell lines, in liver tumors in wild-type mice, and in mice that carried a hepatitis B surface antigen transgene-this to model the multiplicative effects of aflatoxin exposure and hepatitis B in causing HCC. AFB1 mutational signatures from all four experimental systems were remarkably similar. We integrated the experimental mutational signatures with data from newly sequenced HCCs from Qidong County, China, a region of well-studied aflatoxin exposure. This indicated that COSMIC mutational signature 24, previously hypothesized to stem from aflatoxin exposure, indeed likely represents AFB1 exposure, possibly combined with other exposures. Among published somatic mutation data, we found evidence of AFB1 exposure in 0.7% of HCCs treated in North America, 1% of HCCs from Japan, but 16% of HCCs from Hong Kong. Thus, aflatoxin exposure apparently remains a substantial public health issue in some areas. This aspect of our study exemplifies the promise of future widespread resequencing of tumor genomes in providing new insights into the contribution of mutagenic exposures to cancer incidence.

Liquid biopsy in patients with hepatocellular carcinoma: Circulating tumor cells and cell-free nucleic acids

Hepatocellular carcinoma (HCC), with its high incidence and mortality rate, is one of the most common malignant tumors. Despite recent development of a diagnostic and treatment method, the prognosis of HCC remains poor. Therefore, to provide optimal treatment for each patient with HCC, more precise and effective biomarkers are urgently needed which could facilitate a more detailed individualized decision-making during HCC treatment, including the following; risk assessment, early cancer detection, prediction of treatment or prognostic outcome. In the blood of cancer patients, accumulating evidence about circulating tumor cells and cell-free nucleic acids has suggested their potent clinical utilities as novel biomarker. This concept, so-called "liquid biopsy" is widely known as an alternative approach to cancer tissue biopsy. This method might facilitate a more sensitive diagnosis and better decision-making by obtaining genetic and epigenetic aberrations that are closely associated with cancer initiation and progression. In this article, we review recent developments based on the available literature on both circulating tumor cells and cell-free nucleic acids in cancer patients, especially focusing on Hepatocellular carcinoma.

Clinical Significance of Epigenetic Alterations in Human Hepatocellular Carcinoma and Its Association with Genetic Mutations

Accumulation of genetic and epigenetic alterations is a hallmark of cancer genomes, including those in hepatocellular carcinoma (HCC). Particularly, in human HCC, epigenetic changes are more frequently observed than genetic changes in a variety of cancer-related genes, suggesting a potential role for epigenetic alterations during hepatocarcinogenesis. Several environmental factors, such as inflammation, obesity, and steatosis, are reported to affect the epigenetic status in hepatocytes, which could play a role in HCC development. In addition, genetic mutations in histone modulators and chromatin regulators would be critical for the acceleration of epigenetic alteration. It is also possible that major genetic mutations of HCC, such as TP53 and CNTTB1 mutations, are associated with the disturbance of epigenetic integrity. For example, specific TP53 mutations frequently induced by aflatoxin B1 exposure might affect histone modifiers and nucleosome remodelers. Generally, epigenetic alteration is reversible, because of which dysregulation of transcription takes place, without affecting protein structure. Therefore, differentiation therapy is one of the potential approaches for HCC with advanced epigenetic alterations. On the other hand, a tumor carrying an accumulation of genetic mutations would result in many abnormal proteins that could be recognized as non-self and could be targets for immune reactions; thus, immune-checkpoint blockers should be effective for HCCs with genetic hypermutation. Although the emergence of genetic and epigenetic alterations could be linked to each other and there could be some crossover or convergence between these cancer pathways, characterization of the mutation spectrum of genetic and epigenetic alterations could influence future HCC treatment.

Distinct response of the hepatic transcriptome to Aflatoxin B1 induced hepatocellular carcinogenesis and resistance in rats

Aflatoxin is a natural potent carcinogen and a major cause of liver cancer. However, the molecular mechanisms of hepatocellular carcinogenesis remain largely unexplored. In this study, we profiled global gene expression in liver tissues of rats that developed hepatocellular carcinoma (HCC) from aflatoxin B₁ (AFB₁) administration and those that were AFB₁-resistant, as well as rats without AFB₁ exposure as a control. AFB₁ exposure resulted in extensive perturbation in gene expression with different functions in HCC and AFB₁ resistance (AR) samples. The differentially expressed genes (DEGs) in HCC sample were enriched for cell proliferation, cell adhesion and vasculature development that largely contribute to carcinogenesis. Anti-apoptosis genes were up-regulated in HCC sample whereas apoptosis-induction genes were up-regulated in AR sample. AFB₁ exposure also caused extensive alteration in expression level of lncRNAs. Among all the 4511 annotated lncRNAs, half of them were highly expressed only in HCC sample and up-regulated a group of protein-coding genes with cancer-related functions: apoptosis regulation, DNA repair, and cell cycle. Intriguingly, these genes were down-regulated by lncRNAs highly expressed in AR sample. Collectively, apoptosis is the critical biological process for carcinogenesis in response to AFB₁ exposure through changes in expression level of both protein-coding and lncRNA genes.

Liquid Biopsy of Hepatocellular Carcinoma: Circulating Tumor-Derived Biomarkers

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide due to latent liver disease, late diagnosis, and nonresponse to systemic treatments. Till now, surgical and/or biopsy specimens are still generally used as a gold standard by the clinicians for clinical decision-making. However, apart from their invasive characteristics, tumor biopsy only mirrors a single spot of the tumor, failing to reflect current cancer dynamics and progression. Therefore, it is imperative to develop new diagnostic strategies with significant effectiveness and reliability to monitor high-risk populations and detect HCC at an early stage. In the past decade, the potent utilities of “liquid biopsy” have attracted intense concern and were developed to evaluate cancer progression in several clinical trials. “Liquid biopsies” represent a series of noninvasive tests that detect cancer byproducts easily accessible in peripheral blood, mainly including circulating tumor cells (CTCs) and cell-free nucleic acids (cfNAs) that are shed into the blood from the tumor sites. In this review, we focus on the recent developments in the field of “liquid biopsy” as well as the diagnostic and prognostic significance of CTCs and cfNAs in HCC patients.

Identification of HBV-MLL4 Integration and Its Molecular Basis in Chinese Hepatocellular Carcinoma

To gain molecular insights of HBV integration that may contribute to HCC tumorigenesis, we performed whole transcriptome sequencing and whole genome copy number profiling of hepatocellular carcinoma (HCC) samples from 50 Chinese patients. We identified a total of 33 HBV-human integration sites in 16 of 44 HBV-positive HCC tissues, which were enriched in HBV genotype C-infected patients. In addition, significantly recurrent HBV-MLL4 integration (18%; 8/44) was found in this cohort of patients. Using long-range PCR and Sanger sequencing, we comprehensively characterized gDNA and cDNA sequences that encode for the HBV-MLL4 transcripts, and we revealed that HBV integration into MLL4 exons led to much higher mRNA expression of MLL4 than the integration into MLL4 introns due to an alternative splicing mechanism. Moreover, the HBV-MLL4 integration occurred almost exclusively in CTNNB1 and TP53 wild-type patients. The integration was also associated with a distinct gene expression profile. In conclusion, this is the first report on the molecular basis of the MLL4 integration driving MLL4 over-expression. HBV-MLL4 integration occurred frequently in Chinese HCC patients, representing a unique molecular segment for HCC with HBV infection.

Molecular characteristics of Hepatitis B and chronic liver disease in a cohort of HB carriers from Bamako, Mali

BACKGROUND

Hepatitis B (HB) infection is common in Mali. However, there is little information on molecular and biochemical characteristics of HB carriers.

METHODS

A group of 1466 adult volunteers was recruited in the district of Bamako. Confirmed HB carriers were tested for HB viral load by quantitative PCR and HBV was genotyped by sequencing of HBS. Fibrosis and hepatitis activity were measured using the Fibrotest-Actitest. A mutation of TP53 at codon 249 (R249S), specific for exposure to aflatoxin, was detected in cell-free DNA extracted from plasma.

RESULTS

Overall, 276 subjects were HBsAg-positive (18.8%). Among 152 subjects tested for HBV load, 49 (32.2%) had over 10(4) copies/mL and 16 (10.5%) had levels below the limit of detection. The E genotype was found in 91.1% of carriers. Fibrotest scores ≥ F2 were observed in 52 subjects (35.4%). Actitest scores ≥ A2 were detected in 15 subjects (10.2%) and were correlated with Fibrotest scores (p = 0.0006). Among 105 subjects tested, 60% had detectable levels of R249S copies (>40 copies/mL plasma).

CONCLUSION

Chronic HB carriage in adults in Bamako district is well over epidemic threshold. About 1/3 of carriers have moderate to severe liver fibrosis and 60% have detectable aflatoxin-related TP53 R249S mutation. These results support introduction of anti-HB therapies to reduce the progression towards severe liver disease.

A peculiar mutation spectrum emerging from young peruvian patients with hepatocellular carcinoma

Hepatocellular carcinoma usually afflicts individuals in their later years following longstanding liver disease. In Peru, hepatocellular carcinoma exists in a unique clinical presentation, which affects patients around age 25 with a normal, healthy liver. In order to deepen our understanding of the molecular processes ongoing in Peruvian liver tumors, mutation spectrum analysis was carried out on hepatocellular carcinomas from 80 Peruvian patients. Sequencing analysis focused on nine genes typically altered during liver carcinogenesis, i.e. ARID2, AXIN1, BRAF, CTNNB1, NFE2L2, H/K/N-RAS, and TP53. We also assessed the transcription level of factors involved in the control of the alpha-fetoprotein expression and the Hippo signaling pathway that controls contact inhibition in metazoans. The mutation spectrum of Peruvian patients was unique with a major class of alterations represented by Insertions/Deletions. There were no changes at hepatocellular carcinoma-associated mutation hotspots in more than half of the specimens analyzed. Furthermore, our findings support the theory of a consistent collapse in the Hippo axis, as well as an expression of the stemness factor NANOG in high alpha-fetoprotein-expressing hepatocellular carcinomas. These results confirm the specificity of Peruvian hepatocellular carcinoma at the molecular genetic level. The present study emphasizes the necessity to widen cancer research to include historically neglected patients from South America, and more broadly the Global South, where cancer genetics and tumor presentation are divergent from canonical neoplasms.

Hepatitis B virus genetic variation and TP53 R249S mutation in patients with hepatocellular carcinoma in Thailand

Chronic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin B1 (AFB1) are major risk factors for hepatocellular carcinoma (HCC). The aim of this study was to evaluate the role of HBV genetic variation and the R249S mutation of the p53 gene, a marker of AFB1-induced HCC, in Thai patients chronically infected with HBV. Sixty-five patients with and 89 patients without HCC were included. Viral mutations and R249S mutation were characterized by direct sequencing and restriction fragment length polymorphism (RFLP) in serum samples, respectively. The prevalences of T1753C/A/G and A1762T/G1764A mutations in the basal core promotor (BCP) region were significantly higher in the HCC group compared to the non-HCC group. R249S mutation was detected in 6.2% and 3.4% of the HCC and non-HCC groups, respectively, which was not significantly different. By multiple logistic regression analysis, the presence of A1762T/G1764A mutations was independently associated with the risk of HCC in Thai patients.

Association between the P53 codon 72 polymorphism and nasopharyngeal cancer risk

The P53 codon 72 polymorphism has been identified as a critical biomarker in modifying the risk of nasopharyngeal cancer (NPC). Many studies have investigated the association between the polymorphism of P53 codon 72 and NPC risk; however, the findings across the published studies are inconsistent and inconclusive. To acquire a more precise assessment for this association, we conducted an updated meta-analysis. The PubMed, Embase, Web of Science, and Wanfang databases were searched for relevant case-control studies. Totally, seven independent publications with 1,133 cases and 1,678 controls were retrieved. The pooled odds ratio (OR) with corresponding 95% confidence interval (95% CI) was calculated. Increased risk of NPC was observed among individuals carrying the variant allele and genotypes of P53 codon 72 (OR Pro vs. Arg = 1.32, 95% CI 1.18-1.47, P OR < 0.001; OR ProPro vs. ArgArg = 1.90, 95% CI 1.51-2.39, P OR < 0.001; OR ProArg + ProPro vs. ArgArg = 1.33, 95% CI 1.13-1.57, P OR = 0.001; OR ProPro vs. ArgArg + ProArg = 1.65, 95% CI 1.35-2.01, P OR < 0.001). Stratified analyses by ethnicity and source of controls also identified this significant relationship in Asians, Caucasians, and hospital-based case-control studies. There was no publication bias risk in our study. The updated meta-analysis supports the evidence that the polymorphism of P53 codon 72 is a risk factor for the development of NPC among the populations of both Asian and Caucasian.

Association of alpha fetoprotein levels and presence of parasitical blood vessels with response to TACE in patients with advanced liver cancer

AIM: To assess the value of alpha fetoprotein (AFP) levels and presence of parasitical blood vessels in evaluating response to transarterial chemoembolization (TACE) in patients with advanced liver cancer.

METHODS: One hundred and sixty-three patients who were diagnosed with advanced liver cancer by pathology, iconography and tumor molecular biomarker detection and underwent TACE were included in this study. Serum levels of AFP were detected by radioactive enzyme-linked immunoassay. Computer tomography angiography (CTA) was used to detect parasitical angiogenesis.

RESULTS: Of 131 AFP-positive patients before TACE, 82 had decreased AFP after TACE, and the response rate (survival time over one year) was 87.8% (72/82); 13 had increased AFP, and the response rate was 30.8% (4/13); 36 had unchanged AFP, and the response rate was 58.3% (21/36). In contrast, the response rate was 100% (32/32) in 32 AFP-negative patients. The response rate was significantly higher in AFP-negative patients and patients with decreased AFP than in those with increased or unchanged AFP (P < 0.01). Fifty-six patients developed parasitical blood vessels (including 53 AFP-positive and 3 AFP-negative patients). After TACE, the response rate was significantly higher in patients without parasitical blood vessels than in those having parasitical blood vessels (78.5% vs 41.1%, P < 0.05). The percentage of AFP-positive patients having parasitical blood vessels was significantly higher than that of AFP-negative patients having parasitical blood vessels (40.1% vs 9.4%, P < 0.01).

CONCLUSION: Poor treated effects of mid-advanced stage liver cancer patients cured by TACE due to patients contain High serum levels of AFP and presence of parasitic blood vessels are associated with a poor response to TACE in patients with advanced liver cancer. Measurement of AFP concentration and detection of parasitical angiogenesis by CTA may be used to evaluate the response to TACE therapy in patients with advanced liver cancer.

Detection of cancer-specific epigenomic changes in biofluids: powerful tools in biomarker discovery and application

The genetic and epigenetic material originating from tumour that can be found in body fluids of individuals with cancer harbours tumour-specific alterations and represents an attractive target for biomarker discovery. Epigenetic changes (DNA methylation, histone modifications and non-coding RNAs) are present ubiquitously in virtually all types of human malignancies and may appear in early cancer development, and thus they provide particularly attractive markers with broad applications in diagnostics. In addition, because changes in the epigenome may constitute a signature of specific exposure to certain risk factors, they have the potential to serve as highly specific biomarkers for risk assessment. While reliable detection of cancer-specific epigenetic changes has proven to be technically challenging, a substantial progress has been made in developing the methodologies that allow an efficient and sensitive detection of epigenomic changes using the material originating from body fluids. In this review we discuss the application of epigenomics as a tool for biomarker research, with the focus on the analysis of DNA methylation in biofluids.

Exposure to organochlorine pesticides is an independent risk factor of hepatocellular carcinoma: a case-control study

Primary hepatocellular carcinoma (HCC) is highly prevalent in China. Although hepatitis B virus (HBV) and aflatoxin B1 (AFB1) are considered the major risk factors, among the high-risk cohorts only a small fraction develops liver cancer. Therefore, we investigated whether organochlorine pesticide exposure contributed to HCC risk in the Xiamen population. The questionnaire database was built from 346 HCC cases and 961 healthy controls during 2007-2009. The serum levels of α-, β-, γ-, δ-HCH, 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (p,p'-DDT), (1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE), 1,1,1-trichloro-2,2-bis (o-chlorophenyl) ethane and 1,1-dichloro-2,2-bis (p-chlorophenyl) ethane were measured by gas chromatography-tandem mass spectrometer, and statistical analysis was done using SPSS16. Significantly, we observed p,p'-DDT and p,p'-DDE, and at the first time β-HCH displayed quartile dose-dependent HCC risk trends; p,p'-DDT showed positive (i.e., synergistic) interactions with HBV, diabetes mellitus, AFB1 and polyaromatic hydrocarbon (PAH) exposure, but negative (i.e., antagonistic) interaction with heavy drinking; p,p'-DDE had positive interaction with PAH but negative interaction with HBV and p,p'-DDT; and β-HCH positively interacted with p,p'-DDT but negatively interacted with heavy drinking and diabetes. p,p'-DDT, p,p'-DDE and β-HCH were independent HCC risk factors. Because of their synergistic interactions with other factors, the high-level exposure combined with common AFB1 and HBV exposure in the investigated area may greatly enhance the risk of HCC.

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

BACKGROUND

Over 4 billion people worldwide are exposed to dietary aflatoxins, which cause liver cancer (hepatocellular carcinoma, HCC) in humans. However, the population attributable risk (PAR) of aflatoxin-related HCC remains unclear.

METHODS

In our systematic review and meta-analysis of epidemiological studies, summary odds ratios (ORs) of aflatoxin-related HCC with 95% confidence intervals were calculated in HBV+ and HBV- individuals, as well as the general population. We calculated the PAR of aflatoxin-related HCC for each study as well as the combined studies, accounting for HBV status.

RESULTS

Seventeen studies with 1680 HCC cases and 3052 controls were identified from 479 articles. All eligible studies were conducted in China, Taiwan, or sub-Saharan Africa. The PAR of aflatoxin-related HCC was estimated at 17% (14-19%) overall, and higher in HBV+ (21%) than HBV- (8.8%) populations. If the one study that contributed most to heterogeneity in the analysis is excluded, the summarised OR of HCC with 95% CI is 73.0 (36.0-148.3) from the combined effects of aflatoxin and HBV, 11.3 (6.75-18.9) from HBV only and 6.37 (3.74-10.86) from aflatoxin only. The PAR of aflatoxin-related HCC increases to 23% (21-24%). The PAR has decreased over time in certain Taiwanese and Chinese populations.

CONCLUSIONS

In high exposure areas, aflatoxin multiplicatively interacts with HBV to induce HCC; reducing aflatoxin exposure to non-detectable levels could reduce HCC cases in high-risk areas by about 23%. The decreasing PAR of aflatoxin-related HCC reflects the benefits of public health interventions to reduce aflatoxin and HBV.

Exposure to organochlorine pesticides is independent risk factor of hepatocellular carcinoma: a case--control study

Primary hepatocellular carcinoma (HCC) is highly prevalent in China. Although hepatitis B virus (HBV) and aflatoxin B1 (AFB1) are considered the major risk factors, among the high-risk cohorts only a small fraction develops liver cancer. Therefore, we investigated if organochlorine pesticides (OCPs) exposure contributed to HCC risk in the Xiamen population. The questionnaire database was built from 346 HCC cases and 961 healthy controls during 2007-2009. The serum levels of α-, β-, γ-, δ-HCH, p, p'-DDT, p, p'-DDE, o, p'-DDT and p, p'-DDD were measured by gas chromatography-tandem mass spectrometer and statistical analysis was done using SPSS16. Significantly, we observed p, p'-DDT, p, p'-DDE, and at first time β-HCH displayed quartile dose-dependent HCC risk trends; p, p'-DDT showed positive (i.e., synergistic) interactions with HBV, diabetes mellitus, AFB1 and polycyclic aromatic hydrocarbon (PAH) exposure, but negative (i.e., antagonistic) interaction with heavy drinking; p, p'-DDE had positive interaction with PAH but negative interaction with HBV and p, p'-DDT; and β-HCH was positively interacted with p, p'-DDT but negatively interacted with heavy drinking and diabetes. p, p'-DDT, p, p'-DDE and β-HCH were independent HCC risk factors. Because of their synergistic interactions with other factors, the high level exposure combined with common AFB1 and HBV exposure in the investigated area may greatly enhance the risk of HCC.

Seasonal variation in TP53 R249S-mutated serum DNA with aflatoxin exposure and hepatitis B virus infection

BACKGROUND

Chronic hepatitis B virus (HBV) infection and dietary aflatoxin B1 (AFB1) exposure are etiological factors for hepatocellular carcinoma (HCC) in countries with hot, humid climates. HCC often harbors a TP53 (tumor protein p53) mutation at codon 249 (R249S). In chronic carriers, 1762T/1764A mutations in the HBV X gene are associated with increased HCC risk. Both mutations have been detected in circulating cell-free DNA (CFDNA) from asymptomatic HBV carriers.

OBJECTIVE

We evaluated seasonal variation in R249S and HBV in relation to AFB1 exposure.

METHODS

R249S was quantitated by mass spectrometry in CFDNA in a cross-sectional survey of 473 asymptomatic subjects (237 HBV carriers and 236 noncarriers) recruited in three villages in the Gambia over a 10-month period. 1762T/1764A HBV mutations were detected by quantitative polymerase chain reaction. In addition, the HBV S gene was sequenced in 99 subjects positive for HBV surface antigen (HBsAg).

RESULTS

We observed a seasonal variation of serum R249S levels. Positivity for R249S and average concentration were significantly higher in HBsAg-positive subjects surveyed during April-July (61%; 5,690 ± 11,300 R249S copies/mL serum) than in those surveyed October-March [32% and 480 ± 1,030 copies/mL serum (odds ratio = 3.59; 95% confidence interval: 2.05, 6.30; p < 0.001)]. Positivity for HBV e antigen (HBeAg) (a marker of HBV replication) and viral DNA load also varied seasonally, with 15-30% of subjects surveyed between April and June HBeAg positive, compared with < 10% surveyed during other months. We detected 1762T/1764A mutations in 8% of carriers, half of whom were positive for R249S. We found HBV genotype E in 95 of 99 HBsAg-positive subjects.

CONCLUSION

R249S is detectable in CFDNA of asymptomatic subjects. Evidence of temporal and quantitative variations suggests an interaction among AFB1 exposure, HBV positivity, and replication on TP53 mutation formation or persistence.

Mass spectrometric based analysis, characterization and applications of circulating cell free DNA isolated from human body fluids

In the past decade, cell free DNA, or circulating cell free DNA, or cell free circulating DNA, isolated from body fluids such as plasma/serum/urine has emerged as an important tool for clinical diagnostics. The molecular biology of circulating cell free DNA is poorly understood but there is currently an increased effort to understand the origin, mechanism of its circulation, and sensitive characterization for the development of diagnostic applications. There has been considerable progress towards these goals using real time polymerase chain reaction technique (rt-PCR). More recently, new attempts to incorporate mass spectrometric techniques to develop accurate and highly sensitive high-throughput clinical diagnostic tests have been reported. This review focuses on the methods to isolate circulating cell free DNA from body fluids, their quantitative analysis and mass spectrometry based characterization in evolving applications as prenatal and cancer diagnostic tools.

Liver cancer epidemic in China: past, present and future

Primary liver cancer is the second most common malignancy, and currently results in 360,000 incident cases, and 350,000 deaths a year in China. For the past four decades, three national surveys on cancer mortality during the periods of 1973-1975, 1990-1992, and 2004-2005 have made it possible to estimate China's past and present liver cancer epidemic. The mortality rates of liver cancer were 17.6 and 7.3 per 100,000 for males and females in 1973-1975, 29.0 and 11.2 per 100,000 in 1990-1992, and 37.55 and 14.45 per 100,000 in 2004-2005, respectively. Recent monitoring from some regional cancer registries, which cover 5.7% of the total population in China, has revealed the distribution, disparities and trends of liver cancer in rural and urban areas. HBV and aflatoxins have been identified as major causal factors, that act individually and synergistically of liver cancer in the etiology. Other agents such as HCV, genetic susceptibility or genetic polymorphisms may also play important roles in the development of liver cancer. Great effort aimed at primary and Secondary prevention of this cancer, such as universal hepatitis B vaccination in children, chemoprevention in selected population, and early detection in at-risk population, has been undertaken. These strategies might be further emphasized in the future for the effective prevention of liver cancer in China.

Selected technologies for measuring acquired genetic damage in humans

Technical advances have improved the capacity to detect and quantify genetic variants, providing novel methods for the detection of rare mutations and for better understanding the underlying environmental factors and biological mechanisms contributing to mutagenesis. The polymerase chain reaction (PCR) has revolutionized genetic testing and remains central to many of these new techniques for mutation detection. Millions of genetic variations have been discovered across the genome. These variations include germline mutations and polymorphisms, which are inherited in a Mendelian manner and present in all cells, as well as acquired, somatic mutations that differ widely by type and size [from single-base mutations to whole chromosome rearrangements, and including submicroscopic copy number variations (CNVs)]. This review focuses on current methods for assessing acquired somatic mutations in the genome, and it examines their application in molecular epidemiology and sensitive detection and analysis of disease. Although older technologies have been exploited for detecting acquired mutations in cancer and other disease, the high-throughput and high-sensitivity offered by next-generation sequencing (NGS) systems are transforming the discovery of disease-associated acquired mutations by enabling comparative whole-genome sequencing of diseased and healthy tissues from the same individual. Emerging microfluidic technologies are beginning to facilitate single-cell genetic analysis of target variable regions for investigating cell heterogeneity within tumors as well as preclinical detection of disease. The technologies discussed in this review will significantly expand our knowledge of acquired genetic mutations and causative mechanisms.

p53 Plays an important role in cell fate determination after exposure to microcystin-LR

BACKGROUND

Microcystin-LR, a cyclic heptapeptide, possesses the ability to inhibit the serine/threonine protein phosphatases PP1 and PP2A and, consequently, exhibits acute hepatocytotoxicity. Moreover, microcystin-LR induces cellular proliferation, resulting in tumor-promoting activity in hepatocytes. However, mechanisms that regulate the balance between cell death and proliferation after microcystin-LR treatment remain unclear.

OBJECTIVE

We examined the contribution of the transcription factor p53, as well as that of the hepatic uptake transporter for microcystin-LR, organic anion transporting polypeptide 1B3 (OATP1B3), to the cellular response to microcystin-LR exposure.

METHODS

We analyzed intracellular signaling responses to microcystin-LR by immunoblotting and real-time reverse-transcriptase polymerase chain reaction techniques using HEK293 human embryonic kidney cells stably transfected with SLCO1B3 (HEK293-OATP1B3). In addition, we analyzed the effect of attenuation of p53 function, via the p53 inhibitor pifithrin-alpha, and knockdown of p53 mRNA on the cytotoxicity of microcystin-LR using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

Microcystin-LR induced the phosphorylation and accumulation of p53 in HEK293-OATP1B3 cells, which resulted in up-regulation of the expression of p53 transcript targets, including p21 and seven in absentia homolog 1 (siah-1). In addition, microcystin-LR activated Akt signaling through the phosphorylation of Akt and glycogen synthase kinase 3beta. Although Akt signaling was activated, the accumulation of p53 led cells to apoptosis after treatment with 50 nM microcystin-LR for 24 hr. Both pharmacological inhibition of transcription factor activity of p53 by pifithrin-alpha and knockdown of p53 with small hairpin RNA attenuated the susceptibility of HEK293-OATP1B3 cells to microcystin-LR.

CONCLUSIONS

This study demonstrates the importance of p53 in the regulation of cell fate after exposure to microcystin-LR. Our results suggest that, under conditions of p53 inactivation (including p53 mutation), chronic exposure to low doses of microcystin-LR may lead to cell proliferation through activation of Akt signaling. Results of this study may contribute to the development of chemoprevention and chemotherapeutic approaches to microcystin-LR poisoning.

Detection and characterization of liver lesions using gadoxetic acid as a tissue-specific contrast agent

The value of cross-sectional liver imaging is evaluated by the accuracy, sensitivity, and specificity of the specific imaging technique. Magnetic resonance imaging (MRI) has become a key technique for the characterization and detection of focal and diffuse liver disease. More recently, gadoxetic acid, the hepatocyte-specific MR contrast agent, was clinically approved and introduced in many countries. Gadoxetic acid may be considered a "molecular imaging" probe because the compound is actively taken into hepatocytes via the ATP-dependent organic anion transport system in the plasma membrane for the hepatic uptake. The transport of gadoxetic acid from the cytoplasm to the bile is mainly determined by the capacity of the transport protein glutathione-S-transferase. Gadoxetic acid enhances hepatocyte-containing lesions and improves detection of lesions devoid of normal hepatocytes, such as metastases. Innovative rapid MR acquisition techniques with near isotropic 3D pulse sequences with fat saturation parallel the technical progress made by multidetector computed tomography combined with an impressive improvement in tumor-liver contrast when used for gadoxetic acid-enhanced MRI. The purpose of this review is to provide an overview of the development, clinical testing, and applications of this novel MR contrast agent.

Cell-free DNA in the blood as a solid tumor biomarker--a critical appraisal of the literature

Circulating cell-free DNA (cfDNA) has been suggested as a cancer biomarker. Several studies assessed the usefulness of quantitative and qualitative tumor-specific alterations of cfDNA, such as DNA strand integrity, frequency of mutations, abnormalities of microsatellites, and methylation of genes, as diagnostic, prognostic, and monitoring markers in cancer patients. Most of the papers that could be evaluated in this review resulted in a positive conclusion. However, methodical diversity without the traceability of data and differently designed and often underpowered studies resulted in divergent results between studies. In addition, the limited diagnostic sensitivity and specificity of cfDNA alterations temper the effusive hope of novel tumor markers, raising similar issues as those for other tumor markers. To validate the actual clinical validity of various cfDNA alterations as potential cancer biomarkers in practice for individual tumor types, the main problems of the observed uncertainties must be considered in future studies. These include methodical harmonization concerning sample collection, processing, and analysis with the traceability of measurement results as well as the realization of well-designed prospective studies based on power analysis and sample size calculations.

Effects of the TP53 p.R249S mutant on proliferation and clonogenic properties in human hepatocellular carcinoma cell lines: interaction with hepatitis B virus X protein

Aflatoxin B(1) (AFB(1)) is a risk factor for hepatocellular carcinoma (HCC) in many low-resource countries. Although its metabolites bind at several positions in TP53, a mutation at codon 249 (AGG to AGT, arginine to serine, p.R249S) accounts for 90% of TP53 mutations in AFB(1)-related HCC. This specificity suggests that p.R249S confers a selective advantage during hepatocarcinogenesis. Using HCC cell lines, we show that p.R249S has lost the capacity to bind to p53 response elements and to transactivate p53 target genes. In p53-null Hep3B cells, stable transfection of p.R249S or of another mutant, p.R248Q, did not induce significant changes in cell proliferation and survival after cytotoxic stress. In contrast, in a cell line that constitutively expresses both p.R249S and the hepatitis B virus antigen HBx (PLC/PRF/5), silencing of either p.R249S or HBx by RNA interference slowed down proliferation, with no additive effects when both factors were silenced. Furthermore, the two proteins appear to form a complex. In human HCC samples, mutation at codon 249 did not correlate with p.R249S protein accumulation or HBx truncation status. We suggest that p.R249S may contribute to hepatocarcinogenesis through interaction with HBx, conferring a subtle growth advantage at early steps of the transformation process, but that this interaction is not required for progression to advanced HCC.

Global burden of aflatoxin-induced hepatocellular carcinoma: a risk assessment

BACKGROUND

Hepatocellular carcinoma (HCC), or liver cancer, is the third leading cause of cancer deaths worldwide, with prevalence 16-32 times higher in developing countries than in developed countries. Aflatoxin, a contaminant produced by the fungi Aspergillus flavus and Aspergillus parasiticus in maize and nuts, is a known human liver carcinogen.

OBJECTIVES

We sought to determine the global burden of HCC attributable to aflatoxin exposure.

METHODS

We conducted a quantitative cancer risk assessment, for which we collected global data on food-borne aflatoxin levels, consumption of aflatoxin-contaminated foods, and hepatitis B virus (HBV) prevalence. We calculated the cancer potency of aflatoxin for HBV-postive and HBV-negative individuals, as well as the uncertainty in all variables, to estimate the global burden of aflatoxin-related HCC.

RESULTS

Of the 550,000-600,000 new HCC cases worldwide each year, about 25,200-155,000 may be attributable to aflatoxin exposure. Most cases occur in sub-Saharan Africa, Southeast Asia, and China where populations suffer from both high HBV prevalence and largely uncontrolled aflatoxin exposure in food.

CONCLUSIONS

Aflatoxin may play a causative role in 4.6-28.2% of all global HCC cases.