Polycyclic aromatic hydrocarbons and esophageal squamous cell carcinoma

Contributing factors common to COVID‑19 and gastrointestinal cancer

The devastating complications of coronavirus disease 2019 (COVID-19) result from the dysfunctional immune response of an individual following the initial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Multiple toxic stressors and behaviors contribute to underlying immune system dysfunction. SARS-CoV-2 exploits the dysfunctional immune system to trigger a chain of events, ultimately leading to COVID-19. The authors have previously identified a number of contributing factors (CFs) common to myriad chronic diseases. Based on these observations, it was hypothesized that there may be a significant overlap between CFs associated with COVID-19 and gastrointestinal cancer (GIC). Thus, in the present study, a streamlined dot-product approach was used initially to identify potential CFs that affect COVID-19 and GIC directly (i.e., the simultaneous occurrence of CFs and disease in the same article). The nascent character of the COVID-19 core literature (~1-year-old) did not allow sufficient time for the direct effects of numerous CFs on COVID-19 to emerge from laboratory experiments and epidemiological studies. Therefore, a literature-related discovery approach was used to augment the COVID-19 core literature-based ‘direct impact’ CFs with discovery-based ‘indirect impact’ CFs [CFs were identified in the non-COVID-19 biomedical literature that had the same biomarker impact pattern (e.g., hyperinflammation, hypercoagulation, hypoxia, etc.) as was shown in the COVID-19 literature]. Approximately 2,250 candidate direct impact CFs in common between GIC and COVID-19 were identified, albeit some being variants of the same concept. As commonality proof of concept, 75 potential CFs that appeared promising were selected, and 63 overlapping COVID-19/GIC potential/candidate CFs were validated with biological plausibility. In total, 42 of the 63 were overlapping direct impact COVID-19/GIC CFs, and the remaining 21 were candidate GIC CFs that overlapped with indirect impact COVID-19 CFs. On the whole, the present study demonstrates that COVID-19 and GIC share a number of common risk/CFs, including behaviors and toxic exposures, that impair immune function. A key component of immune system health is the removal of those factors that contribute to immune system dysfunction in the first place. This requires a paradigm shift from traditional Western medicine, which often focuses on treatment, rather than prevention.

Risk Factors of Esophageal Squamous Cell Carcinoma beyond Alcohol and Smoking

Esophageal squamous cell carcinoma (ESCC) is the sixth most common cause of death worldwide. Incidence rates vary internationally, with the highest rates found in Southern and Eastern Africa, and central Asia. Initial observational studies identified multiple factors associated with an increased risk of ESCC, with subsequent work then focused on developing plausible biological mechanistic associations. The aim of this review is to summarize the role of risk factors in the development of ESCC and propose future directions for further research. A systematic search of the literature was conducted by screening EMBASE, MEDLINE/PubMed, and CENTRAL for relevant publications. In total, 73 studies were included that sought to identify risk factors associated with the development of esophageal squamous cell carcinoma. Risk factors were divided into seven subcategories: genetic, dietary and nutrition, gastric atrophy, infection and microbiome, metabolic, epidemiological and environmental and other risk factors. Risk factors from each subcategory were summarized and explored with mechanistic explanations for these associations. This review highlights several current risk factors of ESCC. These risk factors were explored, and explanations dissected. Most studies focused on investigating genetic and dietary and nutritional factors, whereas this review identified other potential risk factors that have yet to be fully explored. Furthermore, there is a lack of literature on the association of these risk factors with tumor factors and disease prognosis. Further research to validate these results and their effects on tumor biology is absolutely necessary.

Perceived role of hot food in the pathogenesis of oesophageal cancer: a qualitative study in the Arsi Zone, Oromia, Central Ethiopia

Observational studies in Ethiopia have identified a positive association between hot wheat porridge consumption and oesophageal carcinoma. However, a single dietary intake cannot be a sufficient predictor of cancer among populations that have diverse dietary practices. The present study was carried out to explore the community's perspectives on the role of hot foods in the pathogenesis of oesophageal cancer in Ethiopia. Focus group discussions were conducted from May to August 2019 among purposefully selected 112 participants. Data were collected by using open-ended questions; memo writing, audio recordings and photo pictures. All tape-recorded interviews were transcribed verbatim and inductively coded using Atlas.ti Version 7.0.71 software. Finally, the analysis was performed according to the standard thematic framework analysis techniques. The finding showed that hot foods (porridge, coffee and soup) consumption patterns were perceived as the principal dietary risk of oesophageal cancer. Cooking in unventilated rooms, monotonous cereal-based foods, poor vegetable, and fruit intake, not taking milk with porridge, eating fast, swallowing large bolus of hot porridge and exposure to carcinogens in foods were regarded as predisposing dietary practices to oesophageal carcinoma. Socio-demographic, economic and cultural backgrounds were reported as the underlying risk factors associated with oesophageal cancer. There was a strong perception within the community that oesophageal cancer is linked to several but sequentially interlinked dietary and related practices. Cumulative thermal injuries from the consumptions of hot food could be the immediate dietary risk factors associated with increased risk of oesophageal cancer.

Oesophageal cancer magnitude and presentation in Ethiopia 2012-2017

The aim of this study was to assess the magnitude, socio-demographic, and clinical characteristics of oesophageal cancer patients in selected referral hospitals of Ethiopia. A retrospective document review was employed in ten referral hospitals in different regions of Ethiopia. A structured data extraction tool was used to extract data from clinical care records of all clinically and pathologically confirmed oesophageal cancer patients who were diagnosed and treated in those hospitals from 2012 to 2017. During the study period, a total of 777 oesophageal cancer cases were identified, and the median age of these patients was 55 years, with an interquartile range of 19. More than half (55.1%, n = 428) of the cases were males, and the majority of them were reported from Oromia (49.9%, n = 388) and Somali (25.9%, n = 202) regional states. The highest numbers of oesophageal cancer cases were recorded in 2016 (23.8%, n = 185), while the lowest were in 2012 (12.6%, n = 98). Eighty per cent of oesophageal cancer cases were diagnosed in later stages of the disease. More than one-fourth (27.0%, n = 210) of patients had surgical procedures where the majority (74.3%, n = 156) required insertion of a feeding tube followed by transhiatal oesophagectomy (10.9%, n = 23). Of the 118 patients for which there was histology data, squamous cell carcinoma (56.7%, n = 67) and adenocarcinoma (36.4%, n = 43) were the predominant histologic type. One-fourth (25.0%, n = 194) of the patients were alive, and more than two-thirds (71.7%, n = 557) of the patients' current status was unknown at the time of the review. In these referral hospitals of Ethiopia, many oesophageal cancer patients presented during later stages of the disease and needed palliative care measures. The number of patients seen in Oromia and Somali hospitals by far exceeded hospitals of the other regions, thus postulating possibly unique risk factors in those geographic areas.

Gender Differences in Oesophageal Squamous Cell Carcinoma in a South African Tertiary Hospital

(1) Oesophageal squamous cell carcinoma is common in Africa and has a male preponderance. The gender-based differences in clinical presentation and risk factor exposure are poorly studied in the African context. Our aim was to compare males and females with this disease. We analyzed the differences in clinical features and risk factor exposure between males and females with oesophageal cancer. (2) Data from patients presenting to a tertiary hospital in South Africa with oesophageal squamous cell carcinoma were analyzed. Data collected included patient demographics, clinical presentation, pathology and risk factor exposure. (3) Three hundred and sixty three patients were included in the study. The male to female ratio was 1.4:1. The mean age was 66 years for females and 61 years for males (p < 0.0001). A significantly larger percentage of males were underweight compared to females (60% vs. 32%, p < 0.001). There were no differences between the genders with regards to performance status, dysphagia grade and duration and tumor length, location and degree of differentiation. There were significant differences between risk factor exposure between the two genders. Smoking and alcohol consumption was an association in more than 70% of males but in less than 10% of females There was no difference survival. (4) Female patients with oesophageal squamous cell carcinoma (OSCC) are older and have a higher body mass index (BMI) than their male counterparts. Traditionally purported risk factors of smoking and alcohol consumption are infrequent associations with OSCC in female patients and other environmental risk factors may be more relevant in this gender.

10-Year Trends in Dietary Intakes in the High- and Low-Risk Areas for Esophageal Cancer: A Population-Based Ecological Study in Northern Iran

BACKGROUND

We assessed dietary intakes in the high- and low-risk areas for esophageal cancer (EC) in Golestan province, Northern Iran.

METHODS

Considering the EC rates, Golestan province was divided into high- and low-risk regions. Data on households’ food consumption were obtained from the Statistical Center of Iran. We used multivariable logistic regression to assess the relationships between consumption of main food and EC risk. Adjusted odds ratios (aOR) were calculated. Joint point program was used for time trend analysis and average annual percent changes (AAPC) were reported.

RESULTS

Overall, 11910 households were recruited during 2006-2015. 4710 (39.5%) households were enrolled from the high-risk region. There were significant positive relationships between high consumption of sweets (aOR = 1.62; 95% CI: 1.24-2.10), oil/fat (aOR = 1.36; 95% CI: 1.04-1.79), and red meat (aOR = 1.33; 95% CI: 1.07-1.65) with EC risk. We found significant negative relationships between high consumption of dairy products (aOR = 0.62; 95% CI: 0.46-0.82), vegetables (aOR = 0.66; 95% CI: 0.50-0.87) and fruit (aOR = 0.72; 95% CI: 0.55-0.95) with the risk of EC. Time trend analysis showed a significant increasing trend in the proportions of households with low consumption of vegetables (AAPC = 4.71, p = 0.01) and dairy products (AAPC = 5.26, p = 0.02) in the low-risk region for EC.

CONCLUSION

Dietary intakes may be important etiological factors for EC in Northern Iran. Further studies are warranted to assess the role of dietary factors in this high-risk population.

Levels of PAH-DNA adducts in cord blood and cord tissue and the risk of fetal neural tube defects in a Chinese population

INTRODUCTION

Maternal exposure to polycyclic aromatic hydrocarbons (PAHs) has been shown to be associated with an elevated risk for neural tube defects (NTDs). In the human body, PAHs are bioactivated and the resultant reactive epoxides can covalently bind to DNA to form PAH-DNA adducts, which may, in turn, cause transcription errors, changes in gene expression or altered patterns of apoptosis. During critical developmental phases, these changes can result in abnormal morphogenesis.

OBJECTIVES

We aimed to examine the relationship between the levels of PAH-DNA adducts in cord blood and cord tissue and the risk of NTDs.

METHODS

From 2010 to 2012, 60 NTD cases and 60 healthy controls were recruited from a population-based birth defects surveillance system in five counties of Shanxi Province in Northern China, where the emission of PAHs remains one of the highest in the country and PAHs exposure is highly prevalent. PAH-DNA adducts in cord blood of 15 NTD cases and 15 control infants, and in cord tissue of 60 NTD cases and 60 control infants were measured using the (32)P-postlabeling method.

RESULTS

PAH-DNA adduct levels in cord blood tend to be higher in the NTD group (28.5 per 10(8) nucleotides) compared with controls (19.7 per 10(8) nucleotides), although the difference was not statistically significant (P=0.377). PAH-DNA adducts in cord tissue were significantly higher in the NTD group (24.6 per 10(6) nucleotides) than in the control group (15.3 per 10(6) nucleotides), P=0.010. A positive dose-response relationship was found between levels of PAH-DNA adducts in cord tissue and the risk of NTDs (P=0.009). When the lowest tertile was used as the referent and potential confounding factors were adjusted for, a 1.03-fold (95% CI, 0.37-2.89) and 2.96-fold (95% CI, 1.16-7.58) increase in the risk of NTDs was observed for fetuses whose cord tissue PAH-DNA adduct levels were in the second and highest tertile, respectively.

CONCLUSIONS

High levels of PAH-DNA adducts in fetal tissues were associated with increased risks of NTDs.

Cancer stem cell detection and isolation

Only 10 % of cancer-related deaths result from primary tumors; most are caused by metastatic tumors. It is believed that the metastatic power of tumor cells is attributed to features of a stem cell-like subpopulation of tumor cells known as cancer stem cells (CSCs). Cancer stem cells are resistant to chemotherapeutic treatments and can induce dormancy in tumor cells for long periods. Detection, isolation, and characterization of CSCs in solid tumors are hallmarks of cancer-targeted therapies in recent years. There are inevitable similarities between normal and cancer stem cells; therefore, finding specific methods or markers to differentiate them is critical to cancer therapies. Considering CSCs involvement in tumor relapse and chemotherapeutic resistance, identification of such cells in tumors is imperative for effective targeted therapy. The present review introduces practical and specific protocols used to isolate CSCs from solid tumors from colon, esophagus, liver, breast, brain, and cervix.

CYP1A1 and CYP2E1 genotypes and risk of esophageal squamous cell carcinoma in a high-incidence region, Kashmir

The study analyzed the relationship between genetic polymorphisms of phase I xenobiotic metabolizing enzymes, cytochromes P450 (CYP) 1A1 and CYP2E1 and esophageal squamous cell carcinoma (ESCC) in Kashmir, India. The different genotypes of CYP1A1 and CYP2E1 were analyzed by polymerase chain reaction and restriction fragment length polymorphism in 526 ESCC cases and equal number of matched controls. Conditional logistic regression models were used to assess the association of various genotypes with ESCC, gene-gene, and gene-environment interactions. High risk of ESCC was found in participants who carried CYP1A1 Val/Val genotype (OR=2.87; 95 % CI=1.00-8.44) and the risk increased in such individuals when c1/c1 of CYP2E1 genotype was also present (OR=5.68; 95 % CI=1.09-29.52). Risk due to CYP1A1 Val/Val genotype was further enhanced (OR=8.55; 95 % CI=1.86-42.20) when the analysis was limited to ever smokers. Participants who carried CYP2E1 c1/c2 genotype showed an inverse relation (OR=0.27; 95 % CI=0.17-0.43) with ESCC. The inverse association of CYP2E1 c1/c2 genotype was retained when CYP1A1 Ile/Ile was also present (OR=0.18; 95 % CI=0.09-0.32), as well as when analysis was limited to ever smokers (OR=0.45; 95 % CI=0.23-0.90). Significant interaction was found between CYP1A1 (Val/Val) and CYP2E1 (c1/c1) genotypes (OR=1.30; 95 % CI=1.12-1.51; P=0.001) and between CYP1A1 (Val/Val) and smoking (OR=1.31; 95 % CI=1.01-1.69; P=0.043). The study suggests CYP1A1 Val/Val and CYP2E1 c1/c1 genotypes are significantly associated with ESCC risk.