hOGG1: A novel mediator in nitrosamine-induced esophageal tumorigenesis

BACKGROUND

The effect of human 8-Oxoguanine DNA Glycosylase (hOGG1) on exogenous chemicals in esophageal squamous cell carcinoma (ESCC) remain unclear. The study plans to determine hOGG1 expression levels in ESCC and possible interactions with known environmental risk factors in ESCC.

MATERIAL AND METHODS

We analyzed levels of exposure to urinary nitrosamines in volunteers from high and low prevalence areas by GC-MS. And we performed the interaction between hOGG1 gene and nitrosamine disinfection by-products by analyzing hOGG1 gene expression in esophageal tissues.

RESULTS

In ESCC, nitrosamine levels were significantly increased and hOGG1 mRNA expression levels were significantly decreased. There was a statistically significant interaction between reduced hOGG1 mRNA levels and non-tap drinking water sources in ESCC. The apparent indirect association between ESCC and NMEA indicated that 33.4% of the association between ESCC and NMEA was mediated by hOGG1.

CONCLUSION

In populations which exposed to high levels of environmental pollutants NDMA, low expression of hOGG1 may promote the high incidence of esophageal cancer in Huai'an. hOGG1 may be a novel mediator in nitrosamine-induced esophageal tumorigenesis.

First-line sugemalimab with chemotherapy for advanced esophageal squamous cell carcinoma: a randomized phase 3 study

Although antiprogrammed death 1 antibody plus chemotherapy has recently been approved for first-line esophageal squamous cell carcinoma (ESCC), antiprogrammed death-ligand 1 antibody may offer another combination option in this setting. In this multicenter, randomized, double-blinded phase 3 trial a total of 540 adults (aged 18-75 years) with unresectable, locally advanced, recurrent or metastatic ESCC and who had not received systemic treatment were enrolled. All patients were randomized at 2:1 to receive either sugemalimab (an anti-PD-L1 antibody; 1,200 mg) or placebo every 3 weeks for up to 24 months, plus chemotherapy (cisplatin 80 mg m-2 on day 1 plus 5-fluorouracil 800 mg m-2 day-1 on days 1-4) every 3 weeks for up to six cycles. At the prespecified interim analysis this study had met dual primary endpoints. With a median follow-up of 15.2 months, the prolongation of progression-free survival was statistically significant with sugemalimab plus chemotherapy compared with placebo plus chemotherapy (median 6.2 versus 5.4 months, hazard ratio 0.67 (95% confidence interval 0.54-0.82), P = 0.0002) as assessed by blinded independent central review. Overall survival was also superior with sugemalimab chemotherapy (median 15.3 versus 11.5 months, hazard ratio 0.70 (95% confidence interval 0.55-0.90, P = 0.0076). A significantly higher objective response rate (60.1 versus 45.2%) as assessed by blinded independent central review was observed with sugemalimab chemotherapy. The incidence of grade 3 or above treatment-related adverse events (51.3 versus 48.4%) was comparable between the two groups. Sugemalimab plus chemotherapy significantly prolonged progression-free survival and overall survival in treatment-naïve patients with advanced ESCC, with no unexpected safety signal. The ClinicalTrials.gov identifier is NCT04187352 .

Tislelizumab in advanced/metastatic esophageal squamous cell carcinoma: health-related quality of life in Asian patients

OBJECTIVE

Post-hoc analysis examined health-related quality of life and esophageal squamous cell carcinoma (ESCC) symptoms in the Asian subgroup of patients in RATIONALE-302 (NCT03430843).

METHODS

Patients were randomized 1:1 to either tislelizumab or investigator-chosen chemotherapy (paclitaxel, docetaxel, or irinotecan). Health-related quality of life was measured using the EORTC QLQ-C30 and the QLQ-OES18. Least-squares mean score changes from baseline to weeks 12 and 18 in health-related quality-of-life scores were assessed using a mixed model for repeated measurements. Reported nominal p-values are for descriptive purposes only.

RESULTS

Of the 512 patients, this analysis was conducted in 392 Asian patients (tislelizumab, n = 192; investigator-chosen chemotherapy, n = 200). The tislelizumab arm had stable global health status/quality of life, but fatigue scores worsened in both arms. The change from baseline was similar for physical functioning in both arms at weeks 12 and 18. Eating and dysphagia scores remained stable in the tislelizumab arm. Reflux improved at week 12 in the tislelizumab arm and worsened in the investigator-chosen chemotherapy arm.

CONCLUSIONS

Overall, the health-related quality of life and ESCC-related symptoms of patients receiving tislelizumab in the Asian subgroup remained stable or improved, while patients receiving investigator-chosen chemotherapy experienced worsening. These results in Asian patients corroborate the findings in the intent-to-treat population, suggesting tislelizumab is a potential new second-line treatment option for patients with advanced or metastatic ESCC.

TRIAL REGISTRATION

The RATIONALE-302 study is registered on clinicaltrials.gov as NCT03430843.

Narrow-band imaging vs Lugol chromoendoscopy in screening for esophageal squamous cell neoplasia: a randomized trial

INTRODUCTION

To date, there is no established optimal method for endoscopic detection of esophageal squamous cell neoplasia in high‑risk individuals.

OBJECTIVES

We aimed to compare the performance of narrow‑band imaging (NBI) and Lugol chromoendoscopy in screening for esophageal neoplasia among patients with a history of treatment for head and neck squamous cell cancer (HNSCC).

PATIENTS AND METHODS

We randomly assigned 300 patients who had completed curative treatment for HNSCC at least 1 year prior to the inclusion to undergo either NBI or Lugol endoscopy (2:1 ratio). Following white‑light examination of the esophagus, the assigned imaging study was performed, and biopsies were taken from any suspicious lesions identified using NBI or Lugol chromoendoscopy. The primary end point was positive predictive value (PPV) of the biopsied lesion for a diagnosis of esophageal neoplasia (high‑grade intraepithelial neoplasia [HG‑IEN] or invasive esophageal squamous cell carcinoma [ESCC]). The secondary end points included the number of biopsied lesions, duration of esophagus examination, and endoscopy tolerance.

RESULTS

In 294 patients included in the final analysis (NBI, n = 204; Lugol chromoendoscopy, n = 90), we diagnosed 3 ESCCs (1.02%) and 2 HG‑IENs (0.68%). The PPV of NBI and Lugol chromoendoscopy in per‑lesion analysis was 7.69% (95% CI, 0.94%-25.1%) and 8.11% (95% CI, 1.7%-21.9%), respectively (P >0.99). NBI outperformed Lugol chromoendoscopy in terms of the rate of patients requiring biopsy (12.75% vs 41.11%; P = 0.003), duration of esophagus examination (3.5 min vs 5.15 min; P <0.001), and endoscopy tolerance assessed on the visual analog scale (25 mm vs 36.5 mm; P = 0.002).

CONCLUSIONS

With a PPV comparable to that of Lugol chromoendoscopy, but a lower number of biopsies required, shorter examination time, and better patient tolerance, NBI could be considered the primary screening method for ESCC in patients with HNSCC.

First-line serplulimab or placebo plus chemotherapy in PD-L1-positive esophageal squamous cell carcinoma: a randomized, double-blind phase 3 trial

First-line systemic therapeutic options for advanced esophageal squamous cell carcinoma (ESCC) are limited. In this multicenter, double-blind phase 3 trial, a total of 551 patients with previously untreated, locally advanced or metastatic ESCC and PD-L1 combined positive score of ≥1 were randomized (2:1) to receive serplulimab (an anti-PD-1 antibody; 3 mg/kg) or placebo (on day 1), plus cisplatin (50 mg/m2) (on day 1) and continuous infusion of 5-fluorouracil (1,200 mg/m2) (on days 1 and 2), once every 2 weeks. The study met the primary endpoints. At the prespecified final analysis of progression-free survival (PFS) assessed by the blinded independent radiological review committee, serplulimab plus chemotherapy significantly improved PFS compared with placebo plus chemotherapy (median PFS of 5.8 months and 5.3 months, respectively; hazard ratio, 0.60; 95% confidence interval, 0.48-0.75; P < 0.0001). At the prespecified interim analysis of overall survival (OS), serplulimab plus chemotherapy also significantly prolonged OS compared with placebo plus chemotherapy (median OS of 15.3 months and 11.8 months, respectively; hazard ratio, 0.68; 95% confidence interval, 0.53-0.87; P = 0.0020). Grade 3 or higher treatment-related adverse events occurred in 201 (53%) and 81 (48%) patients in the serplulimab plus chemotherapy group and the placebo plus chemotherapy group, respectively. Serplulimab plus chemotherapy administered every 2 weeks significantly improved PFS and OS in patients with previously untreated, PD-L1-positive advanced ESCC, with a manageable safety profile. This study is registered with ClinicalTrials.gov ( NCT03958890 ).

N-nitrosamines-mediated downregulation of LncRNA-UCA1 induces carcinogenesis of esophageal squamous by regulating the alternative splicing of FGFR2

Concerns are raised over the risk to digestive system's tumors from the N-nitrosamines (NAs) exposure in drinking water. Albeit considerable studies are conducted to explore the underlying mechanism responsible for NAs-induced esophageal squamous cell carcinoma (ESCC), the exact molecular mechanisms remain largely unknown, especially at the epigenetic regulation level. In this study, it is revealed that the urinary concentration of N-Nitrosodiethylamine is higher in high incidence area of ESCC, and the lncRNA-UCA1(UCA1) is significantly decreased in ESCC tissues. In vitro and in vivo experiments further show that UCA1 is involved in the malignant transformation of Het-1A cells and precancerous lesions of the rat esophagus induced by N-nitrosomethylbenzylamine (NMBzA). Functional gain and loss experiments verify UCA1 can affect the proliferation, migration, and invasion of ESCC cells in vitro and in vivo. Mechanically, through binding to heterogeneous nuclear ribonucleoprotein F (hnRNP F) protein, UCA1 regulates alternative splicing of fibroblast growth factor receptor 2 (FGFR2), which promotes the FGFR2IIIb isoform switching to FGFR2 IIIc isoform, and the latter activates epithelial-mesenchymal transition via PI3K-AKT signaling pathways impacting tumorigenesis. Therefore, NAs-mediated downregulation of UCA1 promotes ESCC progression through targeting hnRNP F/FGFR2/PI3k-AKT axis, which provides a new chemical carcinogenic target and establishes a previously unknown mechanism for NAs-induced ESCC.

Esophageal Squamous Cancer from 4NQO-Induced Mice Model: CNV Alterations

Squamous esophageal carcinoma is a common pathological type of esophageal carcinoma around the world. The prognosis of esophageal carcinoma is usually poor and diagnosed at late stages. Recently, research suggested that genomic instability occurred in esophageal cells during the development of esophageal squamous cell carcinoma (ESCC). Identifying prognostic and specific genomic characteristics, especially at the early hyperplasia stage, is critical. Mice were given 4-nitroquinoline 1-oxide (4NQO) with drinking water to induce esophageal cancer. The immortalized human esophageal epithelial cell line (NE2) was also treated with 4NQO. We performed histologic analyses, immunofluorescence, and immunohistochemical staining to detect DNA damage at different time points. Whole-exome sequencing was accomplished on the esophagus tissues at different pathological stages to detect single-nucleotide variants and copy number variation (CNV) in the genome. Our findings indicate that all mice were tumor-forming, and a series of changes from simple hyperplasia (ESSH) to intraepithelial neoplasia (IEN) to esophageal squamous cell carcinoma (ESCC) was seen at different times. The expression of γ-H2AX increased from ESSH to ESCC. In addition, mutations of the Muc4 gene were detected throughout the pathological stages. Furthermore, CNV burden appeared in the esophageal tissues from the beginning of ESSH and accumulated more in cancer with the deepening of the lesions. This study demonstrates that mutations caused by the early appearance of DNA damage may appear in the early stage of malignant tissue before the emergence of atypia. The detection of CNV and mutations of the Muc4 gene may be used as an ultra-early screening indicator for esophageal cancer.

Risk Factors Related to Esophageal Cancer, a Case-Control Study in Herat Province of Afghanistan

BACKGROUND

The Herat province of Afghanistan is located on the Asian Esophageal Cancer Belt (AECB), a wide area in Central and Eastern Asia where very high rates of esophageal cancer (EC) have been observed. Several risk factors have been reported in the AECB Region by previous studies. Considering lack of information in Afghanistan on this issue, a study was conducted to determine the major risk factors related to EC in order to guide protective measures.

METHODS

A population-based case-control study was performed from July 2015 to August 2016 among 657 EC patients in the Herat Province and 180 histopathological confirmed cases and 189 controls were interviewed. A structured questionnaire was used and face-to-face interviews were conducted.

RESULTS

Low body mass index (BMI), low socio-economic status, family history of EC, consumption of dark tea, very hot beverage and qulurtoroosh were found to be statistically significant for EC and esophageal squamous cell carcinoma (ESCC) in univariate analyses. According to multivariate analyses, sex (OR=2.268; 95% CI=1.238-4.153), very hot beverages (OR=2.253; 95% CI=1.271- 3.996), qulurtoroosh (OR=5.679; 95% CI=1.787-18.815), dark tea (OR=2.757; 95% CI=1.531-4.967), high previous BMI (OR=0.215; 95% CI=0.117-0.431) and low socio-economic status (OR=1.783; 95% CI=1.007-3.177) were associated with ESCC. Being male was found to increase the risk of ESCC with OR=2.268 (95% CI=1.238-4.153).

CONCLUSION

Consuming very hot beverages dark tea and a local food, qulurtoroosh, were found as important risk factors for EC. Our findings warrant further studies and necessitate the implementation of protective measures for EC which is one of the leading cancers in the region.

Metabolomic transition trajectory and potential mechanisms of N-nitrosomethylbenzylamine induced esophageal squamous cell carcinoma in rats

Esophageal squamous cell carcinoma (ESCC) is an environment-relevant malignancy with a high mortality. Nitrosamines, a class of nitrogen-containing environmental carcinogens, are widely suggested as a risk factor for ESCC. However, how nitrosamines affect metabolic regulation to promote ESCC tumorigenesis is largely unknown. In this study, the transition trajectory of serum metabolism in the course of ESCC induced by N-nitrosomethylbenzylamine (NMBA) in rats was depicted by an untargeted metabolomic analysis, and the potential molecular mechanisms were revealed. The results showed that the metabolic alteration in rats was slight at the basal cell hyperplasia (BCH) stage, while it became apparent when the esophageal lesion developed into dysplasia (DYS) or more serious conditions. Moreover, serum metabolism of severe dysplasia (S-DYS) showed more similar characteristics to that of carcinoma in situ (CIS) and invasive cancer (IC). Aberrant nicotinate (NA) and nicotinamide (NAM) metabolism, tryptophan (TRP) metabolism, and sphingolipid metabolism could be the key players favoring the malignant transformation of esophageal epithelium induced by NMBA. More particularly, NA and NAM metabolism in the precancerous stages and TRP metabolism in the cancerous stages were demonstrated to replenish NAD⁺ in different patterns. Furthermore, both the IDO1-KYN-AHR axis mediated by TRP metabolism and the SPHK1-S1P-S1PR1 axis by sphingolipid metabolism provided an impetus to create the pro-inflammatory yet immune-suppressive microenvironment to facilitate the esophageal tumorigenesis and progression. Together, these suggested that NMBA exerted its carcinogenicity via more than one pathway, which may act together to produce combination effects. Targeting these pathways may open up the possibility to attenuate NMBA-induced esophageal carcinogenesis. However, the interconnection between different metabolic pathways needs to be specified further. And the integrative and multi-level systematic research will be conducive to fully understanding the mechanisms of NMBA-induced ESCC.

Cost-Effectiveness of Nivolumab Immunotherapy vs. Paclitaxel or Docetaxel Chemotherapy as Second-Line Therapy in Advanced Esophageal Squamous Cell Carcinoma in China

This study aimed to evaluate and compare nivolumab's cost-effectiveness with chemotherapy in patients with advanced esophageal squamous cell carcinoma from the Chinese healthcare system perspective. To this end, the researchers utilized a partitioned survival model with three mutually exclusive health stages. The characteristics of the patients used as inclusion and exclusion criteria in this model were the same as those used for patients with advanced esophageal squamous cell carcinoma in the ATTRACTION-3 study. The ATTRACTION-3 trial, which took place between January 7, 2016 and November 12, 2018, also yielded important clinical data. Data on medical and economic preferences were collected from real-world clinical practices. Costs, quality-adjusted life years, and incremental cost-effectiveness ratio were calculated for the two therapy options. The model uncertainty was investigated using a deterministic and probabilistic sensitivity analysis. When compared to chemotherapy, nivolumab was linked with an increase of 0.28 quality-adjusted life years with an increased cost of US$ 36,956.81 per patient in the base case analysis of a hypothetical sample of 419 patients. The incremental cost-effectiveness ratio in the deterministic sensitivity analysis was US$ 132,029.46/quality-adjusted life year, with a 48.02% probability of being cost-effective at willingness-to-pay thresholds of US$ 132,029.22/quality-adjusted life year. The incremental cost-effectiveness ratio remained greater than US$ 80,000/quality-adjusted life year in the deterministic sensitivity analyses. To be more cost-effective and remain below the threshold of 37,653 US$/quality-adjusted life year, which the Chinese population can afford, nivolumab's price would have to be lowered sharply by 53.50%. Nivolumab is clinically beneficial but not cost-effective when compared to chemotherapy. A substantial reduction in nivolumab's drug acquisition cost would be necessary to make it cost-effective for immunotherapy.

Aspirin enhances the therapeutic efficacy of cisplatin in oesophageal squamous cell carcinoma by inhibition of putative cancer stem cells

BACKGROUND

Cancer stem cells (CSCs) are related to the patient's prognosis, recurrence and therapy resistance in oesophageal squamous cell carcinoma (ESCC). Although increasing evidence suggests that aspirin (acetylsalicylic acid, ASA) could lower the incidence and improve the prognosis of ESCC, the mechanism(s) remains to be fully understood.

METHODS

We investigated the role of ASA in chemotherapy/chemoprevention in human ESCC cell lines and an N-nitrosomethylbenzylamine-induced rat ESCC carcinogenesis model. The effects of combined treatment with ASA/cisplatin on ESCC cell lines were examined in vitro and in vivo. Sphere-forming cells enriched with putative CSCs (pCSCs) were used to investigate the effect of ASA in CSCs. Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) was performed to determine the alterations in chromatin accessibility caused by ASA in ESCC cells.

RESULTS

ASA inhibits the CSC properties and enhances cisplatin treatment in human ESCC cells. ATAC-seq indicates that ASA treatment results in remarkable epigenetic alterations on chromatin in ESCC cells, especially their pCSCs, through the modification of histone acetylation levels. The epigenetic changes activate Bim expression and promote cell death in CSCs of ESCC. Furthermore, ASA prevents the carcinogenesis of NMBzA-induced ESCC in the rat model.

CONCLUSIONS

ASA could be a potential chemotherapeutic adjuvant and chemopreventive drug for ESCC treatment.

Repurposing dextromethorphan and metformin for treating nicotine-induced cancer by directly targeting CHRNA7 to inhibit JAK2/STAT3/SOX2 signaling

Smoking is one of the most impactful lifestyle-related risk factors in many cancer types including esophageal squamous cell carcinoma (ESCC). As the major component of tobacco and e-cigarettes, nicotine is not only responsible for addiction to smoking but also a carcinogen. Here we report that nicotine enhances ESCC cancer malignancy and tumor-initiating capacity by interacting with cholinergic receptor nicotinic alpha 7 subunit (CHRNA7) and subsequently activating the JAK2/STAT3 signaling pathway. We found that aberrant CHRNA7 expression can serve as an independent prognostic factor for ESCC patients. In multiple ESCC mouse models, dextromethorphan and metformin synergistically repressed nicotine-enhanced cancer-initiating cells (CIC) properties and inhibited ESCC progression. Mechanistically, dextromethorphan non-competitively inhibited nicotine binding to CHRNA7 while metformin downregulated CHRNA7 expression by antagonizing nicotine-induced promoter DNA hypomethylation of CHRNA7. Since dextromethorphan and metformin are two safe FDA-approved drugs with minimal undesirable side-effects, the combination of these drugs has a high potential as either a preventive and/or a therapeutic strategy against nicotine-promoted ESCC and perhaps other nicotine-sensitive cancer types as well.

Cigarette Smoke Extract induces H19 in Esophageal Squamous Cell Carcinoma in Smoking Patients: Based on A Chronic Exposed Cell Model

Cigarette smoking is a factor capable of inducing esophageal squamous cell carcinoma (ESCC). However, the biological pathways that are responsible for tumor development and are directly affected by cigarette smoking remain unknown. To explore the role of cigarette smoking in ESCC, we developed a long-term cigarette smoke extract (CSE) exposed cell model using the normal immortalized SHEE esophageal epithelial cell line, which would malignantly transform after long-term cultivation without carcinogens. CSE-exposed cells displayed higher malignancy and differently expressed several lncRNAs. Among them, H19, a lncRNA responsible for proliferation and invasion, was upregulated in CSE-exposed SHEE cells. In tumors from ESCC patients, H19 was significantly increased in smoking ESCC patients compared to non-smoking patients, and H19 was overexpressed and correlated with pathological tumor size in smokers. These results indicated that cigarette smoking lead to a different biological change from non-smoking induced ESCC and H19 related to cancer development during CSE-induced carcinogenesis.

Low-Dose Metformin Reprograms the Tumor Immune Microenvironment in Human Esophageal Cancer: Results of a Phase II Clinical Trial

PURPOSE

The tumor immune microenvironment (TIME) has an important impact on response to cancer immunotherapy using immune checkpoint inhibitors. Specifically, an "infiltrated-excluded"/"cold" TIME is predictive of poor response. The antidiabetic agent metformin may influence anticancer immunity in esophageal squamous cell carcinoma (ESCC).

EXPERIMENTAL DESIGN

We analyzed matched pre- and posttreatment ESCC specimens in a phase II clinical trial of low-dose metformin treatment (250 mg/day) to evaluate direct anti-ESCC activity and TIME reprogramming. Follow-up correlative studies using a carcinogen-induced ESCC mouse model were performed with short-term (1 week) or long-term (12 weeks) low-dose metformin (50 mg/kg/day) treatment.

RESULTS

In the clinical trial, low-dose metformin did not affect proliferation or apoptosis in ESCC tumors as assayed by Ki67 and cleaved caspase-3 immunostaining. However, metformin reprogrammed the TIME toward "infiltrated-inflamed" and increased the numbers of infiltrated CD8⁺ cytotoxic T lymphocyte and CD20⁺ B lymphocyte. Further, an increase in tumor-suppressive (CD11c⁺) and a decrease in tumor-promoting (CD163⁺) macrophages were observed. Metformin augmented macrophage-mediated phagocytosis of ESCC cells in vitro. In the ESCC mouse model, short-term metformin treatment reprogrammed the TIME in a similar fashion to humans, whereas long-term treatment further shifted the TIME toward an active state (e.g., reduction in CD4⁺ FoxP3⁺ regulatory T cells) and inhibited ESCC growth. In both humans and mice, metformin triggered AMPK activation and STAT3 inactivation, and altered the production of effector cytokines (i.e., TNFα, IFNγ, and IL10) in the immune cells.

CONCLUSIONS

Low-dose metformin reprograms the TIME to an activated status and may be a suitable immune response modifier for further investigation in patients with ESCC.

Abrogation of esophageal carcinoma development in miR-31 knockout rats

MicroRNA-31 (miR-31) is overexpressed in esophageal squamous cell carcinoma (ESCC), a deadly disease associated with dietary Zn deficiency and inflammation. In a Zn deficiency-promoted rat ESCC model with miR-31 up-regulation, cancer-associated inflammation, and a high ESCC burden following N-nitrosomethylbenzylamine (NMBA) exposure, systemic antimiR-31 delivery reduced ESCC incidence from 85 to 45% (P = 0.038) and miR-31 gene knockout abrogated development of ESCC (P = 1 × 10-6). Transcriptomics, genome sequencing, and metabolomics analyses in these Zn-deficient rats revealed the molecular basis of ESCC abrogation by miR-31 knockout. Our identification of EGLN3, a known negative regulator of nuclear factor κB (NF-κB), as a direct target of miR-31 establishes a functional link between oncomiR-31, tumor suppressor target EGLN3, and up-regulated NF-κB-controlled inflammation signaling. Interaction among oncogenic miR-31, EGLN3 down-regulation, and inflammation was also documented in human ESCCs. miR-31 deletion resulted in suppression of miR-31-associated EGLN3/NF-κB-controlled inflammatory pathways. ESCC-free, Zn-deficient miR-31-/- rat esophagus displayed no genome instability and limited metabolic activity changes vs. the pronounced mutational burden and ESCC-associated metabolic changes of Zn-deficient wild-type rats. These results provide conclusive evidence that miR-31 expression is necessary for ESCC development.

Mycotoxin exposure is associated with increased risk of esophageal squamous cell carcinoma in Huaian area, China

BACKGROUND

Consumption of moldy food has previously been identified as a risk factor for esophageal squamous cell carcinoma (ESCC) in high-risk countries; however, what contributing roles these dietary carcinogenic mycotoxins play in the etiology of ESCC are largely unknown.

METHODS

A mycotoxin biomarker-incorporated, population-based case-control study was performed in Huaian area, Jiangsu Province, one of the two high-risk areas in China. Exposure biomarkers of aflatoxins (AF) and fumonisins (FN) were quantitatively analyzed using HPLC-fluorescence techniques.

RESULTS

Among the cases (n = 190), the median levels of AF biomarker, serum AFB1-lysine adduct, and FN biomarker, urinary FB1, were 1.77 pg/mg albumin and 176.13 pg/mg creatinine, respectively. Among the controls (n = 380), the median levels of AFB1-lysine adduct and urinary FB1 were 1.49 pg/mg albumin and 56.92 pg/mg creatinine, respectively. These mycotoxin exposure biomarker levels were significantly higher in cases as compared to controls (p <  0.05 and 0.01, respectively). An increased risk to ESCC was associated with exposure to both AFB1 and FB1 (p <  0.001 for both).

CONCLUSIONS

Mycotoxin exposure, especially to AFB1 and FB1, was associated with the risk of ESCC, and a greater-than-additive interaction between co-exposures to these two mycotoxins may contribute to the increased risk of ESCC in Huaian area, China.

Biomass fuel as a risk factor for esophageal squamous cell carcinoma: a systematic review and meta-analysis

BACKGROUND

The link between use of solid biomass fuel (wood, charcoal, coal, dung, and crop residues) for cooking and/or heating and esophageal squamous cell carcinoma (ESCC) is inconclusive.

OBJECTIVE

We systematically reviewed the literature and performed a meta-analysis to determine whether cooking fuel type influences esophageal squamous cell carcinoma.

METHODS

We searched MEDLINE, EMBASE, Web of Knowledge and Cochrane Database of Systematic Reviews for studies investigating cooking fuel and ESCC from 2000 until March 2019. We performed random effects meta-analysis stratified by the continent, World Bank's country income classifications and fuel type and calculated pooled odds ratios and 95% CIs for the risk of esophageal squamous cell carcinoma in biomass fuel users compared with non-users.

RESULTS

Our analysis included 16 studies (all case-control) with 16,189 participants (5233 cases and 10,956 controls) that compared risk of ESCC among those using nonsolid fuels and biomass fuels. We found use of biomass fuel was associated with Esophageal squamous cell carcinoma with a pooled odds ratio (OR) 3.02 (95% CI 2.22, 4.11, heterogeneity (I2) = 79%). In sub-group analyses by continent, Africa (OR 3.35, 95%CI 2.34, 4.80, I2 = 73.4%) and Asia (OR 3.08, 95%CI 1.27, 7.43, I2 = 81.7%) had the highest odds of ESCC. Use of wood as fuel had the highest odds of 3.90, 95% CI 2.25, 6.77, I2 = 63.5%). No significant publication bias was detected.

CONCLUSIONS

Biomass fuel is associated with increased risk of Esophageal squamous cell carcinoma. Biomass fuel status should be considered in the risk assessment for Esophageal squamous cell carcinoma.

A possible role of biogenic silica in esophageal cancer in North China?

Certain areas in North China have the highest incidence of esophageal squamous cell carcinoma (ESCC) in the world, which has not seen convincing explanation by any risk factor yet. Biogenic silica in millet bran was linked to ESCC in the early 1980s but the hypothesis was largely dismissed because of the lack of geographic correlation between millet consumption and ESCC. Later epidemiological studies disclosed the linkage of wheat consumption in North China to ESCC instead. Now, we hypothesize silica phytoliths (silicified bodies that have definite shapes) from wheat chaff are a major etiologic factor of ESCC in this region. This hypothesis is supported by the potentially high abundance of silica phytoliths on the bracts of wheat (Triticum aestivum) in North China due to favorable Si-accumulation genotype, arid climate, and siallitic soil with bioavailable Si. These silica phytoliths can contaminate wheat flour and cause repeated local injuries in the esophagus and stimulate proliferation by providing anchorage.