Cancer patterns in nasopharyngeal carcinoma multiplex families in Taiwan

Kinetics of EBV antibody-based NPC risk scores in Taiwan NPC multiplex families

Nasopharyngeal carcinoma (NPC) risk prediction models based on Epstein-Barr virus (EBV)-antibody testing have shown potential for screening of NPC; however, the long-term stability is unclear. Here, we investigated the kinetics of two EBV-antibody NPC risk scores within the Taiwan NPC Multiplex Family Study. Among 545 participants with multiple blood samples, we evaluated the stability of a 2-marker enzyme-linked immunosorbent assay score and 13-marker multiplex serology score using the intra-class correlation coefficient (ICC) by fitting a linear mixed model that accounted for the clustering effect of multiple measurements per subject and age. We also estimated the clustering of positive tests using Fleiss's kappa statistic. Over an average 20-year follow-up, the 2-marker score showed high stability over time, whereas the 13-marker score was more variable (p < .05). Case-control status is associated with the kinetics of the antibody response, with higher ICCs among cases. Positive tests were more likely to cluster within the same individual for the 2-marker score than the 13-marker score (p < .05). The 2-marker score had an increase in specificity from ~90% for single measurement to ~96% with repeat testing. The 13-marker score had a specificity of ~73% for a single measurement that increased to ~92% with repeat testing. Among individuals who developed NPC, none experienced score reversion. Our findings suggest that repeated testing could improve the specificity of NPC screening in high-risk NPC multiplex families. Further studies are required to determine the impact on sensitivity, establish optimal screening intervals, and generalize these findings to general population settings in high-risk regions.

Cancer patterns in nasopharyngeal carcinoma multiplex families over 15 years

BACKGROUND

Genetic and environmental factors are important determinants of nasopharyngeal carcinoma (NPC). NPC is associated with Epstein-Barr virus (EBV) infection. Studies have reported familial aggregation of NPC, but evidence has been mixed for elevated rates of cancers other than NPC.

METHODS

The authors reassessed their previous evaluation of familial aggregation of cancer in 348 high-risk Taiwanese multiplex families with 2 or more NPC cases enrolled between 1980 and 2003. Participants were linked to the Taiwan National Cancer Registry and National Death Registry to identify cancers.

RESULTS

In all, 2590 individuals contributed 37,959 person-years over an average of 15 years of follow-up; 314 incident cancers were identified. The authors computed multiple primary standardized incidence ratios (MP-SIRs) to evaluate the overall risk and the risk of infection-associated, EBV-associated, and individual cancers. The overall MP-SIR was 1.24 (95% confidence interval [CI], 1.10-1.38). The exclusion of excess NPC risk led to an overall MP-SIR of 1.11 (95% CI, 0.98-1.25). Similarly, the risk of cancers associated with infectious agents was driven by the excess in NPC, and its exclusion led to an MP-SIR of 1.22 (95% CI, 0.99-1.48) for infection-associated cancers and to an MP-SIR of 1.18 (95% CI, 0.72-1.82) for EBV-associated cancers. The authors observed a significant excess of second cancers among NPC cases (oral cancer, mouth cancer, tongue cancer, gum cancer, nasal cavity cancer, bone cancer, and non-Hodgkin lymphoma).

CONCLUSIONS

This reassessment of the largest NPC multiplex family study confirms the presence of NPC coaggregation within families in Taiwan but does not provide evidence for a broader familial syndrome involving NPC and other tumors. Among NPC cases, elevated rates of secondary cancers, mostly at the, head and neck and hematopoietic cancers suggest radiation treatment effects on subsequent cancer risk.

The Evolving Epidemiology of Nasopharyngeal Carcinoma

BACKGROUND

The epidemiology of nasopharyngeal carcinoma (NPC) has long been a source of fascination due to the malignancy's striking geographic distribution, the involvement of the oncogenic Epstein-Barr virus (EBV), the unique association with intake of Chinese-style salt-preserved fish, and etiologic heterogeneity by histologic subtype.

METHODS

This review summarizes the current epidemiologic literature on NPC, highlighting recent results from our population-based case-control study in southern China.

RESULTS

Findings from our case-control study provide new insight into the epidemiology of NPC, including a diminished role of Chinese-style salt-preserved fish, a profound impact of EBV genetic sequence variation, modest positive associations with passive smoking and household air pollution, and possible effects of oral health and the oral microbiome. Recent findings from other studies include a protective association with infectious mononucleosis, suggesting a causal role of early EBV infection; familial risk conferred by shared genetic variation in the host antibody-mediated immune response to EBV infection; and an unclear association with occupational exposure to formaldehyde.

CONCLUSIONS

To shed further light on the interplay of environmental, genetic, and viral causes of NPC, large pooled studies must accumulate sufficient cases with detailed exposure data.

IMPACT

New epidemiologic findings have reshaped the causal model for NPC.

Epstein-Barr Virus-Based Nasopharyngeal Carcinoma (NPC) Risk Prediction Scores Are Elevated in NPC Multiplex Family Members in Taiwan

Nasopharyngeal carcinoma (NPC) is caused by Epstein-Barr virus (EBV) and is more likely to occur in susceptible families. Whether genetic susceptibility operates through altered EBV control is incompletely understood. We used a NPC risk prediction model based on 14 EBV markers to compare risk score distribution in unaffected members from multiplex families with that in population-based controls. Despite the absence of NPC at the time of antibody measurement, we observed an upward shift in risk score among multiplex family members compared to the general population, consistent with the possibility that genetic factors affect NPC risk through alterations in EBV control.

Artificial Intelligence (AI)-Based Systems Biology Approaches in Multi-Omics Data Analysis of Cancer

Cancer is the manifestation of abnormalities of different physiological processes involving genes, DNAs, RNAs, proteins, and other biomolecules whose profiles are reflected in different omics data types. As these bio-entities are very much correlated, integrative analysis of different types of omics data, multi-omics data, is required to understanding the disease from the tumorigenesis to the disease progression. Artificial intelligence (AI), specifically machine learning algorithms, has the ability to make decisive interpretation of "big"-sized complex data and, hence, appears as the most effective tool for the analysis and understanding of multi-omics data for patient-specific observations. In this review, we have discussed about the recent outcomes of employing AI in multi-omics data analysis of different types of cancer. Based on the research trends and significance in patient treatment, we have primarily focused on the AI-based analysis for determining cancer subtypes, disease prognosis, and therapeutic targets. We have also discussed about AI analysis of some non-canonical types of omics data as they have the capability of playing the determiner role in cancer patient care. Additionally, we have briefly discussed about the data repositories because of their pivotal role in multi-omics data storing, processing, and analysis.

Whole-Exome Sequencing of Nasopharyngeal Carcinoma Families Reveals Novel Variants Potentially Involved in Nasopharyngeal Carcinoma

Genetic susceptibility is likely involved in nasopharyngeal carcinoma (NPC), a cancer caused by Epstein-Barr virus (EBV) infection. Understanding of genetic factors involved in NPC and how they contribute to EBV-induced carcinogenesis is limited. We conducted whole-exome capture/sequencing among 251 individuals from 97 multiplex families from Taiwan (205 affected, 21 obligate carriers, and 25 unaffected) using SeqCap EZ Human Exome Library v3.0 and Illumina HiSeq. Aligned sequences were filtered to identify likely-to-be-functional deleterious variants that co-segregated with disease. Ingenuity Pathway analysis was performed. Circulating magnesium levels were measured in 13 individuals in 2 families with NIPAL1 mutations and in 197 sporadic NPC cases and 237 controls. We identified variants in 12 genes likely involved in cancer pathogenesis, viral infection or immune responses to infection. These included genes postulated to be involved in magnesium transport (NIPAL1), EBV cell entry (ITGB6), modulation of EBV infection (BCL2L12, NEDD4L), telomere biology (CLPTM1L, BRD2, HNRNPU), modulation of cAMP signaling (RAPGEF3), DNA repair (PRKDC, MLH1), and Notch signaling (NOTCH1, DLL3). Pathway based analysis demonstrated enrichment for Notch signaling genes (p-value = 0.0006). Evaluation of individuals within NIPAL1 families suggested lower serum magnesium in NPC compared to unaffected members. A significant reduction in serum magnesium levels was observed among sporadic NPC cases compared to controls (7.1% NPC/1.7% controls below normal range; OR = 4.5; 95% CI = 1.4,14) and is consistent with findings demonstrating a role for magnesium channeling in T-cell responses to EBV. We identified novel genes associated with NPC that point to new areas of inquiry to better understand genetic factors that determine the fate of viral infections and/or otherwise predisposes to NPC.

Site-specific familial risk and survival of familial and sporadic head and neck cancer

The vast majority of head and neck cancers (HNCs) are sporadic squamous cell carcinomas, smoking and heavy drinking being the main risk factors. However, little is known about the possible role of family history and the importance of inherited factors versus shared environment. We used Swedish population-based registries to study the family history of HNC. In order to estimate the risk for family members to get the same cancer, and the risk for cancer-specific death in patients with a family history of HNC compared with patients without a family history, multivariate Cox proportional hazards analyses were performed. A 1.43-fold increased risk for developing HNC in the first-degree relatives (FDRs) of HNC patients [hazard ratio (HR), 1.43; 95% CI, 1.28-1.61] was found, when compared with relatives of healthy controls. In spouses of patients with HNC, the risk for developing any HNC was moderately increased (HR, 1.25; 95% CI, 1.01-1.53), compared with spouses of healthy controls. In addition, a 1.34-fold increased risk for death of HNC was found in HNC patients with a family history of HNC (HR, 1.34; 95% CI, (1.03-1.73) compared with HNC patients without a family history. We found an increased risk for HNC in relatives and spouses of HNC patients, when compared with family members of healthy controls. This suggests that in addition to inherited factors, shared environmental factors have a significant role in the development of the cancer. Family history of HNC was associated with worse survival in a newly diagnosed HNC patient.

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.

Familial clustering of nasopharyngeal carcinoma in non-endemic area. Report of three families

Nasopharyngeal carcinoma is the predominant tumour type arising in the nasopharynx. Its aetiology is multifactorial; racial and geographical distribution, EBV infection and environmental exposure to specific substances are considered risk factors. This condition is endemic in some Asian areas, where a genetic predisposition in its oncogenesis has been established. There is a strong susceptibility between nasopharyngeal carcinoma and HLA, where related specific haplotypes have been found. In areas where the incidence is low, there are few reported cases of families affected. We report 3 cases of families with nasopharyngeal carcinoma among siblings, in the non-Asian population, probably related to EBV infection.

Hepatitis B virus infection and risk of nasopharyngeal carcinoma in southern China

BACKGROUND

Whether or not hepatitis B virus (HBV) infection plays a role in the development of nasopharyngeal carcinoma (NPC) is largely unknown. Our study aimed to assess the association between HBV infection and the risk of NPC in Southern China.

METHODS

We conducted a case-control study including 711 NPC cases and two groups of controls. The first control group consisted of 656 individuals with other benign tumors unrelated to HBV infection and the second group consisted of 680 healthy population controls. Multivariable ORs and corresponding 95% confidence intervals (CI) for NPC were estimated by logistic regression.

RESULTS

Patients with NPC had higher prevalence of antibodies against hepatitis B core antigen-positive [anti-HBc-(+); 47.26%] compared with either benign tumor controls (39.33%; P < 0.01) or healthy controls (41.18%; P = 0.04). In multivariable models adjusting for a set of risk factors for NPC, anti-HBc-(+) was significantly associated with a higher risk of NPC [adjusted OR (AOR), 1.40; 95% CI, 1.12-1.74 compared with the benign tumor controls and AOR, 1.48; 95% CI, 1.05-2.08 compared with the healthy controls]. The association was not modified by hepatitis B surface antigen (HBsAg) status. Finally, compared with the healthy controls, individuals with both anti-HBc-(+) and EBV antibodies had largely increased risk of NPC (AOR, 141.82; 95% CI, 68.73-292.62).

CONCLUSION

Our study suggests that HBV infection is associated with NPC risk in Southern China.

IMPACT

Prevention for HBV infection may play a role in the development of NPC.

WTC-01, a novel synthetic oxime-flavone compound, destabilizes microtubules in human nasopharyngeal carcinoma cells in vitro and in vivo

BACKGROUND AND PURPOSE

Dynamic polymerization of microtubules is essential for cancer cell growth and metastasis, and microtubule-disrupting agents have become the most successful anti-cancer agents in clinical use. Besides their antioxidant properties, flavonoids also exhibit strong microtubule-disrupting activity and inhibit tumour growth. We have designed, synthesized and tested a series of oxime/amide-containing flavone derivatives. Here we report the evaluation of one compound, WTC-01 for its anti-proliferative effects in human cancer cells.

EXPERIMENTAL APPROACH

We used a range of cancer cell lines including two human nasopharyngeal carcinoma (NPC) cell lines, measuring proliferation, cell cycle and apoptosis, along with caspase levels and mitochondrial membrane potentials. Assays of tubulin polymerisation in vitro and computer modelling of the colchicine binding site in tubulin were also used. In mice, pharmacokinetics and growth of NPC-derived tumours were studied.

KEY RESULTS

WTC-01 was most potent against proliferation of NPC cells (IC50 = 0.45 μM), inducing accumulation of cells in G2 /M and increasing apoptosis, time- and concentration-dependently. The colchicine competition-binding experiments and computer modelling results suggested that WTC-01 causes microtubule disruption via binding to the colchicine-binding site of tubulin resulting in mitochondrial membrane damage and cell apoptosis via activation of caspase-9/-3 without noticeable activation of the caspase-8. Notably, our in vivo studies demonstrated that at doses of 25 and 50 mg·kg(-1) , WTC-01 exhibited good pharmacokinetic properties and completely inhibited the growth of NPC-TW01 cells in a xenograft nude mouse model.

CONCLUSIONS AND IMPLICATIONS

WTC-01, a new synthetic oxime-containing flavone, exhibited potent anti-tumour activity against NPC cells and merits further investigation.

Cancer risk in the relatives of patients with nasopharyngeal carcinoma—a register-based cohort study in Sweden

BACKGROUND

Little is known about cancer susceptibility among relatives of nasopharyngeal carcinoma (NPC) patients in non-endemic areas. We conducted a register-based cohort study to assess the relative risks (RRs) of cancer in families of NPC probands in Sweden.

METHODS

By linking 11,602,616 Swedish-born individuals (defined as 'general population') identified from national censuses to the Swedish Cancer Register and Multi-Generation Register, we identified 9157 relatives (3645 first-degree and 5512 second-degree) of 1211 NPC probands. Cancer incidence during 1961-2009 was ascertained through the Cancer Register. Relative risks of cancer in the relatives of NPC probands, compared with the rest of the general population, were calculated from Poisson regression models.

RESULTS

First-degree relatives had higher risks of NPC (N=2, RR=4.29, 95% confidence interval (CI)=1.07 to 17.17) and cancers of the larynx (N=5, RR=2.53, 95% CI=1.05 to 6.09), prostate (N=76, RR=1.35, 95% CI=1.07 to 1.68), and thyroid (N=10, RR=2.44, 95% CI=1.31 to 4.53) than the rest of the general population. In addition, a raised risk of cancer of the salivary glands was observed among first-degree relatives of probands with undifferentiated NPC (N=2, RR=6.64, 95% CI=1.66 to 26.57). In contrast, a decreased risk of colorectal cancer was observed in first- and second-degree relatives (N=43, RR=0.71, 95% CI=0.53 to 0.96).

CONCLUSION

The increased risk of NPC and certain other cancers among first-degree relatives may be explained by shared genetic and environmental risk factors, the latter including Epstein-Barr virus infection and smoking or by increased diagnostic intensity.

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.

Familial nasopharyngeal carcinomas possess distinguished clinical characteristics in southern China

OBJECTIVE

To compare clinical characteristics between familial nasopharyngeal carcinomas (NPCs) and sporadic NPCs in Guangdong province, China, a high-risk area.

METHODS

Between 1991 and 2001, 993 NPC patients treated at the Cancer Center of Sun Yat-Sen University in Guangdong were randomly selected as probands. Information about NPC among the probands' relatives and other information were obtained from a retrospective review of the patients' medical records. The patients were divided into sporadic NPC, low-frequency familial NPC (one NPC patient in addition to the proband in three generations), and high-frequency familial NPC (2 or more additional NPC patients in three generations) groups. Pathological and clinical characteristics were compared among these groups.

RESULTS

Of the 993 patients, 131 (13.2%) had a familial history of NPC. The average age at diagnosis was the lowest in the high-frequency familial NPC group (39 years; P=0.048). Although the overall survival (OS), distant metastasis-free survival (DMFS), and disease-free survival (DFS) rates did not differ between familial and sporadic NPCs, the locoregional recurrence-free survival (LRFS) rate increased in the order sporadic NPCs, low-frequency familial NPCs, and high-frequency familial NPCs (P=0.009), with 5-year rates of 70%, 83%, and 87%, respectively. Multivariate analysis showed that family history of NPC was an independent favorable prognostic factor for LRFS, with adjusted hazard ratio (aHR) of 0.548, 95% CI (0.342-0.878). The high LRFS for familial NPCs was mainly noted among young, advanced-stage patients who received continuous radiation treatment.

CONCLUSIONS

Genetic factors may play an important role in the etiology of high-frequency familial NPC and underlie the early age of onset and sensitivity to radiotherapy.

Epstein-Barr virus serology as a potential screening marker for nasopharyngeal carcinoma among high-risk individuals from multiplex families in Taiwan

BACKGROUND

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV)-associated cancer that is highly treatable when diagnosed early, with 5-year disease-free survival of approximately 90%. However, NPC is typically diagnosed at advanced stages, in which disease-free survival is <50%. There is, therefore, a need for clinical tools to assist in early NPC detection, particularly among high-risk individuals.

METHODS

We evaluated the ability of anti-EBV IgA antibodies to detect incident NPC among high-risk Taiwanese individuals. NPC cases (N = 21) and age- and sex-matched controls (N = 84) were selected. Serum collected before NPC diagnosis was tested for ELISA-based IgA antibodies against the following EBV peptides: EBNA1, VCAp18, EAp138, Ead_p47, and VCAp18 + EBNA1 peptide mixture. The sensitivity, specificity, and screening program parameters were calculated.

RESULTS

EBNA1 IgA had the best performance characteristics. At an optimized threshold value, EBNA1 IgA measured at baseline identified 80% of the high-risk individuals who developed NPC during follow-up (80% sensitivity). However, approximately 40% of high-risk individuals who did not develop NPC also tested positive (false positives). Application of EBNA1 IgA as a biomarker to detect incident NPC in a previously unscreened, high-risk population revealed that 164 individuals needed to be screened to detect 1 NPC and that 69 individuals tested positive per case detected.

CONCLUSIONS

EBNA1 IgA proved to be a sensitive biomarker for identifying incident NPC, but future work is warranted to develop more specific screening tools to decrease the number of false positives.

IMPACT

Results from this study could inform decisions about screening biomarkers and referral thresholds for future NPC early-detection program evaluations.

Prognostic impact of family history in southern Chinese patients with undifferentiated nasopharyngeal carcinoma

Background:

Family history of cancer is associated with developing nasopharyngeal carcinoma (NPC); however, the impact of it on survival among established NPC patients remains unknown.

Methods:

We retrospectively analysed 1773 southern Chinese patients. Associations between a first-degree family history of NPC and overall survival (OS), locoregional relapse-free survival (LRFS) and distant metastasis-free survival (DMFS) were estimated by Cox regression.

Results:

Among 1773 patients, 207 (11.7%) reported a first-degree family history of NPC. Compared with patients without a family history, the adjusted hazard ratios among those with it were 0.60 (95% confidence interval (CI), 0.37–0.98; P=0.040) for OS, 0.52 (95% CI, 0.24–1.12; P=0.096) for LRFS and 0.51 (95% CI, 0.27–0.97; P=0.040) for DMFS. There were trends for improving OS, LRFS and DMFS with increasing number of affected relatives (P_trend: 0.050, 0.114 and 0.044, respectively). But no significant benefits of family history in second- or third-degree relatives were observed. In subgroup analysis, we observed the effects of family history with restriction to male patients and those of advanced stage and treated with conventional radiotherapy and addition of chemotherapy.

Conclusion:

A first-degree family history of NPC is associated with improved survival of patients.

Invited commentary: Epstein-Barr virus-based screening for the early detection of nasopharyngeal carcinoma: a new frontier

Approximately 2 million new cases of cancer are caused by infections each year. For many of these cancers, we have been successful at developing methods for prevention or effective treatment/control. Epstein-Barr virus (EBV), a ubiquitous infection that establishes lifelong latency, was the first infection to be linked to the development of cancers, including nasopharyngeal carcinoma, lymphomas, and gastric cancer. EBV infection is linked to the development of approximately 200,000 new cancers each year, yet there have been no successful efforts to implement EBV-based strategies for the reduction in the burden of EBV-associated cancers. In this issue of the Journal, Liu et al. (Am J Epidemiol. 2013;177(3):242-250) report results from the enrollment phase of a large effort to demonstrate the efficacy of an EBV-based screening strategy to detect nasopharyngeal carcinoma at early stages and hopefully reduce the mortality associated with this disease. In this invited commentary, the design and initial findings from this demonstration project are reviewed, possible ways to enrich the effort are discussed, and populations that might benefit from EBV-based screening in the future are identified.

Characterization of ELISA detection of broad-spectrum anti-Epstein-Barr virus antibodies associated with nasopharyngeal carcinoma

Epstein-Barr virus (EBV) infection is associated with undifferentiated nasopharyngeal carcinomas (NPC). A distinct seroreactivity pattern to EBV is predictive of subsequent risk of sporadic and familial nasopharyngeal carcinomas. There are currently no accepted screening tools for guiding the clinical management of individuals at high-risk for nasopharyngeal carcinomas, particularly unaffected relatives from nasopharyngeal carcinoma multiplex families. Therefore, the reproducibility of a panel of largely synthetic peptide-based anti-EBV antibody ELISAs was evaluated and their ability to distinguish nasopharyngeal carcinoma cases from controls was explored. IgG and IgA antibodies against 6 different EBV antigens (10 assays, total) were tested on sera from 97 individuals representing the full spectrum of anti-EBV seroprevalence (i.e., healthy individuals with no known EBV seroreactivity, healthy individuals with known EBV seroreactivity, and nasopharyngeal carcinoma cases). Each specimen was tested in triplicate to assess within-batch and across-batch variation, and the triplicate testing was repeated on two separate days. Reproducibility was assessed by the coefficients of variation (CVs) and intraclass correlation coefficients (ICCs). All markers were detectable in 17% or more of samples. For all but one marker, the overall, within-batch, and across-batch CVs were below 15%, and the ICCs were above 70% for all but three markers. Sensitivity of these markers to detect prevalent nasopharyngeal carcinomas ranged from 22% to 100%, and among unaffected controls, most distinguished those with and without known seropositivity. In conclusion, a large number of EBV markers can be measured reliably in serum samples using peptide-based anti-EBV ELISAs.

Correlates of anti-EBV EBNA1 IgA positivity among unaffected relatives from nasopharyngeal carcinoma multiplex families

Background:

To determine whether non-viral nasopharyngeal carcinoma (NPC) risk factors might be associated with (and mediated through) Epstein–Barr virus (EBV) serological responses linked to NPC risk, we evaluated predictors of risk of anti-EBNA1 IgA seropositivity and other markers among unaffected relatives from a large NPC family study in Taiwan.

Methods:

Multivariate logistic regression conditioned on family was used to examine the associations between sociodemographic, dietary, lifestyle, and occupational variables and risk of anti-EBV EBNA1 IgA positivity, anti-VCA IgA, and anti-DNase positivity.

Results:

Among 2393 unaffected relatives from 319 multiplex families, 1180 (49.3%) were anti-EBV EBNA1 IgA seropositive. None of the associations with anti-EBNA1 IgA were statistically significant, except for being 31–50 years of age (vs <30, adjusted ORs 0.51–0.57). For one or more EBV serological markers, there were suggestive associations for older age, GuangDong firm salted fish, betel use, current alcohol use, and male gender.

Conclusion:

Overall, we found little evidence to suggest that non-viral NPC risk factors significantly alter EBV serological patterns, suggesting that non-viral NPC risk factors act through pathways independent of EBV serological responses.

Prognostic utility of anti-EBV antibody testing for defining NPC risk among individuals from high-risk NPC families

PURPOSE

Epstein-Barr virus (EBV) infection and a family history of nasopharyngeal carcinoma (NPC) are associated with NPC risk. We examined the risk associated with EBV markers and their clinical utility to identify NPC susceptibles within high-risk NPC families.

EXPERIMENTAL DESIGN

We evaluated antibody titers against viral capsid antigen (VCA) IgA, EBV nuclear antigen-1 (EBNA1) IgA, and DNase among unaffected relatives of NPC cases from 358 multiplex families in Taiwan. Incident NPC cases were identified via linkage to the National Cancer Registry. Clinical examinations of 924 individuals were also done to identify occult, asymptomatic NPC. Baseline EBV serology was used to estimate NPC risk using rate ratios with 95% CI. Associated sensitivity/specificity and receiver operating characteristic (ROC) curves were calculated.

RESULTS

A total of 2,444 unaffected individuals with 15,519 person-years (6.5 years median follow-up) yielded 14 incident NPC cases (nearly 11 times the general population rate). The absolute rate of NPC among anti-EBV EBNA1 IgA seropositives using a standard positivity cutoff versus an optimized cutoff point defined by ROC analyses was 265/100,000 person-years with a 4.7-fold increased risk of NPC (95% CI: 1.4-16) and 166/100,000 person-years with a 6.6-fold increase (95% CI: 1.5-61), respectively. Sensitivity and specificity using the optimized positivity cutoff points were 85.7% and 51.2%, respectively. It is estimated that active evaluation of 49% of individuals from high-risk NPC families seropositive for this marker could lead to earlier detection of up to 86% of NPC cases. Risks associated with the other three EBV markers were weaker.

CONCLUSIONS

Future efforts are needed to identify susceptibility markers among high-risk NPC families that maximize both sensitivity and specificity.