P53 mutations in hepatocellular carcinoma patients in Egypt

A Review of Incidence and Related Risk Factors in the Development of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a primary liver malignancy, ranking as the seventh most common cancer globally and the second leading cause of deaths due to cancer. This review examines the incidence of HCC, its associated risk factors, and constantly changing global trends. Incidence has been noted to be varying worldwide, particularly due to environmental and infectious risk factors. Chronic hepatitis B (HBV) and C (HCV) virus infections, alcohol abuse, aflatoxin exposure, diabetes, obesity, and tobacco consumption are some of the leading risk factors noted. Eastern Asia and sub-Saharan Africa were noted to have the highest disease burden for HCC, with China representing a considerably large majority. On the contrary, the United States reports a lower HCC incidence overall due to improved vaccination programs against HBV; however, with a rising incidence of prominent risk factor in non-alcoholic fatty liver disease (NAFLD), the trend may very well change. Gender disparities were noted to be evident with men experiencing higher rates of HCC compared to women, which may be due to various environmental and biological factors, including alcohol intake, smoking, and androgen hormone levels. Currently, efforts to reduce the overall incidence of HCC include universal HBV vaccinations, antiviral therapies, aflatoxin prevention measures, genetic screening for hereditary hemochromatosis, and early ultrasound evaluation in patients with liver cirrhosis. Understanding these evolving trends and risk factors is essential in combating the rising HCC incidence, especially in Western countries, where risk factors, such as obesity, diabetes, and metabolic disorders, are on the rise.

Genomics in Egypt: Current Status and Future Aspects

Egypt is the third most densely inhabited African country. Due to the economic burden and healthcare costs of overpopulation, genomic and genetic testing is a huge challenge. However, in the era of precision medicine, Egypt is taking a shift in approach from “one-size-fits all” to more personalized healthcare via advancing the practice of medical genetics and genomics across the country. This shift necessitates concrete knowledge of the Egyptian genome and related diseases to direct effective preventive, diagnostic and counseling services of prevalent genetic diseases in Egypt. Understanding disease molecular mechanisms will enhance the capacity for personalized interventions. From this perspective, we highlight research efforts and available services for rare genetic diseases, communicable diseases including the coronavirus 2019 disease (COVID19), and cancer. The current state of genetic services in Egypt including availability and access to genetic services is described. Drivers for applying genomics in Egypt are illustrated with a SWOT analysis of the current genetic/genomic services. Barriers to genetic service development in Egypt, whether economic, geographic, cultural or educational are discussed as well. The sensitive topic of communicating genomic results and its ethical considerations is also tackled. To understand disease pathogenesis, much can be gained through the advancement and integration of genomic technologies via clinical applications and research efforts in Egypt. Three main pillars of multidisciplinary collaboration for advancing genomics in Egypt are envisaged: resources, infrastructure and training. Finally, we highlight the recent national plan to establish a genome center that will aim to prepare a map of the Egyptian human genome to discover and accurately determine the genetic characteristics of various diseases. The Reference Genome Project for Egyptians and Ancient Egyptians will initialize a new genomics era in Egypt. We propose a multidisciplinary governance system in Egypt to support genomic medicine research efforts and integrate into the healthcare system whilst ensuring ethical conduct of data.

A Review of Cancer Genetics and Genomics Studies in Africa

Cancer is the second leading cause of death globally and is projected to overtake infectious disease as the leading cause of mortality in Africa within the next two decades. Cancer is a group of genomic diseases that presents with intra- and inter-population unique phenotypes, with Black populations having the burden of morbidity and mortality for most types. At large, the prevention and treatment of cancers have been propelled by the understanding of the genetic make-up of the disease of mostly non-African populations. By the same token, there is a wide knowledge gap in understanding the underlying genetic causes of, and genomic alterations associated with, cancer among black Africans. Accordingly, we performed a review of the literature to survey existing studies on cancer genetics/genomics and curated findings pertaining to publications across multiple cancer types conducted on African populations. We used PubMed MeSH terms to retrieve the relevant publications from 1990 to December 2019. The metadata of these publications were extracted using R text mining packages: RISmed and Pubmed.mineR. The data showed that only 0.329% of cancer publications globally were on Africa, and only 0.016% were on cancer genetics/genomics from Africa. Although the most prevalent cancers in Africa are cancers of the breast, cervix, uterus, and prostate, publications representing breast, colorectal, liver, and blood cancers were the most frequent in our review. The most frequently reported cancer genes were BRCA1, BRCA2, and TP53. Next, the genes reported in the reviewed publications’ abstracts were extracted and annotated into three gene ontology classes. Genes in the cellular component class were mostly associated with cell part and organelle part, while those in biological process and molecular function classes were mainly associated with cell process, biological regulation, and binding, and catalytic activity, respectively. Overall, this review highlights the paucity of research on cancer genomics on African populations, identified gaps, and discussed the need for concerted efforts to encourage more research on cancer genomics in Africa.

Relative Importance of Hepatitis B and C Viruses in Hepatocellular Carcinoma in EMRO Countries and the Middle East: A Systematic Review

CONTEXT

Hepatocellular carcinoma (HCC) is the second most common cancer-related death worldwide. Although many factors including dietary aflatoxin B1 (AFB1) and alcoholic and non-alcoholic fatty liver diseases can lead to HCC, globally most HCC cases are due to hepatitis B virus (HBV) and hepatitis C virus (HCV). Considering the importance of these viral factors in most HCC cases and relative lack of literature from eastern Mediterranean region office of world health organization (EMRO) countries and the Middle East, we decided to perform this systematic review to find distribution of viral etiology of HCC in these regions.

EVIDENCE ACQUISITION

In this systemic review, we included all studies from 1 January 1989 to 1 September 2015 with at least 20 samples that measured HBV surface antigen (HBsAg) and antibodies to HCV (anti-HCV). The authors searched MEDLINE, Embase, Popline, Web of Science and WHO indexed databases. We searched the following MeSH terms; hepatocellular carcinoma, hepatitis B virus and hepatitis C virus or hepacvirus. Only studies using second- and third-generation HCV assays were included. Only articles studying HCC patients from EMRO countries and the Middle East were analyzed. Duplicate results that reported the same cases more than once were found and omitted. Studies in English and Farsi were reviewed. If the study was eligible, we recorded the following data; the first author, publication year and journal, study population and number and percentage of patients with different serologic statuses.

RESULTS

We found 44 studies from 12 countries in EMRO and the Middle East. HCC cases from Iran, Lebanon, Turkey and Yemen were mainly due to HBV, while those of North African nations (Egypt, Tunisia, Morocco, Algeria and Somalia) in addition to Saudi Arabia and Pakistan were mostly HCV related. Sudan showed a high seronegativity and HBV infection in its HCC cases. Unfortunately, some countries from EMRO and the Middle East did not have eligible studies.

CONCLUSIONS

HBV and HCV are important culprits of HCC in EMRO countries and the Middle East and different nations need different strategies to tackle them accordingly. Countries with high rates of HBV such as Turkey should continue their HBV vaccination and also increase sanitation. Nations with high HCV rates such as Egypt should maintain their blood product monitoring in addition to increased sanitation, especially regarding injection drug users (IDU).

Prevalence of aflatoxin induced p53 mutation at codon 249 (R249s) in hepatocellular carcinoma patients with and without hepatitis B surface antigen (HBsAg)

BACKGROUND

A missense mutation in exon 7 (R249S) of the p53 tumor suppressor gene is characteristic of aflatoxin B1 (AFB1) exposure. AFB1 is believed to have a synergistic effect on hepatitis virus B (HBV) carcinogenesis. However, results of studies comparing R249S prevalence among patients are conflicting. The aim of this study was to determine the prevalence of the R249S mutation in hepatocellular carcinoma (HCC) patients with or without positive HBsAg.

MATERIALS AND METHODS

Paraffin embedded liver tissues were obtained from 124 HCC patients who underwent liver resection and liver biopsy in King Chulalongkorn Memorial Hospital. Restriction fragment length polymorphism (RFLP) was utilized to detect the R249S mutation. Positive results were confirmed by direct sequencing.

RESULTS

Sixty four (52%) patients were positive for HBsAg and 18 (15%) were anti-HCV positive. 12 specimens tested positive by RFLP. Ten HCC patients (8.1%) were confirmed to be R249S positive by Sanger sequencing (AGG to AGT). Out of these 10, six were HBsAg positive, and out of the remaining 4, two were anti-HCV positive. The R249S prevalence among HCC patients with positive HBsAg was 9.4% compared to 6.7% for HBsAg negative samples. Patients with the R249S mutation were younger (55±10 vs 60±13 year-old) and tended to have a more advanced Edmonson-Steiner grade of HCC, although differences did not reach statistical significance.

CONCLUSIONS

Our study shows moderate prevalence of aflatoxin B1-related p53 mutation (R249S) in HCC with or without HBsAg. HBsAg positive status was not associated with R249S prevalence.

Knowledge and perceptions of hepatitis C infection and pesticides use in two rural villages in Egypt

Background

Hepatocellular carcinoma (HCC), one of the most fatal types of malignancy, is increasing worldwide, and particularly in Egypt where there is a confluence of its contributing factors, including high prevalence of hepatitis C virus (HCV) infection, widespread use of pesticides, and diets that are contaminated by aflatoxin B1 (AFB1) in rural areas. We investigated knowledge, attitudes, and prevention practices related to HCV infection and pesticides use in rural Egypt, where over half of the population resides and agriculture is the predominant occupation.

Methods

From two rural villages we recruited 67 residents aged 18–80 years, who completed a 40-item survey that included questions about demographics, knowledge of and protective measures relevant to pesticides use in the home and in agriculture, awareness and perceptions of HCV infection and its treatment and prevention.

Results

Among the 67 study participants, gender distribution was equal, the mean age was 47.2, and one third never attended school. More than 50% reported using pesticides at home, but fewer reported having some knowledge about its health effects. Twelve participants were agricultural workers, and 11 of them applied pesticides in the field and knew about their toxicity; however only one person was correctly using the appropriate protective equipment. Among all the participants, 52 did not know what causes HCV infection, and 42 of those who knew it was a virus mentioned incorrect modes of transmission; and 30 did not know the disease manifestations.

Conclusion

In rural Egypt, there is a significant lack of knowledge of HCV infection and its transmission mode and limited use of protective measures against pesticides despite familiarity with these chemicals.

Hepatitis C virus infection in the Maghreb region

Hepatitis C is a global health problem with a worldwide prevalence of about 3% (around 170 million people). Hepatitis C virus (HCV) is major concern in the Maghreb countries, Algeria, Libya, Mauritania, Morocco, and Tunisia, but no detailed description of its epidemiology in the region is available. In the present review, a systematic search was undertaken covering HCV data available in peer-reviewed databases as well as institutional reports and regional conference meeting abstracts from the Maghreb countries. Reports written in English and French were included in this analysis. Estimates of national and regional prevalence of HCV infection (based on anti-HCV antibody) and of the size of patient populations were performed. In addition, the molecular features of the circulating viral strains in the region are discussed. A substantial proportion, 1.2-1.9% of the Maghreb inhabitants, have anti-HCV antibodies. Genotype 1b predominates among viral strains in all countries except in Libya, where genotype 4 is dominant as in neighboring Egypt. This epidemiological situation is of significant concern, and requires urgent, broad, and active intervention for the prevention and control of HCV. More specifically, the application of state-of-the-art hygiene procedures and rigorous controls in medical disciplines such as hemodialysis, transfusion, endoscopic procedures, and dentistry is necessary to reduce significantly the number of new infections in the region.

Global geographical overlap of aflatoxin and hepatitis C: controlling risk factors for liver cancer worldwide

About 85% of hepatocellular carcinoma (HCC, liver cancer) cases occur in low-income countries, where the risk factors of dietary aflatoxin exposure and chronic hepatitis B and C (HBV and HCV) viral infection are common. While studies have shown synergism between aflatoxin and HBV in causing HCC, much less is known about whether aflatoxin and HCV synergise similarly. From an exposure perspective, it was examined whether there is a geographical overlap in populations worldwide exposed to high dietary aflatoxin levels and with high HCV prevalence. While HCV is one of the most important risk factors for HCC in high-income nations (where aflatoxin exposure is low), it is found that HCV prevalence is much higher in Africa and Asia, where aflatoxin exposure is also high. However, within a given world region, there are some inconsistencies regarding exposure and cancer risk. Therefore, there is a need to control risk factors such as aflatoxin and hepatitis viruses in a cost-effective manner to prevent global HCC, while continuing to evaluate biological mechanisms by which these risk factors interact to increase HCC risk.

MDM2 SNP309T>G polymorphism with hepatocellular carcinoma risk: a meta-analysis

BACKGROUND AND AIMS

The murine double minute 2 (MDM2) gene encodes a negative regulator of the tumor protein p53. A single nucleotide polymorphism (SNP) in MDM2 promoter, SNP309 T>G, has been reported to alter MDM2 protein expression and accelerate tumor formation in humans. Studies investigating the association between the polymorphism and human hepatocellular carcinoma (HCC) risk reported conflicting results. We performed a meta-analysis to explore the association of this polymorphism and HCC risk.

METHODS

All eligible studies published were searched for in PubMed. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were assessed for the association using fixed- and random-effects models.

RESULTS

We identified five case-control studies including 738 cases and 1014 controls for the present meta-analysis. In studies with limited data, we detected significant associations for all genetic models in the overall analysis (OR = 2.51, 95% CI = 1.88-3.36 for GG vs. TT, p <0.001, P(het) = 0.666; OR = 1.71, 95% CI = 1.35-2.18 for TG vs. TT, p <0.001, P(het) = 0.925; OR = 1.94, 95% CI = 1.54-2.43 for dominant model TG + GG vs. TT, p <0.001, P(het) = 0.772; OR = 1.74, 95% CI = 1.39-2.20 for recessive model GG vs. TT + TG, p <0.001, P(het) = 0.656). Moreover, in the subgroup analysis based on Hardy-Weinberg equilibrium (HWE) in controls, sample size, and ethnicity, significant associations were observed in most genetic models.

CONCLUSIONS

This meta-analysis suggests that the MDM2 309 G allele probably acts as an important HCC risk factor. To further confirm our findings, well-designed studies with large sample sizes and representing different ethnicities are required.

Epidemiologic risk factors of hepatocellular carcinoma in a rural region of Egypt

BACKGROUND

Hepatocellular carcinoma (HCC) is a major health problem worldwide, including Egypt. In the recent past, HCC has become the second most prevalent cancer among men in Egypt. Since HCC has not been well studied in the rural population of Egypt, this case-control study was conducted to investigate the epidemiologic risk factors of HCC in the predominantly rural region of Gharbiah, Egypt.

METHODS

A total of 150 cases and 150 controls matched to cases on age (±5 years) and sex were recruited from the Gharbiah Cancer Society and Tanta Cancer Center. Exposure data were collected by an interviewer-administered standardized questionnaire about epidemiologic, occupational, medical and family history of HCC. Conditional logistic regression was utilized to calculate unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CI). The effect modification of HCC risk between viral infection and environmental risk factors was also assessed.

RESULTS

Being an industrial worker was an independent risk for developing HCC (OR 3.54, 95% CI 1.18, 10.63) after adjusting for viral infection, schistosomiasis and tobacco smoking. High relative risk of HCC was observed among HCV-infected individuals who were farmers (OR 9.60, 95% CI 3.72, 24.76), industrial workers (OR 12.90, 95% CI 4.33, 38.43) or active smokers (OR 5.95, 95% CI 2.20, 16.08).

CONCLUSION

Occupational exposure may play an important role in the development of HCC. Farming, industrial exposures and cigarette smoking may increase the risk of HCC among HCV-seropositive individuals. Future research focusing on mechanisms of occupational exposures among HCV patients in this population is needed.

Hepatocellular Carcinoma: Tumorigenesis and Prediction Markers

Hepatocellular carcinoma (HCC) is one of the most common malignancies. Although many advances have been made in the clinical study of HCC, the prognosis remains poor. Despite the discoveries in cancer biology in respect with physiological and pathological factors in relation to prognosis, HCC remains still a fatal disease due to late diagnosis. For improving the outcomes of patients with HCC, it is important to identify the factors predisposing to patient death. In recent years, based on cellular and molecular biology techniques, many tumor markers related to invasion, metastasis, recurrence and survival have been explored. However, routine biomarkers for the prediction of HCC evolution and prognosis are available in small number and less specific. These reviews focus on the recent advances in HCC tumorigenesis, revealing those biomarkers with prognosis significance or can be used for early detection.

MDM2 SNP309T>G polymorphism and risk of hepatocellular carcinoma: a case-control analysis in a Moroccan population

BACKGROUND

The Murine double minute 2 (MDM2) gene encodes a negative regulator of the p53 tumor suppressor protein. A single nucleotide polymorphism (SNP) in the MDM2 promoter (a T to G exchange at nucleotide 309) has been reported to produce accelerated tumor formation. The aim of this study was to investigate whether this functional SNP is associated with an enhanced risk of liver tumorigenesis in Moroccan patients.

METHODS

The study consisted in the comparison of 96 hepatocellular carcinomas (HCC) cases and 222 controls without HCC matched for age, gender and ethnicity. PCR-RFLP and sequencing methods were used to determine the genotype at the MDM2 SNP309T>G locus.

RESULTS

Overall, our results indicate that the GG genotype of SNP309 is significantly associated with an increased risk of HCC (odds ratio, OR=2.60, 95% CI, 1.08-6.28). Interestingly, despite a wide range of confidence interval, there is a trend associating the GG genotype with a high risk of HCC in males (OR=3.31; 95% CI, 0.93-11.82) and in HCV-infected patients (OR=3.7; 95% CI, 0.82-16.45). By contrast, no association between age at diagnosis and MDM2 SNP309 genotypes was observed in HCC patients (P=0.610).

CONCLUSION

Our findings suggest that the MDM2 309T>G polymorphism is an important modulator of hepatocellular carcinoma development in Moroccan patients.

Epidemiology of hepatitis viruses among hepatocellular carcinoma cases and healthy people in Egypt: a systematic review and meta-analysis

Liver cancers are strongly linked to hepatitis B virus (HBV) and hepatitis C virus (HCV). Egypt has the highest prevalence of HCV worldwide and has rising rates of hepatocellular carcinoma (HCC). Egypt's unique nature of liver disease presents questions regarding the distribution of HBV and HCV in the etiology of HCC. Accordingly, a systematic search of MEDLINE, ISI Web of Science, ScienceDirect and World Health Organisation databases was undertaken for relevant articles regarding HBV and HCV prevalence in Egypt among healthy populations and HCC cases. We calculated weighted mean prevalences for HBV and HCV among the populations of interest and examined differences in prevalence by descriptive features, including age, year and geographic region. Prevalences for HBV and HCV were 6.7% and 13.9% among healthy populations, and 25.9% and 78.5% among HCC cases. Adults had higher prevalences of both infections (Adult HBV=8.0%, Child HBV=1.6%; Adult HCV=15.7%, Child HCV=4.0%). Geographically, HBV was higher in the south, whereas HCV was greater in the north (North HBV=4.6%, South HBV=11.7%; North HCV=15.8%, South HCV=6.7%). Among HCC cases, HBV significantly decreased over time (p=0.001) while HCV did not, suggesting a shift in the relative influences of these viruses in HCC etiology in Egypt. Our results highlight large amounts of heterogeneity among the epidemiological factors associated with liver disease in Egypt and underscore the necessity of an integrated strategy for the successful prevention of viral hepatitis infections and chronic liver disease.

The Pro variant of the p53 codon 72 polymorphism is associated with hepatocellular carcinoma in Moroccan population

AIM

Codon 72 polymorphism of the p53 gene has been implicated in cancer risk, and it has been suggested that it may have an impact on the clinical outcome of the disease. Our objective was to evaluate the association between p53 polymorphism at codon 72 and hepatocellular carcinoma (HCC) in the Moroccan population.

METHODS

Genomic DNA was extracted from peripheral blood cells of 96 patients with HCC and 222 controls without HCC matched for age, gender and ethnicity. Codon 72 polymorphism of p53 was identified by PCR-restriction fragment length polymorphism, confirmed by sequencing.

RESULTS

Patients with HCC had higher frequencies of Pro/Pro (13.5% vs. 6.3%, P < 0.02) than controls and consequently a 2.3-fold increased risk of liver cancer development (odds ratio [OR], 2.304; 95% confidence interval [CI], 1.014-5.234). In addition, we found a significant association between the p53Arg72Pro polymorphism and the female gender in HCC. Men with Pro/Pro genotype had a 1.57-fold increased risk for HCC, whereas the corresponding genotype in women had a 4.4-fold increased risk of HCC (OR, 4.4; 95% CI, 1.18-16.42). No correlation between the polymorphism and HCC risk was found when comparing the hepatitis C virus (HCV)-positive cases to HCV-positive controls. However, HCV-negative subjects and Pro/Pro genotype had a 3.31-fold increased risk for HCC.

CONCLUSION

These results provide evidence that p53 polymorphism at codon 72 is a modifier of hepatocarcinogenesis, especially in women and HCV-negative subjects.

Genomic stability prevails in North-African hepatocellular carcinomas

The molecular pathogenesis of hepatocellular carcinoma, a tumour characterized by a vast clinical heterogeneity, remains unexplored outside Europe and Eastern Asia. We analysed by direct sequencing or loss of heterozygosity assay, the common targets of genomic alterations in 42 hepatocellular carcinomas collected in western North-Africa. Overall, genomic instability was uncommon, allelic losses affecting mostly chromosomes 1p, 4q, 8p and 17p (24-28% of cases). CTNNB1 and TP53 were infrequently mutated (9 and 17% of cases, respectively). Surprisingly, TP53 mutation R249S, diagnostic of aflatoxin B1 exposure, usually frequent in Africa, was exceptional (one case), indicating that in western North-Africa, hepatocellular carcinoma genetics differs markedly from that of the remainder of the continent.

Novel adenine adducts, N7-guanine-AFB1 adducts, and p53 mutations in patients with schistosomiasis and aflatoxin exposure

INTRODUCTION

The most frequent mutation in human hepatocellular carcinoma (HCC) in populations exposed to a high dietary intake of aflatoxin B1 (AFB1) is a mutation in codon 249 of the p53 gene. Schistosomiasis is known to cause p53 mutation. We hypothesized that the combination of schistosomiasis and aflatoxin B1 increases the incidence of p53 gene mutation.

METHODS

Liver tissue from 21 patients with schistosomiasis and 5 patients without schistosomiasis were analyzed for occurrence of mutations of the p53 gene and levels of N7-guanine-AFB1 adducts.

RESULTS

The presence of mutations in codon 249 of p53 gene was higher in patients infected with Schistosoma haematobium (S. haematobium) than in those infected with Schistosoma mansoni (S. mansoni) or a combination of both strains (p < 0.01), compared to control subjects. No mutations were detected in p53 gene in liver DNA from schistosomiasis-free patients. Significant amounts of N7-guanine-AFB1 adducts and novel adenine-adducts (p < 0.01) were detected in patients with schistosomiasis, mostly in patients infected with S. haematobium or a combination of both strains, compared to control subjects.

CONCLUSION

These data suggest that schistosomiasis and exposure to aflatoxin B1 act synergistically to increase the incidence of p53 gene mutation. The increase in p53 mutations may enhance progression of HCC at an early age in patients with schistosomiasis.