Dietary exposure to nitrite and nitrosamines and risk of nasopharyngeal carcinoma in Taiwan

Astaxanthin suppresses the malignant behaviors of nasopharyngeal carcinoma cells by blocking PI3K/AKT and NF-κB pathways via miR-29a-3p

BACKGROUND

As a natural extraction, astaxanthin is gaining increasing attention because of its safety and anti-tumor properties. It has been reported to participate in the progression of various types of cancer such as gastric cancer and ovarian cancer. Nevertheless, the role of astaxanthin in nasopharyngeal carcinoma (NPC) has not been investigated.

OBJECT

The study aimed to explore the anticancer mechanism of astaxanthin in regulating NPC cell proliferation, cell cycle progression, apoptosis, migration, and invasion.

METHODS

Human NPC cells (C666-1) were treated with different concentrations of astaxanthin (0, 1, 10, 20 mg/mL) followed by detection of cell viability. Then, C666-1 cell proliferation, apoptosis, cell cycle progression, invasion, and migration in response to 10 mg/mL astaxanthin, LY294002 (PI3K/AKT inhibitor) or parthenolide (PTL; NF-κB inhibitor) treatment were measured using cell counting kit-8 assay, colony forming assay, flow cytometry analyses, Transwell assay, and wound healing assay, respectively. Western blotting was performed to quantify protein levels of factors involved in PI3K/AKT and NF-κB signaling pathways, cell cycle phase markers (Cyclin D1, p21) and apoptotic markers (Bcl-2 and Bax).

RESULTS

C666-1 cell proliferation, invasion, and migration were significantly suppressed by astaxanthin while cell apoptosis and cell cycle arrest at G1 phase were effectively enhanced in the context of 10 mg/mL astaxanthin. Protein levels of p-AKT, p-P65 and p-IκB levels were suppressed by astaxanthin treatment. After LY294002 or PTL treatment, the suppressive impact of astaxanthin on C666-1 cell process was strengthened, accompanied by the more obvious decrease in cell activity and cell colony number, more enhanced cell apoptosis and G1 phase arrest, and further inhibited cell migration and invasion. Moreover, the inhibitory effect of astaxanthin on Cyclin D1 and Bcl-2 protein levels as well as the promoting impact of astaxanthin on p21 and Bax were also amplified in combination with LY294002 or PTL treatment.

CONCLUSIONS

Astaxanthin significantly suppresses NPC cell proliferation, cell cycle arrest, migration, invasion while promoting cell apoptosis by inactivating PI3K/AKT and NF-κB pathways. The study first reveals the anticancer role of astaxanthin in NPC, providing a potential candidate for NPC treatment.

Neutrophil-to-lymphocyte ratio and monocyte-to-eosinophil ratio as prognostic indicators for advanced nasopharyngeal carcinoma

OBJECTIVE

To determine the predictive value of the neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), neutrophil-to-eosinophil ratio (NER), lymphocyte-to-eosinophil ratio (LER), monocyte-to-eosinophil ratio (MER), systemic inflammatory response index (SIRI), and ratio of inflammatory cells before and after treatment for predicting survival in advanced nasopharyngeal carcinoma (NPC) and to provide a reference for treatment.

METHODS

A retrospective review of 70 patients was performed. Serological indexes were obtained by drawing blood before and after systemic therapy. The cutoff values of these indexes were determined by receiver operating characteristic (ROC) curves. The prognostic value of the indexes for overall survival (OS) and distant metastasis free survival (DMFS) was evaluated.

RESULTS

Survival analysis showed that a smaller pretreatment LMR value was associated with poor OS; larger pretreatment NER, LER, MER, and SIRI values were associated with poor OS; a smaller posttreatment LMR value was associated with poor OS; larger posttreatment NLR, NER, MER, and SIRI values were associated with poor OS; a smaller pretreatment LMR value was associated with poor DMFS; larger pretreatment NLR, NER, LER, and MER values were associated with poor DMFS; and larger posttreatment NLR, NER, LER, and MER values were associated with poor DMFS. Furthermore, a larger neutrophil after treatment-to-neutrophil before treatment ratio was associated with poor OS and DMFS. Logistic regression analysis showed that pretreatment MER and posttreatment NLR were independent predictors of OS in patients with advanced NPC; moreover, pretreatment and posttreatment MER and NLR were independent prognostic factors for DMFS in patients with advanced NPC.

CONCLUSIONS

The NLR, NER and MER can be used to predict survival in advanced NPC patients. Eosinophils might be one of the factors for the good prognosis of NPC patients. In addition, an increased number of neutrophils after treatment may indicate a favorable prognosis.

Risk assessment of N-nitrosamines in food

EFSA was asked for a scientific opinion on the risks to public health related to the presence of N-nitrosamines (N-NAs) in food. The risk assessment was confined to those 10 carcinogenic N-NAs occurring in food (TCNAs), i.e. NDMA, NMEA, NDEA, NDPA, NDBA, NMA, NSAR, NMOR, NPIP and NPYR. N-NAs are genotoxic and induce liver tumours in rodents. The in vivo data available to derive potency factors are limited, and therefore, equal potency of TCNAs was assumed. The lower confidence limit of the benchmark dose at 10% (BMDL10) was 10 μg/kg body weight (bw) per day, derived from the incidence of rat liver tumours (benign and malignant) induced by NDEA and used in a margin of exposure (MOE) approach. Analytical results on the occurrence of N-NAs were extracted from the EFSA occurrence database (n = 2,817) and the literature (n = 4,003). Occurrence data were available for five food categories across TCNAs. Dietary exposure was assessed for two scenarios, excluding (scenario 1) and including (scenario 2) cooked unprocessed meat and fish. TCNAs exposure ranged from 0 to 208.9 ng/kg bw per day across surveys, age groups and scenarios. 'Meat and meat products' is the main food category contributing to TCNA exposure. MOEs ranged from 3,337 to 48 at the P95 exposure excluding some infant surveys with P95 exposure equal to zero. Two major uncertainties were (i) the high number of left censored data and (ii) the lack of data on important food categories. The CONTAM Panel concluded that the MOE for TCNAs at the P95 exposure is highly likely (98-100% certain) to be less than 10,000 for all age groups, which raises a health concern.

A transcriptomic analysis based on aberrant methylation levels revealed potential novel therapeutic targets for nasopharyngeal carcinoma

Background

This study aimed to identify potential novel therapeutic targets for nasopharyngeal carcinoma (NPC) by identifying aberrantly methylated-differentially expressed genes (DEGs) and pathways based on a comprehensive bioinformatics analysis.

Methods

Eight gene expression data sets and 2 methylation microarray data sets that included NPC and control groups from the Gene Expression Omnibus were identified. Meta-analyses of the DEGs were performed using the online analysis database “NetworkAnalyst”. Aberrantly methylated gene loci were obtained from the GEO2R. Aberrantly methylated DEGs were obtained from Venn diagrams. The enrichment analysis was carried out on the “Metascape” website, and the protein-protein interaction (PPI) network construction, network analysis, and visualization of the analysis results were carried out on the “String” website using “Cytoscape” software.

Results

In total, 544 hypomethylation high-expression genes and 164 hypermethylation low-expression genes were obtained. The enrichment and PPI network analyses suggested that several pathways and hub genes with abnormal gene expression accompanied by methylation change, including inositol-trisphosphate 3-kinase B (ITPKB), G protein subunit beta 5 (GNB5), FYN proto-oncogene, Src family tyrosine kinase (FYN), LCK proto-oncogene, Src family tyrosine kinase (LCK), nuclear factor of activated T cells 1 (NFATC1), GNAS complex locus (GNAS), protein kinase C beta (PRKCB), zeta chain of T cell receptor associated protein kinase 70 (ZAP70), lysophosphatidic acid receptor 1 (LPAR1), protein kinase C epsilon (PRKCE), tumor protein p53 (TP53), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), fibronectin 1 (FN1), cyclin D1 (CCND1), vascular endothelial growth factor A (VEGFA), HRas proto-oncogene, GTPase (HRAS), signal transducer and activator of transcription 3 (STAT3), fibroblast growth factor 2 (FGF2), amyloid beta precursor protein (APP), and matrix metallopeptidase 2 (MMP2), may be related to the occurrence of nasopharyngeal carcinoma .

Conclusions

The identification of novel and important pathways and hub genes and their roles in the occurrence and development of NPC will guide clinical research and the development of pharmaceutical targets.

Baicalein Inhibits Metastatic Phenotypes in Nasopharyngeal Carcinoma Cells via a Focal Adhesion Protein Integrin β8

Baicalein, a prominent flavonoid from the indigenous herbal plant Scutellaria baicalensis Georgi, possesses broad-spectrum anticancer activities. However, the biological effects of baicalein on nasopharyngeal carcinoma (NPC) and its underlying mechanisms remain unclarified. Thus, in this study, we examined the effects of baicalein on NPC cell lines and investigated the corresponding molecular mechanism through transcriptome profiling. In the study, four NPC cell lines were treated with various concentrations of baicalein at different time points. Cellular toxicity and proliferative inhibition of baicalein were examined by MTT assay. Metastatic phenotypes of NPC cells were investigated by wound healing, transwell, and adhesion assays. Additionally, microarray experiments were performed to determine the cellular pathways affected by baicalein. The expression and localization of the integrin β8 were validated by western immunoblotting and immunofluorescence. Our results revealed that baicalein exhibited its cytotoxicity and antiproliferative activity on all tested NPC cell lines. It also significantly inhibited metastatic phenotypes at sub-lethal concentrations. Transcriptomic analysis showed that baicalein significantly affected the focal adhesion pathway in NPC, where integrin β8 was greatly diminished. Thus, the present study results suggested that baicalein inhibits the metastatic phenotypes of NPC cells by modulating integrin β8, one of the major molecules in a focal adhesion pathway.

Combination of Epithelial Growth Factor Receptor Blockers and CDK4/6 Inhibitor for Nasopharyngeal Carcinoma Treatment

Simple Summary

Our findings indicated that the EGF-EGFR pathway was highly activated in very young patients with recurrent or metastatic NPC. High EGFR expression in patients with metastatic NPC resulted in poor clinical outcomes. To examine whether the EGFR pathway serves as a therapeutic target for NPC, NPC patient-derived xenograft (PDX) and NPC cell lines were treated with EGFR inhibitors (EGFRi) and a cell cycle blocker. Either EGFRi or cell cycle blocker treatment alone could reduce NPC cell growth and PDX tumor growth. Furthermore, combination treatment exerted an additive suppression effect on PDX tumor growth. This study provides promising evidence that EGFRi used in combination with a cell cycle blocker may be used to treat patients with NPC.

Abstract

Background: Nasopharyngeal carcinoma (NPC) involves host genetics, environmental and viral factors. In clinical observations, patients of young and old ages were found to have higher recurrence and metastatic rates. Methods: Cytokine array was employed to screen druggable target(s). The candidate target(s) were confirmed through patient-derived xenografts (PDXs) and a new EBV-positive cell line, NPC-B13. Results: Overexpression of epithelial growth factor (EGF) and EGF receptor (EGFR) was detected in young patients than in older patients. The growth of NPC PDX tumors and cell lines was inhibited by EGFR inhibitors (EGFRi) cetuximab and afatinib when used separately or in combination with the cell cycle blocker palbociclib. Western blot analysis of these drug-treated PDXs demonstrated that the blockade of the EGF signaling pathway was associated with a decrease in the p-EGFR level and reduction in PDX tumor size. RNA sequencing results of PDX tumors elucidated that cell cycle-related pathways were suppressed in response to drug treatments. High EGFR expression (IHC score ≥ grade 3) was correlated with poor survival in metastatic patients (p = 0.008). Conclusions: Our results provide encouraging preliminary data related to the combination treatment of EGFRi and palbociclib in patients with NPC.

Rare tumors: Retinoblastoma, nasopharyngeal cancer, and adrenocorticoid tumors

The role of surgery, chemotherapy, and radiation therapy for retinoblastoma has evolved considerably over the years with the efficacy of intraarterial chemotherapy and the high incidence of secondary malignant neoplasms following radiation therapy. The use of spot scanning intensity-modulated proton therapy may reduce the risk of secondary malignancies. For pediatric nasopharyngeal carcinoma, the current standard of care is induction chemotherapy followed by chemoradiation therapy. For adrenocortical carcinoma, the mainstay of treatment is surgery and chemotherapy. The role of radiation therapy remains to be defined.

Identification of key pseudogenes in nasopharyngeal carcinoma based on RNA-Seq analysis

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a malignant head and neck tumor, and more than 70% of new cases are in East and Southeast Asia. However, association between NPC and pseudogenes playing important roles in genesis of multiple tumor types is still not clear and needs to be investigated.

METHODS

Using RNA-Sequencing (RNA-seq) technology, we analyzed pseudogene expression in 13 primary NPC and 6 recurrent NPC samples as well as their paracancerous counterparts. Quantitative PCR was used to validate the differentially expressed pseudogenes.

RESULTS

We found 251 differentially expressed pseudogenes including 73 up-regulated and 178 down-regulated ones between primary NPC and paracancerous tissues. Enrichment analysis of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were conducted to filter out the key pseudogenes. We reported that pseudogenes from cytochrome P450 (CYP) family, such as CYP2F2P, CYP2G1P, CYP4F24P, CYP2B7P and CYP2G2P were significantly down-regulated in NPC compared to paracancerous tissues, while IGHV1OR15-2, IGHV3-11, FCGR1CP and IGHV3-69-1 belonging to Fc gamma receptors were significantly up-regulated. CYP2B7P, CYP2F2P and CYP4F26P were enriched in arachidonic acid metabolism pathway. The qRT-PCR analysis validated the lower expression of pseudogenes CYP2F2P and CYP2B7P in NPC tissues and cell lines compared to paracancerous tissues and normal human nasopharyngeal epithelial cell line. CYP2B7P overexpression weakened migratory and invasive capacity of NPC cell line. Moreover, the expression pattern of those pseudogenes in recurrent NPC tissues was different from the primary NPC.

CONCLUSION

This study suggested the role of pseudogenes in tumorigenesis and progression, potentially functioning as therapeutic targets to NPC.

Epidemiology of Virus Infection and Human Cancer

Seven viruses including the Epstein-Barr virus (EBV), hepatitis B virus (HBV), hepatitis C virus (HCV), Kaposi's sarcoma herpes virus (KSHV), human immunodeficiency virus, type-1 (HIV-1), human T cell lymphotrophic virus, type-1 (HTLV-1), and human papillomavirus (HPV) have been classified as Group 1 human carcinogens by the International Agency for Research on Cancer (IARC). The conclusions are based on the findings of epidemiological and mechanistic studies. EBV, HPV, HTLV-1, and KSHV are direct carcinogens; HBV and HCV are indirect carcinogens through chronic inflammation; and HIV-1 is an indirect carcinogen through immune suppression. Some viruses may cause more than one cancer, while some cancers may be caused by more than one virus. However, only a proportion of persons infected by these oncogenic viruses will develop specific cancers. A series of studies have been carried out to assess the viral, host, and environmental cofactors of EBV-associated nasopharyngeal carcinoma, HBV/HCV-associated hepatocellular carcinoma, and HPV-associated cervical carcinoma. Persistent infection, high viral load, and viral genotype are important risk predictors of these virus-caused cancers. Risk calculators incorporating host and viral risk predictors have been developed for the prediction of long-term risk of hepatocellular carcinoma, nasopharyngeal carcinoma and cervical cancer. These risk calculators are useful for the triage and clinical management of infected patients. Both clinical trials and national programs of immunization, antiviral therapy and screening have demonstrated a significant reduction in the incidence of cancers caused by HBV, HCV, and HPV. Future research on gene-gene and gene-environment interactions of oncogenic viruses and the human host using large-scale longitudinal studies with serial measurements of biosignatures are in urgent need.

Circulating Epstein-Barr virus microRNA profile reveals novel biomarker for nasopharyngeal carcinoma diagnosis

Nasopharyngeal carcinoma (NPC), a tumor quite prevalent in Asia, is closely associated with Epstein-Barr virus (EBV) infection status. Many NPC patients are not able to be treated in time when being diagnosed at an advanced stage. EBV-encoded microRNAs are reliable sources of biomarkers for NPC diagnosis. In this study, we conducted circulating EBV microRNAs profiling by quantitative reverse transcription polymerase chain reaction (qRT-PCR) among plasma samples of 159 NPC patients versus 145 normal controls (NCs) and serum samples of 60 NPC patients versus 60 NCs. Among the 44 mature EBV-encoded miRNAs, only miR-BART19-3p in plasma was proved to be significantly up-regulated in NPC patients (P< 0.05; fold change (FC) > 2.0). The area under the receiver operating characteristic curve (AUC) for the signature to discriminate NPC patients from NCs was 0.848 with the sensitivity and specificity being 71.7% and 72.3%, respectively. The identified biomarker was analyzed in tissue specimens (44 NPC VS. 32 NCs) and proved to be consistently up-regulated in NPC tumor tissues. Bioinformatics analysis was further conducted to predict the potential targets of miR-BART-19-3p, which provided some hints to its close relationship with NPC development. In conclusion, we identified a novel biomarker - plasma miR-BART19-3p for the detection of NPC.

Fucoxanthin treatment inhibits nasopharyngeal carcinoma cell proliferation through induction of autophagy mechanism

Nasopharyngeal carcinoma (NPC) arises from the epithelium of the nasopharyngeal mucosa. Elderly people above the age of 65 years are more susceptible to NPC. Nasopharyngectomy is the renowned treatment procedure to NPC; however, it is too risky due to its complicated surgical procedure. Other treatment methods also reported with serious side effects such brain injury; hence, the alternative anticancer drug without any side effects was needed. Fucoxanthin is a carotenoid derived from marine algae with the numerous pharmacological functions. This study aims to examine the inhibitory potential in NPC cell proliferation via apoptosis and autophagy. The cytotoxicity of fucoxanthin on C666-1 cells was observed by the MTT assay. The expression of autophagy-linked proteins was assessed with immunoblotting analysis. The expression of autophagy protein LC3 was estimated using immunocytochemical analysis in C666-1 and GFP-LC3 transfected cells. Furthermore, the fucoxanthin-treated C666-1 cells were analyzed with TUNEL assay. The apoptotic level in the fucoxanthin-treated C666-1 cells was evaluated using acridine orange staining. Fucoxanthin significantly increased the expression of autophagy-linked proteins which is clearly depicted in the immunoblotting analysis and immunocytochemical analysis of GFP-tagged LC3 protein. The results of TUNEL assay of fucoxanthin-treated C666-1 in the presence autophagy inhibitors demonstrated the induction of autophagy by fucoxanthin. Acridine orange staining results of C666-1 confirmed fucoxanthin decreases the expression of autophagy-linked proteins during stressed condition thereby causes apoptosis. Our overall results authentically conclude that fucoxanthin induces autophagy and apoptosis in NPC cell line, and it can be ideal agent to treat nasopharyngeal cancer in future with further investigations.

Risk factors for Epstein Barr virus-associated cancers: a systematic review, critical appraisal, and mapping of the epidemiological evidence

BACKGROUND

Epstein Barr Virus (EBV) infects 90%-95% of all adults globally and causes ~ 1% of all cancers. Differing proportions of Burkitt's lymphoma (BL), gastric carcinoma (GC), Hodgkin's lymphoma (HL) and nasopharyngeal carcinoma (NPC) are associated with EBV. We sought to systematically review the global epidemiological evidence for risk factors that (in addition to EBV) contribute to the development of the EBV-associated forms of these cancers, assess the quality of the evidence, and compare and contrast the cancers.

METHODS

MEDLINE, Embase and Web of Science were searched for studies of risk factors for EBV-associated BL, GC, HL and NPC without language or temporal restrictions. Studies were excluded if there was no cancer-free comparator group or where analyses of risk factors were inadequately documented. After screening and reference list searching, data were extracted into standardised spreadsheets and quality assessed. Due to heterogeneity, a narrative synthesis was undertaken.

RESULTS

9916 hits were retrieved. 271 papers were retained: two BL, 24 HL, one GC and 244 NPC. The majority of studies were from China, North America and Western Europe. Risk factors were categorised as dietary, environmental/non-dietary, human genetic, and infection and clinical. Anti-EBV antibody load was associated with EBV-associated GC and BL. Although the evidence could be inconsistent, HLA-A alleles, smoking, infectious mononucleosis and potentially other infections were risk factors for EBV-associated HL. Rancid dairy products; anti-EBV antibody and EBV DNA load; history of chronic ear, nose and/or throat conditions; herbal medicine use; family history; and human genetics were risk factors for NPC. Fresh fruit and vegetable and tea consumption may be protective against NPC.

CONCLUSIONS

Many epidemiological studies of risk factors in addition to EBV for the EBV-associated forms of BL, GC, HL and NPC have been undertaken, but there is a dearth of evidence for GC and BL. Available evidence is of variable quality. The aetiology of EBV-associated cancers likely results from a complex intersection of genetic, clinical, environmental and dietary factors, which is difficult to assess with observational studies. Large, carefully designed, studies need to be strategically undertaken to harmonise and clarify the evidence.

REGISTRATION

PROSPERO CRD42017059806.

Inhibition of HMGB1 Overcomes Resistance to Radiation and Chemotherapy in Nasopharyngeal Carcinoma

Objective

This study aimed to investigate the effect of high mobility group protein B1 (HMGB1) on chemoresistance and radioresistance in nasopharyngeal carcinoma (NPC).

Materials and Methods

HMGB1-knockout HK1 cell lines were generated using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system. Western blotting was used to evaluate the protein expression level of HMGB1. DNA repair efficiency of non-homologous end joining (NHEJ) and homologous recombination (HR) was monitored through NHEJ and HR reporter assay. Cellular protein–protein interaction between HMGB1 and NHEJ apparatus was determined by immunoprecipitation. Direct protein–protein interaction was examined by affinity capture assay with purified protein. Protein-DNA binding was evaluated by chromatin fractionation assay. Cell viability assay was employed to measure cell sensitivity to ionizing radiation (IR) or cisplatin.

Results

HMGB1-knockout NPC cells showed significant decrease in NHEJ efficiency. HMGB1 immunoprecipitated NHEJ key factors in NPC cells and promoted DNA-binding activity of Ku70. Mutational analysis revealed that serine 155 of Ku70 was required for its direct interaction with HMGB1. HMGB1 was highly expressed in radio- and chemoresistant NPC cells. Deficiency of HMGB1 sensitized wild-type (WT) and resistant NPC cells to IR and cisplatin. Glycyrrhizin, which is HMGB1 inhibitor, impaired DNA binding of HMGB1 and exhibited excellent synergy with IR and cisplatin.

Conclusion

HMGB1 promotes NHEJ via interaction with Ku70 resulting in resistance to IR and cisplatin. Inhibition of HMGB1 by glycyrrhizin is a potential therapeutic regimen to treat cisplatin and IR resistant NPC patients.

Association of Ambient Air Pollution with Nasopharyngeal Carcinoma Incidence in Ten Large Chinese Cities, 2006-2013

Large cities in China are experiencing severe ambient air pollution. Although China accounts for more than 45% of new cases of nasopharyngeal carcinoma worldwide in 2018, few studies have examined the association between ambient air pollution and the high nasopharyngeal carcinoma (NPC) incidence in China. Thus, we aim to investigate whether exposure to ambient air pollution (including nitrogen dioxide, sulfur dioxide, and PM10) would significantly affect NPC incidence in large Chinese cities. We collected panel data of ten Chinese provincial cities about local NPC incidence, air pollution level, meteorology, and city profiles during 2006 to 2013 to construct a two-way fixed-effects model to explore the association between ambient air pollution and NPC incidence, as well as possible regional and gender differences behind the association. We found that NO2 had the strongest association with NPC incidence, and the relative risks were 2.2995 (95% CI, 1.2567-4.2075) for males and 1.3010 (95% CI, 0.8212-2.0620) for females, respectively. Under cumulative exposure, it was still NO2 that had the strongest association with NPC incidence, with a relative risk of 1.8836 (95% CI, 1.2416-2.8577), compared to 1.0857 (95% CI, 0.9474-1.2450) and 1.0547 (95% CI, 0.8790-1.2663) for SO2 and PM10, respectively. In addition, males were found more sensitive to ambient air pollution than females. We also found that southern Chinese cities were more sensitive to NO2 than northern cities, which might be related to a higher humidity there. Our study reveals that exposure to ambient air pollutants like SO2, PM10, and particularly NO2, is significantly positively associated with NPC incidence in China.

Wood dust exposure and risks of nasopharyngeal carcinoma: a meta-analysis

Background

Wood dust has been confirmed as one kind of human carcinogen. However, there are inconsistent study results of exploring the relationship of exposure to wood dust and occurrence of nasopharyngeal cancer (NPC). For a greater clarification, the authors systemically reviewed the relevant published articles on the relationship of exposure to wood dust and occurrence of NPC. And meta-analysis was conducted.

Methods

The databases of PubMed, U.S. National Library of Medicine (MEDLINE), Embase and Science Direct were searched for the relevant publications. And Newcastle-Ottawa scale was employed for judging the quality of articles. Random-effect model was utilized for meta-analysis.

Results

Among a total of 583 retrieved items, 10 case–control studies and 1 cohort study were selected. The ratio of maximal/minimal exposure concentration of wood dust yielded a pooled odd ratio (OR) of 2.18 (95% CI = 1.62–2.93, P = 0.063) with a moderate heterogeneity (I2: 43.0%; P = 0.001). And subgroup analysis was performed for such factors as exposure status, exposure population and geographic region. No publishing bias was noted. Exposing to a high concentration of wood dust was positively proportional to occurring risk of NPC.

Conclusion

It hints at the contributing effect of wood dust upon NPC. For eliminating the effects of other confounding factors, larger prospective cohort studies are required for further elucidating the relationship of exposure to wood dust and occurrence of NPC.

Cigarette smoking increases the risk of nasopharyngeal carcinoma through the elevated level of IgA antibody against Epstein-Barr virus capsid antigen: A mediation analysis

Background

The study aims are to evaluate the associations between nasopharyngeal carcinoma (NPC) risk and cigarette smoking and to explore the effects of cigarette smoking on Epstein‐Barr virus (EBV) infection for NPC risk.

Methods

1235 male NPC cases and 1262 hospital‐based male controls matched to cases were recruited across six collaborative hospitals between 2010 and 2014. Using a standardized questionnaire, information on cigarette smoking and other potential risk factors for NPC was obtained. Blood was collected and used for anti‐EBV VCA IgA and anti‐EBV EA‐EBNA1 IgA testing using standard methods. Unconditional logistic regression analysis was used to estimate odds ratio (OR) with 95% confidence interval (CI) for each risk factor after adjusting for confounders.

Results

63.6% of cases and 44.0% of controls reported ever smoking cigarettes. After full adjustment, current smokers had a significant 1.60‐fold (95% CI = 1.30‐1.97) and former smokers a borderline significant 1.27‐fold (95% CI = 1.00‐1.60) increased NPC risk compared to never smokers. NPC risk increased with increasing duration, intensity, and pack‐years of cigarette smoking but not with age at smoking initiation. Among controls, anti‐EBV VCA IgA seropositivity rate was higher in current smokers than never smokers (14.0% vs 8.4%; OR = 1.82; 95% CI = 1.19‐2.79). Mediation analyses showed that more than 90% of the cigarette smoking effect on NPC risk is mediated through anti‐EBV VCA IgA.

Conclusion

This study confirms the association between long‐term cigarette smoking and NPC and demonstrates that current smoking is associated with seropositivity of anti‐EBV VCA IgA antibodies.

Pinostilbene Hydrate Inhibits the Migration and Invasion of Human Nasopharyngeal Carcinoma Cells by Downregulating MMP-2 Expression and Suppressing Epithelial-Mesenchymal Transition Through the Mitogen-Activated Protein Kinase Signaling Pathways

Background: Nasopharyngeal carcinoma (NPC) is one of the most common head and neck cancers in East and Southeast Asia. During the past decades, advances in radiotherapy and chemotherapy had shown the improvement in tumor control with fewer side effects. Nevertheless, metastasis of NPC causes treatment failure and is often associated with poor clinical outcome and cancer mortality.

Hypothesis/Purpose: Pinostilbene hydrate (PSH) was recently demonstrated to have anti-metastatic properties on human oral cancers. However, the effects of PSH on NPC cells remain unknown.

Methods and Results: This study aims to investigate the anti-cancer ability of PSH on human NPC by wound healing, transwell assays, zymography assay, and Western blot assay to explore the possible underlying mechanisms. PSH significantly reduced the migrated distance of NPC cells in a dose-dependent manner and the abilities of cancer cell migration and invasion were markedly inhibited. The activity and the expression of MMP-2 were also significantly decreased after treatment with PSH. Furthermore, combined treatment of PSH with ERK1/2 inhibitor (U0126) caused significant elevation of the activity and the expression of MMP-2. Additionally, PSH upregulated the expression levels of E-cadherin and Claudin-1 while downregulating that of N-cadherin and vimentin on both NPC cell lines.

Conclusion: Our research illustrates that PSH inhibits the migration and invasion of human NPC cells. After exposure to PSH on NPC, the expression of MMP-2 is downregulated and EMT is suppressed through MAPK signaling pathways. These observations suggest that PSH could be a potential anti-metastatic agent for patients with NPC.

Past and Recent Salted Fish and Preserved Food Intakes Are Weakly Associated with Nasopharyngeal Carcinoma Risk in Adults in Southern China

BACKGROUND

Chinese-style salted fish intake in early life is considered an established risk factor for nasopharyngeal carcinoma (NPC). However, results for adult intakes of salted fish and preserved foods are inconsistent.

OBJECTIVE

The aim of this study was to ascertain the relations of Chinese-style hard and soft salted fish and preserved food intakes with NPC risk.

METHODS

We conducted a population-based case-control study in southern China with 2554 NPC cases identified through a rapid case ascertainment system and 2648 healthy controls, frequency-matched on age, sex, and area. Subjects (aged 20-74 y) were interviewed via a food-frequency questionnaire, including information on portion size. Data were also collected on alcohol consumption and potential confounders. Food intake was grouped into 3-5 energy-adjusted intake levels during adulthood (10 y prior) and adolescence (16-18 y). For childhood (at age 10 y), intake frequency of selected food items was collected. Multivariate-adjusted ORs with 95% CIs were estimated via logistic regression.

RESULTS

We found no association between NPC and intake of hard Chinese-style salted fish during adulthood, and an increased risk at the highest level of intake during adolescence (OR: 1.19; 95% CI: 1.03, 1.39). In contrast, we found a decreased risk for the middle intake level of soft salted fish during adulthood (OR: 0.68; 95% CI: 0.57, 0.81) and adolescence (OR: 0.71; 95% CI: 0.59, 0.85). Preserved foods showed contrasting risk profiles, e.g., the highest adult intake level of salted egg (OR: 1.51; 95% CI: 1.22, 1.87) and fermented black beans (OR: 0.67; 95% CI: 0.56, 0.80). Associations with NPC were weaker than previously reported, e.g., for weekly childhood intake of salted fish (OR: 1.56; 95% CI: 1.24, 1.97).

CONCLUSIONS

Hard and soft salted fish have different risk profiles. Salted fish and other preserved foods were at most weak risk factors for NPC in all periods and may play a smaller role in NPC occurrence than previously thought.

Third Epidemiological Analysis of Nasopharyngeal Carcinoma in the Central Region of Japan from 2006 to 2015

The present study aimed to clarify the incidence and clinical outcomes of nasopharyngeal carcinoma (NPC) in the Chubu region of Japan from 2006 to 2015, compared with previous reports. A retrospective analysis was conducted based on medical records from 40 hospitals located in the Chubu region in the central Japanese main island, with a population of around 22.66 million individuals. This study was designed in line with to two previous clinical studies into NPC conducted in the same area of Japan. We recruited NPC patients diagnosed in hospitals across this area over a 10-year period (2006–2015) using a questionnaire about sex, age, primary site, clinical symptoms, pathology, Union for International Cancer Control (UICC) staging, serological exam, treatment, and survival. A total of 620 NPC patients were identified. The age-standardized incidence of NPC from 2006 to 2015 was 0.27 per 100,000 individuals per year. There were no significant differences between this study and the previous two studies conducted in the same area of Japan. The five-year overall survival rate for all patients was 75.9%, while those for patients with stages I, II, III, and IVA were 97%, 91%, 79%, and 68%, respectively. The age-standardized annual incidence of NPC in the present study was 0.27 per 100,000 individuals per year, which was relatively low and stable. The five-year overall survival rate for all NPC patients was significantly improved in this decade compared with previous studies. The smoking rates in male and female NPC patients were 64.5% and 18.8%, respectively, thereby suggesting the involvement of smoking in the incidence of NPC.

High SRC-1 and Twist1 expression predicts poor prognosis and promotes migration and invasion by inducing epithelial-mesenchymal transition in human nasopharyngeal carcinoma

Steroid receptor coactivator 1 (Src-1) and Twist1 are aberrantly upregulated in a variety of tumors and play an important role in tumor progression. However, the exact role of Src-1 and Twist1 in nasopharyngeal carcinoma (NPC) is uncertain. In this study, we investigated the possible prognostic value and biological effect of Src-1 and Twist1 in NPC. Src-1 and Twist1 expression was detected in a cohort of NPC patients (n = 134) by qRT-PCR. Kaplan-Meier survival analysis was used comparing overall survival (OS) and progression-free survival (PFS). Multivariate analysis was performed using the Cox proportional hazard regression model. Biologic effect of Src-1 and Twist1 in NPC cell lines was evaluated by western blot, colony formation assay, soft agar assay, scratch wound healing assay, transwell invasion assay and tumor xenografts growth. We have found that Src-1 and Twist1 were aberrantly upregulated in human NPC tissues, and associated with advanced tumor stage, distant metastasis and unfavorable prognosis. Knockdown of Src-1 or Twist1 in human NPC cell line CNE-1 suppressed colony formation, anchorage-independent growth, cell migration, invasion and tumor xenografts growth, while enforced expression of Src-1 or Twist1 in human NPC cell line HNE-2 promotes anchorage-independent growth, cell migration and invasion. In addition, Src-1 and Twist1 could suppress E-cadherin expression and increase Vimentin expression, thus suggested that Src-1 and Twist1 enhanced the malignant behaviors of NPC cells via inducing epithelial-mesenchymal transition (EMT). Our data indicated that Src-1 and Twist1 could be possible prognostic biomarkers and potential therapy targets for patients with NPC.

Occupational exposure to wood dust and risk of nasopharyngeal cancer: A systematic review and meta-analysis

INTRODUCTION

Nasopharyngeal cancer (NPC) is one of the most commonly occurring cancers in some regions. While wood dust is a confirmed human carcinogen, its association with NPC remains uncertain due to inconsistent findings in the related studies. We performed the first systematic review and meta-analysis on the epidemiological evidence to examine the association between occupational exposure to wood dust and the risk of NPC.

METHODS

In this meta-analysis study, the PubMed and Scopus databases were searched for English-language publications. seven case-control studies were included in the pooled analysis.

RESULTS

These studies were published between 1991 and 2016. The heterogeneity across the studies was significant (P = 0.06, I² = 50.4%). The results of the random effects model meta-analysis showed that there was a direct relationship between occupational exposure to wood dust and NPC (OR = 1.5 95% CI: 1.09-2.07). Among different histological subtypes of NPC, there was a significantly increased risk for the nonkeratinizing carcinoma following wood dust exposure (OR = 1.68, 95%CI: 1.03-2.74). We found no evidence of publication bias across studies according to the result of the Egger's test (P of bias = 0.073).

CONCLUSIONS

This meta-analysis suggests that occupational exposure to wood dust can be associated with an increased risk of the nonkeratinizing carcinoma of the histological subtypes of nasopharyngeal cancer.

Smoking can increase nasopharyngeal carcinoma risk by repeatedly reactivating Epstein-Barr Virus: An analysis of a prospective study in southern China

Background

The association between smoking and nasopharyngeal carcinoma (NPC) is still uncertain. The aim of this study was to validate smoking effect on NPC and explore if smoking can induce NPC by persistently reactivating EBV in long‐term based on a prospective cohort design.

Methods

A NPC screening cohort with 10 181 eligible residents in Sihui city, southern China was conducted from 2008 to 2015. The smoking habit was investigated through the trained interviewers and EBV antibodies (VCA‐IgA, EBNA1‐IgA) as screening markers were tested periodically. New NPC cases were identified through local cancer registry. Cox's regression model was used to estimate the adjusted hazard ratios (aHRs) of smoking on NPC incidence. In the non‐NPC participants, the associations between smoking and EBV seropositivity in different periods were assessed by logistic regression and generalized estimating equations (GEE).

Results

With a median of 7.54 years, 71 NPCs were diagnosed ≥1 year after recruitment. Compared with never smokers, the aHRs of developing NPC among ever smokers were 3.00 (95%CI: 1.46‐6.16). Stratified by sex, the HRs of ever smoking were 2.59 (95%CI: 1.07‐6.23) for male and 3.75 (95%CI: 1.25‐11.20) for female, respectively. Among the non‐NPC individuals, ever smoking was not only associated with EBV seropositivity at baseline, but also in the 3‐5 years of follow up, with adjusted odds ratios (aORs) of 1.68 (95%CI: 1.29‐2.18) for VCA‐IgA and 1.92 (95%CI: 1.42‐2.59) for EBNA1‐IgA. Among the smokers who were tested EBV antibodies at least twice, the similar results were obtained using GEE.

Conclusion

Smoking could significantly increase the long‐term risk of NPC in southern China, partly by persistently reactivating EBV.

The identification of key genes in nasopharyngeal carcinoma by bioinformatics analysis of high-throughput data

Nasopharyngeal carcinoma (NPC) is a common pattern of regional malignancy in the south of China, especially in Guangdong province. The development of computerized tomography (CT) technology and the improvement of radiotherapy scheme can improve the survival rate of NPC patients. However, the prevalence and recurrence rate of NPC are increasing every year. It is urgent for us to uncover the molecular mechanism of NPC. In this study, we used scientific information retrieval from the GEO (gene expression omnibus) database to download the GSE12452, which contained 41 samples, including 31 nasopharyngeal carcinoma samples and 10 control samples. With the help of GO (gene ontology) analysis, KEGG (kyoto encyclopedia of genes and genomes) analysis, PPI (protein-protein interaction) network model construction, and WGCNA (weighted gene co-expression network analysis), we found 6896 differentially expressed genes, which affected the biological processes included cell cycle process, DNA metabolic process, DNA repairing, immune response, cell activation, regulation of immune system process, inflammatory response. The 20 hub genes present in front of us are SYK, PIK3CG, FYN, ACACB, LRRK2, RIPK4, RAC2, PIK3CD, PTPRC, LCR, RAD51, MAD2L1, CDK1, PCNA, GMPS, CCNB1, GAPDH, CCNA2, RFC4, TOP2A. In the future, these are the areas where we need to focus on the molecular mechanism of NPC.

Recent advances in the management of nasopharyngeal carcinoma

Over the last few years, certain areas in the management nasopharyngeal carcinoma (NPC) that have an impact on the care of these patients have evolved, particularly with regard to liquid biopsies, minimally invasive surgery, and advances in chemotherapy and immunotherapy. Beyond its proven role in the diagnostics, surveillance, and treatment of NPC, liquid biopsy with plasma Epstein–Barr virus DNA in the screening of high-risk populations for NPC is strongly supported by recent evidence. Surgery of the nasopharynx is reserved for locally recurrent NPC, and in recent years there have been great strides in minimally invasive techniques with survival rates similar to those of open techniques in treating NPC. Induction chemotherapy in a recent pooled analysis was shown to be superior to concurrent chemotherapy alone for locoregionally advanced NPC. Finally, immunotherapy with a PD-1 inhibitor in NPC has been shown to have 1-year overall survival rates comparable to those of other patients with heavily pre-treated metastatic or recurrent NPC. In this commentary, we discuss these recent advances and their potential in the clinical management of patients with NPC.

Assessment, mapping, and management of health risk from nitrate accumulation in onion for Iranian population

Excess accumulation of nitrate in vegetable crops is normally related to the excessive use of nitrogen fertilizers applied in agricultural fields. This study was performed to evaluate the level of nitrate concentration in onion production in Isfahan province of Iran and the potential health risks associated with high level of nitrate in this crop, as an example of a case-study. The risk was estimated by using the United States Environmental Protection Agency (USEPA) method and presented as risk maps. Additionally, the impact of an improved fertilizer management practice in selected vulnerable fields for reducing nitrate concentration in onion production was evaluated. For this assessment, four different onion fields in which onion bulb nitrate concentration was higher than the safety level (70 mg kg^-1 FW), provided by Welch (2003) in a survey study, were chosen. The risk maps showed that despite higher risk possibility in adults, in comparison with children, all values were lower than the acceptable level. Further, the split application of nitrogen fertilizers in all fields significantly reduced plant nitrate concentration with no reduction in yield and even observed increase in the overall economic yield production. Therefore, considering crop yields and nitrate accumulation impacts, improved nitrogen management could provide an opportunity to promote onion crop production while reducing negative health effects in high-risk regions in Isfahan province of Iran.

Increased risk of incident nasopharyngeal carcinoma with exposure to air pollution

Background

Nasopharyngeal carcinoma (NPC) is a race-specific malignancy. The nasal cavity is the main entry point for air pollutants or poisonous gases into the human body. However, the risk of NPC in populations exposed to air pollution remains unknown.

Methods

We combined data from the Taiwan Air Quality Monitoring Database (TAQMD) and the Longitudinal Health Insurance Database (LHID) to assess the risk of NPC in a population exposed to air pollution.

Results

Multivariate analysis revealed positive trends for the association between the risk of NPC and exposure to air pollution. After adjusting for potential covariates, the risk of developing NPC increased with the increase in nitrogen dioxide (NO₂) and fine particulate matter (PM_2.5) exposure concentrations from 1.39 to 2.28 and 2.01 to 1.97, respectively, compared to the risks at the lowest concentration levels.

Conclusions

We identified a significant risk of NPC in a population exposed to air pollution. However, this study had several limitations. Moreover, additional experimental and clinical studies on the associations between environmental factors and NPC risk are warranted.

Integrated genomic analyses in PDX model reveal a cyclin-dependent kinase inhibitor Palbociclib as a novel candidate drug for nasopharyngeal carcinoma

Background

Patient-derived xenograft (PDX) tumor model has become a new approach in identifying druggable tumor mutations, screening and evaluating personalized cancer drugs based on the mutated targets.

Methods

We established five nasopharyngeal carcinoma (NPC) PDXs in mouse model. Subsequently, whole-exome sequencing (WES) and genomic mutation analyses were performed to search for genetic alterations for new drug targets. Potential drugs were applied in two NPC PDX mice model to assess their anti-cancer activities. RNA sequencing and transcriptomic analysis were performed in one NPC PDX mice to correlate with the efficacy of the anti-cancer drugs.

Results

A relative high incident rate of copy number variations (CNVs) of cell cycle-associated genes. Among the five NPC-PDXs, three had cyclin D1 (CCND1) amplification while four had cyclin-dependent kinase inhibitor CDKN2A deletion. Furthermore, CCND1 overexpression was observed in > 90% FFPE clinical metastatic NPC tumors (87/91) and was associated with poor outcomes. CNV analysis disclosed that plasma CCND1/CDKN2A ratio is correlated with EBV DNA load in NPC patients’ plasma and could serve as a screening test to select potential CDK4/6 inhibitor treatment candidates. Based on our NPC PDX model and RNA sequencing, Palbociclib, a cyclin-dependent kinase inhibitor, proved to have anti-tumor effects by inducing G1 arrest. One NPC patient with liver metastatic was treated with Palbociclib, had stable disease response and a drop in Epstein Barr virus (EBV) EBV titer.

Conclusions

Our integrated information of sequencing-based genomic studies and tumor transcriptomes with drug treatment in NPC-PDX models provided guidelines for personalized precision treatments and revealed a cyclin-dependent kinase inhibitor Palbociclib as a novel candidate drug for NPC.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0873-5) contains supplementary material, which is available to authorized users.

Association of hOGG1 Ser326Cys, ITGA2 C807T, TNF-A -308G>A and XPD Lys751Gln polymorphisms with the survival of Malaysian NPC patients

Background

Nasopharyngeal carcinoma is a rare form of cancer across the world except in certain areas such as Southern China, Hong Kong and Malaysia. NPC is considered a relatively radiosensitive tumor and patients diagnosed at early stages tend to survive longer compared to those with advanced disease. Given that early symptoms of NPC are non-specific and that the nasopharynx is relatively inaccessible, less invasive screening methods such as biomarker screening might be the key to improve NPC survival and management. A number of genes with their respective polymorphisms have been shown in past studies to be associated with survival of various cancers. hOGG1 and XPD genes encode for a DNA glycosylase and a DNA helicase respectively; both are proteins that are involved in DNA repair. ITGA2 is the alpha subunit of the transmembrane receptor integrin and is mainly responsible for cell-cell and cell-extracellular matrix interaction. TNF-α is a cytokine that is released by immune cells during inflammation.

Methods

Restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) was used to genotype all the aforementioned gene polymorphisms. Kaplan-Meier survival function, log-rank test and Cox regression were used to investigate the effect of gene polymorphisms on the all-cause survival of NPC.

Results

NPC cases carrying T/T genotype of ITGA2 C807T have poorer all-cause survival compared to those with C/C genotypes, with an adjusted HR of 2.06 (95% CI = 1.14–3.72) in individual model. The 5-year survival rate of C/C carriers was 55% compared to those with C/T and T/T where the survival rates were 50% and 43%, respectively.

Conclusion

The finding from the present study showed that ITGA2 C807T polymorphism could be potentially useful as a prognostic biomarker for NPC. However, the prognostic value of ITGA2 C807T polymorphism has to be validated by well-designed further studies with larger patient numbers.

Test-retest reliability of a computer-assisted self-administered questionnaire on early life exposure in a nasopharyngeal carcinoma case-control study

We evaluated the reliability of early life nasopharyngeal carcinoma (NPC) aetiology factors in the questionnaire of an NPC case-control study in Hong Kong during 2014–2017. 140 subjects aged 18+ completed the same computer-assisted questionnaire twice, separated by at least 2 weeks. The questionnaire included most known NPC aetiology factors and the present analysis focused on early life exposure. Test-retest reliability of all the 285 questionnaire items was assessed in all subjects and in 5 subgroups defined by cases/controls, sex, time between 1^st and 2^nd questionnaire (2–29/≥30 weeks), education (secondary or less/postsecondary), and age (25–44/45–59/60+ years) at the first questionnaire. The reliability of items on dietary habits, body figure, skin tone and sun exposure in early life periods (age 6–12 and 13–18) was moderate-to-almost perfect, and most other items had fair-to-substantial reliability in all life periods (age 6–12, 13–18 and 19–30, and 10 years ago). Differences in reliability by strata of the 5 subgroups were only observed in a few items. This study is the first to report the reliability of an NPC questionnaire, and make the questionnaire available online. Overall, our questionnaire had acceptable reliability, suggesting that previous NPC study results on the same risk factors would have similar reliability.

Association between dietary nitrate and nitrite intake and sitespecific cancer risk: evidence from observational studies

Epidemiological studies have reported inconsistent findings on the association between dietary nitrate and nitrite intake and cancer risk. We performed a meta-analysis of epidemiological studies to summarize available evidence on the association between dietary nitrate and nitrite intake and cancer risk from published prospective and case-control studies. PubMed database was searched to identify eligible publications through April 30^th, 2016. Study-specific relative risks (RRs) with corresponding 95% confidence interval (CI) from individual studies were pooled by using random- or fixed- model, and heterogeneity and publication bias analyses were conducted.

Data from 62 observational studies, 49 studies for nitrates and 51 studies for nitrites, including a total of 60,627 cancer cases were analyzed. Comparing the highest vs. lowest levels, dietary nitrate intake was inversely associated with gastric cancer risk (RR = 0.78; 95%CI = 0.67-0.91) with moderate heterogeneity (I² = 42.3%). In contrast, dietary nitrite intake was positively associated with adult glioma and thyroid cancer risk with pooled RR of 1.21 (95%CI = 1.03-1.42) and 1.52 (95%CI = 1.12-2.05), respectively. No significant associations were found between dietary nitrate/nitrite and cancers of the breast, bladder, colorectal, esophagus, renal cell, non-Hodgkin lymphoma, ovarian, and pancreas. The present meta-analysis provided modest evidence that positive associations of dietary nitrate and negative associations of dietary nitrite with certain cancers.

Seroprevalence of IgA anti Epstein-Barr virus is high among family members of nasopharyngeal cancer patients and individuals presenting with chronic complaints in head and neck area

Epstein-Barr (EBV) infection and presence of a nasopharyngeal cancer (NPC) case in the family increases the risk of developing NPC. Aberrant anti-EBV immunoglobulin A (IgA) antibodies (EBV-IgA) may be present in the sera of non-cancer individuals and predict NPC. Limited studies report the presence of EBV-IgA antibodies within non-cancer individuals in Indonesia where the disease is prevalent. This study aimed at exploring whether EBV-IgA was found more frequently among first degree relatives of NPC patients and individuals presenting with chronic symptoms in the head and neck area compared to healthy controls. A total of 967 non-cancer subjects were recruited, including 509 family members of NPC cases, 196 individuals having chronic complaints in the head and neck region, and 262 healthy donors of the local blood bank. Sera were analyzed using a standardized peptide-based EBV-IgA ELISA. Overall, 61.6% of all individuals had anti-EBV IgA reactivity equal to or below cut off value (CoV). Seroreactivity above CoV was significantly higher in females (38.7%) compared to males (28.7%) (p = 0.001). Older individuals had more seroreactivity above CoV (42.5%) than the younger ones (26.4%) (p< 0.001). Seroprevalence was significantly higher in family members of NPC patients (41.7%), compared to 32.7% of individuals with chronic head and neck problems (p = 0.028) and 16.4% healthy blood donors (p< 0.001). As conclusion, this study showed a significant higher seroprevalence in healthy family members of NPC cases and subjects presenting with chronic symptoms in the head and neck area compared to healthy individuals from the general community. This finding indicates that both groups have elevated risk of developing NPC and may serve as targets for a regional NPC screening program.

Quantification of familial risk of nasopharyngeal carcinoma in a high-incidence area

BACKGROUND

To the authors' knowledge, no studies to date have explored familial risks of nasopharyngeal carcinoma (NPC) in detail and quantified its lifetime risk in high-incidence populations.

METHODS

The authors conducted a population-based case-control study of 2499 NPC cases and 2576 controls randomly selected in southern China from 2010 through 2014. Unconditional logistic regression was used to estimate multivariable-adjusted odds ratios (ORs) with 95% confidence intervals (95% CIs) associated with a family history of NPC. In addition, the authors compiled a reconstructed cohort comprising 40,781 first-degree relatives of cases and controls to calculate the lifetime cumulative risk of NPC.

RESULTS

Individuals with a first-degree family history of NPC were found to be at a >4-fold risk of NPC (OR, 4.6; 95% CI, 3.5-6.1) compared with those without such a history, but had no excess risk of other malignancies. The excess risk was higher for a maternal than a paternal history and was slightly stronger for a sibling compared with a parental history, and for a sororal than a fraternal history. Among relatives of cases, the cumulative risk of NPC up to age 74 years was 3.7% (95% CI, 3.3%-4.2%), whereas that among relatives of controls was 0.9% (95% CI, 0.7%-1.2%). Cumulative risk was higher in siblings than in parents among relatives of cases, whereas no such difference was noted among relatives of controls.

CONCLUSIONS

Individuals with a family history of NPC have a substantially higher risk of NPC. These relative and cumulative risk estimates can guide the development of strategies for early detection and clinical consultation in populations with a high incidence of NPC. Cancer 2017;123:2716-25. © 2017 American Cancer Society.

Elevated urinary levels of carcinogenic N-nitrosamines in patients with urinary tract infections measured by isotope dilution online SPE LC-MS/MS

N-nitrosamines (NAms) are well-documented for their carcinogenic potential. Human exposure to NAms may arise from the daily environment and endogenous formation via the reaction of secondary amines with nitrites or from bacteria infection. We describe the use of isotope dilution online solid-phase extraction (SPE) LC-MS/MS to quantify nine NAms in human urine. This method was validated and further applied to healthy subjects and patients with urinary tract infection (UTI). N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPYR) and N-nitrosomorpholine (NMOR) were analyzed with an APCI source, while N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), N-nitrosodi-n-propylamine (NDPA), N-nitrosodibutylamine (NDBA) and N-nitrosodiphenylamine (NDPhA) were quantified with an ESI source, due to their effect on the sensitivity and chromatography. NDMA was the most abundant N-nitrosamine, while NDPhA was firstly identified in human. UTI patients had three to twelve-fold higher concentrations for NDMA, NPIP, NDEA, NMOR and NDBA in urine than healthy subjects, and the NAms were significantly decreased after antibiotics treatment. NDMA concentrations were also significantly correlated with the pH value, leukocyte esterase activity or nitrite in urines of UTI patients. Our findings by online SPE LC-MS/MS method evidenced that UTI patients experienced various NAms exposures, especially the potent carcinogen NDMA, which was likely induced by bacteria infection.

Partial Least Square Discriminant Analysis Discovered a Dietary Pattern Inversely Associated with Nasopharyngeal Carcinoma Risk

Evidence on the association between dietary component, dietary pattern and nasopharyngeal carcinoma (NPC) is scarce. A major challenge is the high degree of correlation among dietary constituents. We aimed to identify dietary pattern associated with NPC and to illustrate the dose-response relationship between the identified dietary pattern scores and the risk of NPC. Taking advantage of a matched NPC case–control study, data from a total of 319 incident cases and 319 matched controls were analyzed. Dietary pattern was derived employing partial least square discriminant analysis (PLS-DA) performed on energy-adjusted food frequencies derived from a 66-item food-frequency questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated with multiple conditional logistic regression models, linking pattern scores and NPC risk. A high score of the PLS-DA derived pattern was characterized by high intakes of fruits, milk, fresh fish, vegetables, tea, and eggs ordered by loading values. We observed that one unit increase in the scores was associated with a significantly lower risk of NPC (OR_adj = 0.73, 95% CI = 0.60–0.88) after controlling for potential confounders. Similar results were observed among Epstein-Barr virus seropositive subjects. An NPC protective diet is indicated with more phytonutrient-rich plant foods (fruits, vegetables), milk, other protein-rich foods (in particular fresh fish and eggs), and tea. This information may be used to design potential dietary regimen for NPC prevention.

The HLA-DRB1 allele polymorphisms and nasopharyngeal carcinoma

Human leukocyte antigen (HLA)-DRB1 has been reported to influence individual's susceptibility to nasopharyngeal carcinoma (NPC) by many studies in recent years; however, these studies provided controversial results. The meta-analysis was thus conducted here to estimate the relationship between HLA-DRB1 polymorphisms and NPC. After an extensive review of journals from various databases (PubMed, the Web of Science, Embase, China National Knowledge Internet (CNKI), and Wanfang Database), 8 out of 69 case-control studies, including 778 cases and 1148 controls, were extracted. The results showed that 4 of 13 polymorphisms allele are statistically significantly associated with NPC, among them, HLA-DRB1*3, HLA-DRB1*9, and HLA-DRB1*10 may increase the risk of NPC while HLA-DRB1*01 has the opposite effect. The pooled odds ratio and 95 % confidence interval (CI) were 1.702 [95 % CI (1.047, 2.765)], 1.363 [95 % CI (1.029, 1.806)], 1.989 [95 % CI (1.042, 3.799)], and 0.461 [95 % CI (0.315, 0.676)], respectively. In a further ethnicity-based subgroup analysis, HLA-DRB1*08, HLA-DRB1*11, and HLA-DRB1*16 were found to be linked with NPC in Asian, Tunisian, and Caucasian, respectively. In Asian, HLA-DRB1*03, 08, and 10 may elevate the risk whereas HLA-DRB1*09 could lower it. In Tunisian, HLA-DRB1*01 and 11 are the protective factors while HLA-DRB1*03 is the only risk factor. In Caucasian, HLA-DRB1*01 and 03 increase the risk and HLA-DRB1*16 lowers it. The most frequent statistically associated gene is found to be HLA-DRB1*03 which has protective influence on Asian and Tunisian. In conclusion, HLA-DRB1*01, DRB1*03, DRB1*09, and DRB1*10 are related with NPC susceptibility, and the association of HLA-DRB1*08, DRB1*11, and DRB1*16 with NPC risk are significantly different in different ethnicities.

Dietary patterns and the risk of esophageal squamous cell carcinoma: A population-based case-control study in a rural population

BACKGROUND & AIMS

Few studies were available in exploring the roles of dietary patterns in the development of esophageal cancer, especially in China. This study aimed to investigate the roles of dietary patterns in the risk of esophageal squamous cell carcinoma (ESCC) in a Chinese rural population.

METHODS

A population-based cases-control study was designed and conducted in Yanting County, Sichuan Province of China during two years (between June 2011 and May 2013). A total of 942 pairs of ESCC cases and controls were recruited. A food frequency questionnaire was adopted to collect information of dietary consumption. Dietary patterns were extracted by using principle component and factor analysis based on 24 dietary groups. Odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated by using logistic regression model, with adjustment for possible confounding variables.

RESULTS

Four major dietary patterns were identified, which were labeled as "prudent", "vegetable and fruits", "processed food" and "alcohol drinking". In comparison of the highest with the lowest quartiles of pattern scores, the processed food pattern (OR: 2.84, 95% CI: 2.13-3.80) and alcohol drinking pattern (OR: 2.69, 95% CI: 1.95-3.71) were significantly associated with an increased risk of ESCC, while the vegetable and fruit pattern (OR: 0.70, 95% CI: 0.53-0.92) was associated with reduced risk by 30%. The prudent pattern was associated with a reduced risk by 33% (OR: 0.67, 95% CI: 0.50-0.88) in a multivariate logistic regression model, but no statistical significance was reached in a composite model.

CONCLUSIONS

The results suggest an important role of dietary patterns in ESCC. Diets rich in vegetables and fruits may decrease the risk of ESCC, whereas diets rich in processed food and drinking alcohol may increase the risk.

Integrated genomic analysis suggests MLL3 is a novel candidate susceptibility gene for familial nasopharyngeal carcinoma

BACKGROUND

Little is known about genetic factors associated with nasopharyngeal carcinoma (NPC). To gain insight into NPC etiology, we performed whole exome sequencing on germline and tumor DNA from three closely related family members with NPC.

METHODS

The family was ascertained through the Pediatric Familial Cancer Clinic at The University of Chicago (Chicago, IL). The diagnosis of NPC was confirmed pathologically for each individual. For each sample sequenced, 97.3% of the exome was covered at 5×, with an average depth of 44×. Candidate germline and somatic variants associated with NPC were identified and prioritized using a custom pipeline.

RESULTS

We discovered 72 rare deleterious germline variants in 56 genes shared by all three individuals. Of these, only three are in previously identified NPC-associated genes, all of which are located within MLL3, a gene known to be somatically altered in NPC. One variant introduces an early stop codon in MLL3, which predicts complete loss-of-function. Tumor DNA analysis revealed somatic mutations and Epstein-Barr virus (EBV) integration events; none, however, were shared among all three individuals.

CONCLUSIONS

These data suggest that inherited mutations in MLL3 may have predisposed these three individuals from a single family to develop NPC, and may cooperate with individually acquired somatic mutations or EBV integration events in NPC etiology.

IMPACT

Our finding is the first instance of a plausible candidate high penetrance inherited mutation predisposing to NPC.

Association of fruit and vegetables with the risk of nasopharyngeal cancer: evidence from a meta-analysis

Quantification of the association between the intake of vegetables and fruit and risk of nasopharyngeal cancer (NPC) is controversial. Thus, we conducted a meta-analysis to assess the relationship between vegetables and fruit and NPC risk. Pertinent studies were identified by a search in PubMed, Web of Knowledge and Wan Fang Med Online. Random-effects models were used to calculate summary relative risks (RRs) and the corresponding 95% confidence intervals (CIs). Publication bias was estimated using Egger's regression asymmetry test. Finally, 15 articles comprising 8208 NPC cases were included in this meta-analysis. The combined results showed that there was significant association between vegetables and fruit intake and NPC risk. The pooled RRs were 0.60 (95% CI = 0.47–0.76) for vegetables and 0.63 (95% CI = 0.56–0.70) for fruit. No publication bias was detected. Our analysis indicated that intake of vegetables and fruit may have a protective effect on NPC. Since the potential biases and confounders could not be ruled out completely in this meta-analysis, further studies are needed.

Metabolite profiling of edible bird's nest using gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry

RATIONALE

Edible bird's nest (EBN) is a renowned food item in the Chinese community due to the therapeutic effects claimed to be brought about by its consumption. However, very little scientific information has been revealed to support these claims. Thus, metabolite profiling was performed to identify the metabolites and to relate them to the medicinal properties of EBN. The study also aims to further extend the results to determine any possible differences when the EBNs are classified according to their coloration, countries or production sites.

METHODS

Extraction of the metabolites was performed via sonication of EBN with methanol and chloroform. Two analytical platforms, namely gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS), were utilized to detect the metabolites. This multi-analytical platform would provide a comprehensive coverage of the metabolites in EBN. GC/MS analysis was conducted in scan mode from m/z 50-650. On the other hand, LC/MS analysis was operated in both positive and negative ion mode from m/z 150-1000.

RESULTS

Metabolites were identified and their relationships with the medicinal properties of EBN were deduced. Classification with chemometrics illustrates that EBNs could be differentiated according to their coloration, countries and production sites. This differentiation was due to the environment where the EBNs are produced. Furthermore, GC/MS was demonstrated to be more suitable for classification as the processing methods of the EBNs did not cause a significant variation in the metabolites detected by GC/MS.

CONCLUSIONS

The overall findings suggest that the novel approach of metabolite profiling offers new insights to understanding EBN and provided evidence to support the medicinal properties of EBN. In addition, the success of classification of EBNs with metabolite profiling combining with chemometrics represents a paradigm shift in the quality control of this food item.

The genomic landscape of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) has extremely skewed ethnic and geographic distributions, is poorly understood at the genetic level and is in need of effective therapeutic approaches. Here we determined the mutational landscape of 128 cases with NPC using whole-exome and targeted deep sequencing, as well as SNP array analysis. These approaches revealed a distinct mutational signature and nine significantly mutated genes, many of which have not been implicated previously in NPC. Notably, integrated analysis showed enrichment of genetic lesions affecting several important cellular processes and pathways, including chromatin modification, ERBB-PI3K signaling and autophagy machinery. Further functional studies suggested the biological relevance of these lesions to the NPC malignant phenotype. In addition, we uncovered a number of new druggable candidates because of their genomic alterations. Together our study provides a molecular basis for a comprehensive understanding of, and exploring new therapies for, NPC.

Epidemiology of virus infection and human cancer

The International Agency for Research on Cancer (IARC) has comprehensively assessed the human carcinogenicity of biological agents. Seven viruses including Epstein-Barr virus (EBV), hepatitis B virus (HBV), hepatitis C virus (HCV), Kaposi's sarcoma herpes virus (KSHV), human immunodeficiency virus, type-1 (HIV-1), human T cell lymphotrophic virus, type-1 (HTLV-1), and human papillomavirus (HPV) have been classified as Group 1 human carcinogens by IARC. The conclusions are based on the findings of epidemiological and mechanistic studies. EBV, HPV, HTLV-1, and KSHV are direct carcinogens; HBV and HCV are indirect carcinogens through chronic inflammation; HIV-1 is an indirect carcinogen through immune suppression. Some viruses may cause more than one cancer, while some cancers may be caused by more than one virus. However, only a proportion of persons infected by these oncogenic viruses will develop specific cancers. A series of studies have been carried out to assess the viral, host, and environmental cofactors of EBV-associated nasopharyngeal carcinoma, HBV/HCV-associated hepatocellular carcinoma, and HPV-associated cervical carcinoma. Persistent infection and high viral load are important risk predictors of these virus-caused cancers. Risk calculators incorporating host and viral factors have also been developed for the prediction of long-term risk of hepatocellular carcinoma. These risk calculators are useful for the triage and clinical management of infected patients. Both clinical trials and national programs of immunization or antiviral therapy have demonstrated a significant reduction in the incidence of cancers caused by HBV, HCV, and HPV. Future researches on gene-gene and gene-environment interaction of oncogenic viruses and human host are in urgent need.

Hepatoprotective effects of cod liver oil against sodium nitrite toxicity in rats

CONTEXT

Exposure to high levels of nitrites for a prolonged time have adverse health effects on several organs especially the liver due to oxidative properties. Meanwhile, cod liver oil has been reported to ameliorate organ dysfunction in animal models that involve oxidative stress.

OBJECTIVE

Examine the impact of dietary cod liver oil on sodium nitrite-induced liver damage.

MATERIALS AND METHODS

Thirty-two adult male Sprague-Dawely rats were daily treated with sodium nitrite (80 mg/kg) in presence or absence of cod liver oil (5 ml/kg). Morphological changes were assessed in liver sections. Oxidative stress and antioxidant markers were measured in serum and liver homogenates. Liver samples were used for measurements of MCP-1, DNA fragmentation and mitochondrial function.

RESULTS

The hepatoprotective effect of cod liver oil was proved by significant reduction of elevated liver enzymes and normal appearance of hepatocytes. Cod liver oil significantly reduced hepatic malondialdehyde, hydrogen peroxide and superoxide anion (224.3 ± 18.9 nmol/g, 59.3 ± 5.1 and 62.5 ± 5.1 µmol/g, respectively) compared with sodium nitrite (332.5 ± 25.5 nmol/g, 83.1 ± 8.1 and 93.9 ± 6.5 µmol/g, respectively). Cod liver oil restored hepatic cytochrome c oxidase activity after 38% reduction by sodium nitrite. Furthermore, cod liver oil significantly reduced hepatic MCP-1 (79.8 pg/mg) and DNA fragmentation (13.8%) compared with sodium nitrite (168.7 pg/mg and 41.3%, respectively).

DISCUSSION AND CONCLUSION

Cod liver oil ameliorates sodium nitrite induced hepatic impairment through several mechanisms including attenuation of oxidative stress, blocking MCP-1, reactivation of mitochondrial function and reduction of DNA fragmentation.

Habitual consumption of soy products and risk of nasopharyngeal carcinoma in Chinese adults: a case-control study

BACKGROUND AND OBJECTIVES

Many studies have shown a negative association between the consumption of soy products and the risk of some cancers, but little is known about the effect of soy consumption on nasopharyngeal carcinoma. We assessed the association between the consumption of soy products on nasopharyngeal carcinoma risk in Chinese individuals.

METHODS

This case-control study included 600 (448 males and 152 females) incident cases of nasopharyngeal carcinoma, and an equal number of controls, matched according to gender, age (± 3 y) and household type to the nasopharyngeal carcinoma cases. All subjects were recruited from hospitals in Guangzhou, China. A face-to-face interview was conducted with each study individual to collect general information and habitual dietary intake using a 78-item quantitative food-frequency questionnaire. Odds ratios and their 95% confidence intervals were estimated using conditional logistic regression analyses.

RESULTS

The median intakes of soy foods (in protein) were 0.5/0.5, 1.4/1.7, 2.7/3.3 and 6.1/7.7 (male/female) g/d in the quartiles 1 to 4. Both univariate and multivariate analyses showed no significant association between the consumption of soy proteins or soy isoflavones and the risk of nasopharyngeal carcinoma. The adjusted odds ratios (95% confidence intervals) between extreme quartiles were 0.97 (0.66-1.45) for soy proteins and 0.97 (0.66-1.42) for total isoflavones. Null associations were also observed between intake of the individual isoflavones daidzein, genistein and glycitein and NPC risk, with adjusted odds ratios for the extreme quartiles ranging between 0.73 and 1.23.

CONCLUSION

Habitual consumption of soy products had no significant effect on the risk of nasopharyngeal carcinoma in Chinese adults with a relatively low intake.

Secular trends of salted fish consumption and nasopharyngeal carcinoma: a multi-jurisdiction ecological study in 8 regions from 3 continents

BACKGROUND

Despite salted fish being a classical risk factor of Nasopharyngeal Carcinoma (NPC), whether secular trends in salted fish consumption worldwide accounted for changes in NPC rates were unknown. The relationship between vegetable and cigarette consumption to NPC risk worldwide were also largely uncertain. We investigated the longitudinal trends in standardised NPC incidence/mortality rates across 8 regions and their associations with secular trends in salted fish, vegetable and tobacco consumptions.

METHODS

Age standardised mortality rate (ASMR) and age standardised incidence rate (ASIR) of NPC were obtained from the WHO cancer mortality database and Hong Kong Cancer Registry. Per capita consumption of salted fish, tobacco and vegetables in Hong Kong and 7 countries (China, Finland, Japan, Portugal, Singapore, United Kingdom and United States) were obtained from the Food and Agriculture Organization of the United Nation (FAO) and Hong Kong Trade and Census Statistics. Pearson correlation and multivariate analysis were performed to examine both crude and adjusted associations.

RESULTS

There were markedly decreasing trends of NPC ASIR and ASMR in Hong Kong over the past three decades, which were correlated with corresponding secular changes in salted fish consumption per capita (Pearson r for 10 cumulative years : ASIR = 0.729 (male), 0.674 (female); ASMR = 0.943 (male), 0.622 (female), all p < 0.05 except for female ASMR). However such associations no longer correlated with adjustments for decreasing tobacco and increasing vegetable consumption per capita (Pearson r for 10 cumulative years: ASIR = 2.007 (male), 0.339 (female), ASMR = 0.289 (male), 1.992 (female), all p > 0.05). However, there were no clear or consistent patterns in relations between NPC ASIR and ASMR with salted fish consumption across 7 regions in 3 continents.

CONCLUSIONS

Our results do not support the notion that changes in salted fish consumption had played an important role in explaining secular trends of NPC rates in Hong Kong and worldwide. Further studies should explore other lifestyle and genetic factors. However, our findings do support the potentially protective effects of vegetable consumption against NPC.