Epstein-Barr virus activates F-box protein FBXO2 to limit viral infectivity by targeting glycoprotein B for degradation.

Epstein-Barr virus (EBV) is a human cancer-related virus closely associated with lymphoid and epithelial malignancies, and EBV glycoprotein B (gB) plays an essential role in viral entry into both B cells and epithelial cells by promoting cell-cell fusion. EBV gB is exclusively modified with high-mannose-linked N-glycans and primarily localizes to the endoplasmic reticulum (ER) with low levels on the plasma membrane (PM). However, the mechanism through which gB is regulated within host cells is largely unknown. Here, we report the identification of F-box only protein 2 (FBXO2), an SCF ubiquitin ligase substrate adaptor that preferentially binds high-mannose glycans and attenuates EBV infectivity by targeting N-glycosylated gB for degradation. gB possesses seven N-glycosylation sites, and FBXO2 directly binds to these high-mannose moieties through its sugar-binding domain. The interaction promotes the degradation of glycosylated gB via the ubiquitin-proteasome pathway. Depletion of FBXO2 not only stabilizes gB but also promotes its transport from the ER to the PM, resulting in enhanced membrane fusion and viral entry. FBXO2 is expressed in epithelial cells but not B cells, and EBV infection up-regulates FBXO2 levels. In summary, our findings highlight the significance of high-mannose modification of gB and reveal a novel host defense mechanism involving glycoprotein homeostasis regulation.

Association Between Environmental Factors and Oral Epstein-Barr Virus DNA Loads: A Multicenter Cross-sectional Study in China.

Background: Oral Epstein-Barr virus (EBV) status reflects host EBV activity and potentially links to EBV-associated diseases, however, factors influencing oral EBV loads or reactivation, such as environmental exposures or host factors, are not fully understood. Methods: A 2-stage, multicenter, cross-sectional study of 6558 subjects from 21 administrative cities of southern China and 3 populations from representative geographical areas in China (referred to as the south, north, and northeastern populations) was performed. The relationships between demographical factors and environmental exposures to EBV loads were analyzed by logistic regression models. Results: Current smoking, with a dose-response effect, was found to be strongly associated with higher oral EBV loads in the pooled data, with an odds ratio of 1.58 (95% confidence interval, 1.39-1.79), as well as in each of the separate populations. The odds ratio increased to 3.06 when current smokers in southern China were compared to never smokers in northern China. Additionally, higher oral EBV loads tended to be detected in older participants, male participants, and participants in southern China. Conclusions: This study provided evidence linking the effect of host-environmental factors, particularly smoking, to oral EBV activity. It could strengthen our understanding of the possible causal roles of EBV-related diseases, which may help to prevent or mitigate EBV-associated diseases.

An extended genome-wide association study identifies novel susceptibility loci for nasopharyngeal carcinoma.

To further identify novel susceptibility loci of nasopharyngeal carcinoma (NPC), we here extended our previous genome-wide association study (GWAS) by boosting statistical power with larger sample size and validating more SNPs in the ranking list based on the GWAS P-values. The discovery stage consisting of 463,250 SNPs in 1,583 cases and 2,979 controls of southern Chinese ancestry revealed 1,257 top SNPs to be associated with NPC, which were brought forward for validation in 1,925 cases and 1,947 controls of southern Chinese. Further, 11 SNPs were selected for another independent validation in 3,538 cases and 3,644 controls of southern Chinese. The joint analysis with 7,046 cases and 8,570 controls resulted in two associations surpassing genome-wide significance (P < 5 × 10-8), including TERT-CLPTM1L at chromosome 5p15 (rs401681; P = 2.65 × 10-14; odds ratio, OR = 0.82) and CIITA at chromosome 16p13 (rs6498114; P = 4.01 × 10-9; OR = 0.87). Conditional analysis revealed that rs401681 accounts for all the tested associations at TERT-CLPTM1L locus, which has been linked with multiple cancers' susceptibilities. Moreover, bioinformatics analyses showed that both SNPs are located in the regulatory regions and correlated with the expression of nearby genes (rs401681 for CLPTM1L and TERT, and rs6498114 for CIITA). CLPTM1L and TERT have been implicated in cancers, and CIITA is considered as the "master control factor" for the expression of NPC-associated MHC class II genes. These suggested that both SNPs might be functional. Altogether, our findings expand our understanding of the genetic contribution to NPC risk and provide novel biological insights into NPC pathogenesis.

Genetic risk of extranodal natural killer T-cell lymphoma: a genome-wide association study.

BACKGROUND: Extranodal natural killer T-cell lymphoma (NKTCL), nasal type, is a rare and aggressive malignancy that occurs predominantly in Asian and Latin American populations. Although Epstein-Barr virus infection is a known risk factor, other risk factors and the pathogenesis of NKTCL are not well understood. We aimed to identify common genetic variants affecting individual risk of NKTCL. METHODS: We did a genome-wide association study of 189 patients with extranodal NKTCL, nasal type (WHO classification criteria; cases) and 957 controls from Guangdong province, southern China. We validated our findings in four independent case-control series, including 75 cases from Guangdong province and 296 controls from Hong Kong, 65 cases and 983 controls from Guangdong province, 125 cases and 1110 controls from Beijing (northern China), and 60 cases and 2476 controls from Singapore. We used imputation and conditional logistic regression analyses to fine-map the associations. We also did a meta-analysis of the replication series and of the entire dataset. FINDINGS: Associations exceeding the genome-wide significance threshold (p<5 × 10(-8)) were seen at 51 single-nucleotide polymorphisms (SNPs) mapping to the class II MHC region on chromosome 6, with rs9277378 (located in HLA-DPB1) having the strongest association with NKTCL susceptibility (p=4·21 × 10(-19), odds ratio [OR] 1·84 [95% CI 1·61-2·11] in meta-analysis of entire dataset). Imputation-based fine-mapping across the class II MHC region suggests that four aminoacid residues (Gly84-Gly85-Pro86-Met87) in near-complete linkage disequilibrium at the edge of the peptide-binding groove of HLA-DPB1 could account for most of the association between the rs9277378*A risk allele and NKTCL susceptibility (OR 2·38, p value for haplotype 2·32 × 10(-14)). This association is distinct from MHC associations with Epstein-Barr virus infection. INTERPRETATION: To our knowledge, this is the first time that a genetic variant conferring an NKTCL risk is noted at genome-wide significance. This finding underlines the importance of HLA-DP antigen presentation in the pathogenesis of NKTCL. FUNDING: Top-Notch Young Talents Program of China, Special Support Program of Guangdong, Specialized Research Fund for the Doctoral Program of Higher Education (20110171120099), Program for New Century Excellent Talents in University (NCET-11-0529), National Medical Research Council of Singapore (TCR12DEC005), Tanoto Foundation Professorship in Medical Oncology, New Century Foundation Limited, Ling Foundation, Singapore National Cancer Centre Research Fund, and the US National Institutes of Health (1R01AR062886, 5U01GM092691-04, and 1R01AR063759-01A1).

Association between XRCC3 Thr241Met polymorphism and nasopharyngeal carcinoma risk: evidence from a large-scale case-control study and a meta-analysis.

The X-ray repair cross-complementing group 3 (XRCC3) Thr241Met polymorphism (rs861539, C > T) has drawn wide attentions as its association with cancer risk and its involvement in DNA repair. Several studies have attempted to link rs861539 to nasopharyngeal cancer (NPC) risk; however, the sample sizes of these studies are small and the results are controversial. To investigate the relationship of rs861539 and NPC susceptibility, we conducted a large-scale case-control study involving 4001 NPC cases and 2967 controls of southern Chinese. Logistic regression analysis revealed significant association for rs861539 and NPC risk under the recessive model (TT vs. CT + CC) with adjustment of age and gender (odds ratio, OR = 2.72; 95 % CI 1.10-6.72; P = 0.03). Further, meta-analysis involving 4457 NPC cases and 4132 controls from four studies showed consistent association of TT carriers and NPC risk (OR = 3.12; 95 % CI 1.58-6.13; P = 0.001). Taken together, our findings based on large-scale sample size suggested rs861539 at XRCC3 to be associated with NPC risk through recessive model.

A single nucleotide polymorphism in the Epstein-Barr virus genome is strongly associated with a high risk of nasopharyngeal carcinoma.

BACKGROUND: Epstein-Barr virus (EBV) commonly infects the general population and has been associated with nasopharyngeal carcinoma (NPC), which has a high incidence in certain regions. This study aimed to address how EBV variations contribute to the risk of NPC. METHODS: Using logistic regression analysis and based on the sequence variations at EBV-encoded RPMS1, a multi-stage association study was conducted to identify EBV variations associated with NPC risk. A protein degradation assay was performed to characterize the functional relevance of the RPMS1 variations. RESULTS: Based on EBV-encoded RPMS1 variations, a single nucleotide polymorphism (SNP) in the EBV genome (locus 155391: G>A, named G155391A) was associated with NPC in 157 cases and 319 healthy controls from an NPC endemic region in South China [P < 0.001, odds ratio (OR) = 4.47, 95% confidence interval (CI) 2.71-7.37]. The results were further validated in three independent cohorts from the NPC endemic region (P < 0.001, OR = 5.20, 95% CI 3.18-8.50 in 168 cases vs. 241 controls, and P < 0.001, OR = 5.27, 95% CI 4.06-6.85 in 726 cases vs. 880 controls) and a non-endemic region (P < 0.001, OR = 7.52, 95% CI 3.69-15.32 in 58 cases vs. 612 controls). The combined analysis in 1109 cases and 2052 controls revealed that the SNP G155391A was strongly associated with NPC (P(combined) < 0.001, OR = 5.27, 95% CI 4.31-6.44). Moreover, the frequency of the SNP G155391A was associated with NPC incidence but was not associated with the incidences of other EBV-related malignancies. Furthermore, the protein degradation assay showed that this SNP decreased the degradation of the oncogenic RPMS1 protein. CONCLUSIONS: Our study identified an EBV variation specifically and significantly associated with a high risk of NPC. These findings provide insights into the pathogenesis of NPC and strategies for prevention.

Genome-wide scan for familial nasopharyngeal carcinoma reveals evidence of linkage to chromosome 4.

Nasopharyngeal carcinoma (NPC) occurs with high frequency in Asian populations, especially among people of Cantonese ancestry. In areas with high incidence, NPC clusters in families, which suggests that both geography and genetics may influence disease risk. Although the HLA-Bw46 locus is associated with increased risk of NPC, no predisposing genes have been identified so far. Here we report the results of a genome-wide search carried out in families at high risk of NPC from Guangdong Province, China. Parametric analyses provide evidence of linkage to the D4S405 marker on chromosome 4 with a logarithm of odds for linkage (lod) score of 3.06 and a heterogeneity-adjusted lod (hlod) score of 3.21. Fine mapping with additional markers flanking D4S405 resulted in a lod score of 3.54 and hlod score of 3.67 for the region 4p15.1-q12. Multipoint nonparametric linkage analysis gives lod scores of 3.54 at D4S405 (P = 5.4 x 10(-5)) and 4.2 at D4S3002 (P = 1.1 x 10(-5)), which is positioned 4.5 cM away from D4S405. When Epstein Barr virus antibody titer was included as a covariate, the lod scores reached 4.70 (P = 2.0 x 10(-5)) and 5.36 (P = 4.36 x 10(-6)) for D4S405 and D4S3002, respectively. Our findings provide evidence of a major susceptibility locus for NPC on chromosome 4 in a subset of families.

The propensity for tumorigenesis in human induced pluripotent stem cells is related with genomic instability.

The discovery of induced pluripotent stem cells(iPSCs) is a promising advancement in the field of regenerative medicine. Previous studies have indicated that the teratoma-forming propensity of iPSCs is variable; however, the relationship between tumorigenic potential and genomic instability in human iPSCs (HiPSCs) remains to be fully elucidated. Here, we evaluated the malignant potential of HiPSCs by using both colony formation assays and tumorigenicity tests. We demonstrated that HiPSCs formed tumorigenic colonies when grown in cancer cell culture medium and produced malignancies in immunodeficient mice. Furthermore, we analyzed genomic instability in HiPSCs using whole-genome copy number variation analysis and determined that the extent of genomic instability was related with both the cells' propensity to form colonies and their potential for tumorigenesis. These findings indicate a risk for potential malignancy of HiPSCs derived from genomic instability and suggest that quality control tests, including comprehensive tumorigenicity assays and genomic integrity validation, should be rigorously executed before the clinical application of HiPSCs. In addition, HiPSCs should be generated through the use of combined factors or other approaches that decrease the likelihood of genomic instability.

Non-overlapping epitopes on the gHgL-gp42 complex for the rational design of a triple-antibody cocktail against EBV infection.

Epstein-Barr virus (EBV) is closely associated with cancer, multiple sclerosis, and post-acute coronavirus disease 2019 (COVID-19) sequelae. There are currently no approved therapeutics or vaccines against EBV. It is noteworthy that combining multiple EBV glycoproteins can elicit potent neutralizing antibodies (nAbs) against viral infection, suggesting possible synergistic effects. Here, we characterize three nAbs (anti-gp42 5E3, anti-gHgL 6H2, and anti-gHgL 10E4) targeting different glycoproteins of the gHgL-gp42 complex. Two antibody cocktails synergistically neutralize infection in B cells (5E3+6H2+10E4) and epithelial cells (6H2+10E4) in vitro. Moreover, 5E3 alone and the 5E3+6H2+10E4 cocktail confer potent in vivo protection against lethal EBV challenge in humanized mice. The cryo-EM structure of a heptatomic gHgL-gp42 immune complex reveals non-overlapping epitopes of 5E3, 6H2, and 10E4 on the gHgL-gp42 complex. Structural and functional analyses highlight different neutralization mechanisms for each of the three nAbs. In summary, our results provide insight for the rational design of therapeutics or vaccines against EBV infection.

Direct sequencing and characterization of a clinical isolate of Epstein-Barr virus from nasopharyngeal carcinoma tissue by using next-generation sequencing technology.

Epstein-Barr virus (EBV)-encoded molecules have been detected in the tumor tissues of several cancers, including nasopharyngeal carcinoma (NPC), suggesting that EBV plays an important role in tumorigenesis. However, the nature of EBV with respect to genome width in vivo and whether EBV undergoes clonal expansion in the tumor tissues are still poorly understood. In this study, next-generation sequencing (NGS) was used to sequence DNA extracted directly from the tumor tissue of a patient with NPC. Apart from the human sequences, a clinically isolated EBV genome 164.7 kb in size was successfully assembled and named GD2 (GenBank accession number HQ020558). Sequence and phylogenetic analyses showed that GD2 was closely related to GD1, a previously assembled variant derived from a patient with NPC. GD2 contains the most prevalent EBV variants reported in Cantonese patients with NPC, suggesting that it might be the prevalent strain in this population. Furthermore, GD2 could be grouped into a single subtype according to common classification criteria and contains only 6 heterozygous point mutations, suggesting the monoclonal expansion of GD2 in NPC. This study represents the first genome-wide analysis of a clinical isolate of EBV directly extracted from NPC tissue. Our study reveals that NGS allows the characterization of genome-wide variations of EBV in clinical tumors and provides evidence of monoclonal expansion of EBV in vivo. The pipeline could also be applied to the study of other pathogen-related malignancies. With additional NGS studies of NPC, it might be possible to uncover the potential causative EBV variant involved in NPC.

Expression of heat shock protein 70 in nasopharyngeal carcinomas: different expression patterns correlate with distinct clinical prognosis.

BACKGROUND: Heat shock protein 70, a stress protein, has been implicated in tumor progression. However, its role in nasopharyngeal carcinoma (NPC) progression has not yet been clearly investigated. METHODS: Immunohistochemistry (IHC) was employed to examine the expression patterns of Hsp70, human leukocyte antigen -A (HLA-A) in NPC tissue samples. RESULTS: The expression of Hsp70 exhibited different spatial patterns among nuclear, membrane and cytoplasm in 507 NPC tumor tissues. Kaplan-Meier survival analysis demonstrated that different Hsp70 expression patterns are correlated with different patient outcomes. High membranal and cytoplasmic levels of Hsp70 predicted good survival of patients. In contrast, high nuclear abundance of Hsp70 correlated with poor survival. Moreover, the membranal and cytoplasmic levels of Hsp70 were positively correlated with levels of the MHC I molecule HLA-A. CONCLUSIONS: Different Hsp70 expression patterns had distinct predictive values. The different spatial abundance of Hsp70 may imply its important role in NPC development and provide insight for the development of novel therapeutic strategies involving immunotherapy for NPC.

CRL2KLHDC3 mediates p14ARF N-terminal ubiquitylation degradation to promote non-small cell lung carcinoma progression.

Kelch superfamily involves a variety of proteins containing multiple kelch motif and is well characterized as substrate adaptors for CUL3 E3 ligases, which play critical roles in carcinogenesis. However, the role of kelch proteins in lung cancer remains largely unknown. In this study, the non-small cell lung cancer (NSCLC) patients with higher expression of a kelch protein, kelch domain containing 3 (KLHDC3), showed worse overall survival. KLHDC3 deficiency affected NSCLC cell lines proliferation in vitro and in vivo. Further study indicated that KLHDC3 mediated CUL2 E3 ligase and tumor suppressor p14ARF interaction, facilitating the N-terminal ubiquitylation and subsequent degradation of p14ARF. Interestingly, Gefitinib-resistant NSCLC cell lines displayed higher KLHDC3 protein levels. Gefitinib and Osimertinib medications were capable of upregulating KLHDC3 expression to promote p14ARF degradation in the NSCLC cell lines. KLHDC3 shortage significantly increased the sensitivity of lung cancer cells to epidermal growth factor receptor (EGFR)-targeted drugs, providing an alternative explanation for the development of Gefitinib and Osimertinib resistance in NSCLC therapy. Our works suggest that CRL2KLHDC3 could be a valuable target to regulate the abundance of p14ARF and postpone the occurrence of EGFR-targeted drugs resistance.

Human genetic variants of homologous recombination repair genes first found to be associated with Epstein-Barr virus antibody titers in healthy Cantonese.

Epstein-Barr virus (EBV) infection is a major risk factor for nasopharyngeal carcinoma (NPC). Despite high prevalence of infection among the general population worldwide, only a small proportion of infected individuals presents with seropositivity for EBV-specific IgA antibodies. This seropositive subgroup of EBV carriers has an elevated cumulative risk for NPC during their lifetime. Previous studies reported that the host homologous recombination repair (HRR) system participates in EBV lytic replication, suggesting a potential mechanism to influence EBV reactivation status and thus seropositivity. To investigate whether genetic variants of HRR genes are associated with the serostatus in a healthy population, we investigated the association between seropositivity for anti-VCA-IgA and 156 tagging SNPs in 35 genes connected with HRR in an observational study among 755 healthy Cantonese speakers in southern China. Six variant alleles of MDC1, RAD54L, TP53BP1, RPA1, LIG3 and RFC1 exhibited associations with seropositivity (p(trend) from 0.0085 to 0.00027). Our study provides evidence that genetic variation within the HRR might affect an individual's propensity for EBV seropositive status of anti-VCA IgA antibody.

Elevated Epstein-Barr virus seroreactivity among unaffected members of families with nasopharyngeal carcinoma.

Serum antibodies to Epstein-Barr virus (EBV) antigens can be used to predict the risk of nasopharyngeal carcinoma (NPC). To investigate whether EBV seropositivity rates were higher among healthy family members from multiplex and sporadic families with NPC (i.e., families with multiple or single cases) compared to the general population, a study was conducted on 2,665 unaffected individuals from 140 multiplex and 413 sporadic families. The titers of the IgA antibody to the EBV capsid antigen (VCA-IgA) were compared to those of 904 controls from the general population. The VCA-IgA titer was correlated among sibling pairs to a high significance in both family types (P < 0.0001 and P = 0.0005 for the multiplex and the sporadic families, respectively); parent-offspring pairs also showed significant correlation (P < 0.0001 and P = 0.0002, respectively); and spouse pairs were correlated, but at lower significance levels (P = 0.0790 and P = 0.0040, respectively). When compared to the controls, among first-degree relatives in the multiplex families, the age- and gender-adjusted odds ratio (OR) was 2.06 (95% confidence interval 1.56-2.71), 3.55 (2.24-5.64), and 2.25 (1.57-3.23) for siblings, parents, and children, respectively. In the sporadic families, the adjusted OR was 1.55 (1.21-2.00) and 2.08 (1.51-2.86) for siblings and parents, respectively. The adjusted P-value of spouses lost significance in the multiplex families, but remained significant in the sporadic families (P = 0.0146). In conclusion, EBV seropositivity rates were elevated among unaffected family members in both multiplex and sporadic families with NPC.

A comprehensive risk score for effective risk stratification and screening of nasopharyngeal carcinoma.

Using Epstein-Barr virus (EBV)-based markers to screen populations at high risk for nasopharyngeal carcinoma (NPC) is an attractive preventive approach. Here, we develop a comprehensive risk score (CRS) that combines risk effects of EBV and human genetics for NPC risk stratification and validate this CRS within an independent, population-based dataset. Comparing the top decile with the bottom quintile of CRSs, the odds ratio of developing NPC is 21 (95% confidence interval: 12-37) in the validation dataset. When combining the top quintile of CRS with EBV serology tests currently used for NPC screening in southern China, the positive prediction value of screening increases from 4.70% (serology test alone) to 43.24% (CRS plus serology test). By identifying individuals at a monogenic level of NPC risk, this CRS approach provides opportunities for personalized risk prediction and population screening in endemic areas for the early diagnosis and secondary prevention of NPC.

Sequencing of DC-SIGN promoter indicates an association between promoter variation and risk of nasopharyngeal carcinoma in cantonese.

BACKGROUND: The dendritic cell-specific intercellular adhesion molecule 3 grabbing non-integrin (DC-SIGN) is an important pathogen recognition receptor of the innate immune system. DC-SIGN promoter variants play important role in the susceptibility to various infectious diseases. Nasopharyngeal carcinoma (NPC) is a malignancy that is common in southern China and whether DC-SIGN promoter variants have effects on susceptibility to NPC is still unknown. The aim of this study is to ascertain the potential involvement of DC-SIGN promoter single nucleotide polymorphisms (SNPs) in NPC susceptibility. METHODS: We conducted a case control study based on Cantonese population including 444 NPC patients and 464 controls matched on age and sex. The 1041 bp of DC-SIGN promoter region was directly sequenced for all samples. Sequence alignment and SNP search were inspected using DNAStar analysis programs and haplotype frequencies were estimated in Haploview V 4.0. The associations between the SNPs and the risk of NPC were analyzed using chi-square test and non-conditional logistic regression analysis with SPSS 13.0 software. RESULTS: A total of six variants were observed in the DC-SIGN promoter region and DC-SIGN -139 GG and -939 AA were significantly associated with NPC risk with adjusted Odds Ratios (ORs) of 2.10 (95% confidence interval [CI] = 1.23-3.59; P = 0.006) and 2.52 (1.29-4.93; P = 0.007) respectively and subjects carrying the risk allele DC-SIGN -871 G had 1.47-fold (95% CI = 1.14-1.90) increased risks of developing NPC (P = 0.003). Haplotype analysis revealed that h1 'AAAG' was significantly associated with protection against NPC (OR = 0.69; P = 0.0002) and the association was still significant when using 1000 permutation test runs (P = 0.001). CONCLUSIONS: Our study indicated that DC-SIGN promoter variants appear to be involved in the susceptibility to NPC and the detailed mechanism of this effect need further studies.

Traditional Cantonese diet and nasopharyngeal carcinoma risk: a large-scale case-control study in Guangdong, China.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is rare in most parts of the world but is a common malignancy in southern China, especially in Guangdong. Dietary habit is regarded as an important modifier of NPC risk in several endemic areas and may partially explain the geographic distribution of NPC incidence. In China, rapid economic development during the past few decades has changed the predominant lifestyle and dietary habits of the Chinese considerably, requiring a reassessment of diet and its potential influence on NPC risk in this NPC-endemic area. METHODS: To evaluate the association between dietary factors and NPC risk in Guangdong, China, a large-scale, hospital-based case-control study was conducted. 1387 eligible cases and 1459 frequency matched controls were recruited. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were estimated using a logistic regression model, adjusting for age, sex, education, dialect, and habitation household type. RESULTS: Observations made include the following: 1) consumption of canton-style salted fish, preserved vegetables and preserved/cured meat were significantly associated with increased risk of NPC, with enhanced odds ratios (OR) of 2.45 (95% CI: 2.03-2.94), 3.17(95% CI: 2.68-3.77) and 2.09 (95% CI: 1.22-3.60) respectively in the highest intake frequency stratum during childhood; 2) consumption of fresh fruit was associated with reduced risk with a dose-dependent relationship (p = 0.001); and 3) consumption of Canton-style herbal tea and herbal slow-cooked soup was associated with decreased risk, with ORs of 0.84 (95% CI: 0.68-1.03) and 0.58 (95% CI: 0.47-0.72) respectively in the highest intake frequency stratum. In multivariate analyses, these associations remained significant. CONCLUSIONS: It can be inferred that previously established dietary risk factors in the Cantonese population are still stable and have contributed to the incidence of NPC.

Germline Polymorphisms and Length of Survival of Nasopharyngeal Carcinoma: An Exome-Wide Association Study in Multiple Cohorts.

Germline polymorphisms are linked with differential survival outcomes in cancers but are not well studied in nasopharyngeal carcinoma (NPC). Here, a two-phase association study is conducted to discover germline polymorphisms that are associated with the prognosis of NPC. The discovery phase includes two consecutive hospital cohorts of patients with NPC from Southern China. Exome-wide genotypes at 246 173 single nucleotide polymorphisms (SNPs) are determined, followed by survival analysis for each SNP under Cox proportional hazard regression model. Candidate SNP is replicated in another two independent cohorts from Southern China and Singapore. Meta-analysis of all samples (n = 5553) confirms that the presence of rs1131636-T, located in the 3'-UTR of RPA1, confers an inferior overall survival (HR = 1.33, 95% CI = 1.20-1.47, P = 6.31 × 10-8). Bioinformatics and biological assays show that rs1131636 has regulatory effects on upstream RPA1. Functional studies further demonstrate that RPA1 promotes the growth, invasion, migration, and radioresistance of NPC cells. Additionally, miR-1253 is identified as a suppressor for RPA1 expression, likely through regulation of its binding affinity to rs1131636 locus. Collectively, these findings provide a promising biomarker aiding in stratifying patients with poor survival, as well as a potential drug target for NPC.

A case-control and a family-based association study revealing an association between CYP2E1 polymorphisms and nasopharyngeal carcinoma risk in Cantonese.

Nasopharyngeal carcinoma (NPC) is rare in most parts of the world but is more prevalent in Southern China, especially in Guangdong. The cytochrome P450 2E1 (CYP2E1) has been recognized as one of the critically important enzymes involved in oxidizing carcinogens and is probably to be associated with NPC carcinogenesis. To systematically investigate the association between genetic variants in CYP2E1 and NPC risk in Cantonese, two independent studies, a family-based association study and a case-control study, were conducted using the haplotype-tagging single-nucleotide polymorphism approach. A total of 2499 individuals from 546 nuclear families were initially genotyped for the family-based association study. Single-nucleotide polymorphisms (SNPs) rs9418990, rs915908, rs8192780, rs1536826, rs3827688 and one haplotype h2 (CGTGTTAA) were revealed to be significantly associated with the NPC phenotype (P = 0.045-0.003 and P = 0.003, respectively). To follow up the initial study, a case-control study including 755 cases and 755 controls was conducted. Similar results were observed in the case-control study in individuals <46 years of age and had a history of cigarette smoking, with odds ratios (ORs) of specific genotypes ranging from 1.88 to 2.99 corresponding to SNP rs9418990, rs3813865, rs915906, rs2249695, rs8192780, rs1536826, rs3827688 and of haplotypes h2 with OR = 1.65 (P = 0.026), h5 (CCCGTTAA) with OR = 2.58 (P = 0.007). The values of false-positive report probability were <0.015 for six SNPs, suggesting that the reported associations are less probably to be false. This study provides robust evidence for associations between genetic variants of CYP2E1 and NPC risk.

Clinical values of multiple Epstein-Barr virus (EBV) serological biomarkers detected by xMAP technology.

BACKGROUND: Serological examination of Epstein-Barr virus (EBV) antibodies has been performed for screening nasopharyngeal carcinoma (NPC) and other EBV-associated diseases. METHODS: By using xMAP technology, we examined immunoglobulin (Ig) A antibodies against Epstein-Barr virus (EBV) VCA-gp125, p18 and IgA/IgG against EA-D, EBNA1 and gp78 in populations with distinct diseases, or with different genetic or geographic background. Sera from Cantonese NPC patients (n = 547) and healthy controls (n = 542), 90 members of high-risk NPC families and 52 non-endemic healthy individuals were tested. Thirty-five of NPC patients were recruited to observe the kinetics of EBV antibody levels during and after treatment. Patients with other EBV-associated diseases were collected, including 16 with infectious mononucleosis, 28 with nasal NK/T cell lymphoma and 14 with Hodgkin's disease. RESULTS: Both the sensitivity and specificity of each marker for NPC diagnosis ranged 61-84%, but if combined, they could reach to 84.5% and 92.4%, respectively. Almost half of NPC patients displayed decreased EBV immunoactivities shortly after therapy and tumor recurrence was accompanied with high EBV antibody reactivates. Neither the unaffected members from high-risk NPC families nor non-endemic healthy population showed statistically different EBV antibody levels compared with endemic controls. Moreover, elevated levels of specific antibodies were observed in other EBV-associated diseases, but all were lower than those in NPC. CONCLUSION: Combined EBV serological biomarkers could improve the diagnostic values for NPC. Diverse EBV serological spectrums presented in populations with different EBV-associated diseases, but NPC patients have the highest EBV activity.