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Background:Epstein–Barr virus (EBV) is linked to multiple cancers, including classical Hodgkin lymphoma (cHL), endemic Burkitt lymphoma (eBL), nasopharyngeal carcinoma (NPC), and extranodal natural killer/T-cell lymphoma (NKTCL).Methods:Anti-EBV IgG and IgA antibody responses targeting 202 sequences from 86 EBV proteins were measured using the same EBV whole proteome array across four case–control studies investigating EBV-positive cHL, eBL, NPC, and NKTCL (407 cases/620 controls). We grouped EBV-targeted antibodies into pathways by immunoglobulin type (IgA and IgG) and life-cycle stage (latent, immediate early lytic, early lytic, late lytic, and glycoprotein) and evaluated their association with each cancer type. In an additional analysis, we focused on the subset of 46 individual antibodies representing the top candidates for each cancer and compared their associations across the four cancer types using multivariable linear regression models.Results:IgA antibody responses targeting all EBV life-cycle stages were associated with NPC but limited to anti-early lytic stage for cHL. NPC and eBL were associated with IgG antibodies across the viral life cycle; cHL with antibodies in the early lytic, late lytic and glycoprotein stages; and NKTCL with antibodies in the latent, immediate early lytic and early lytic phases. EBNA3A, BBLF1, BDLF4, and BLRF2 IgG antibodies were associated with all cancer types.Conclusions:Our observed similarities and differences across four EBV-associated cancers may inform EBV-related oncogenesis.Impact:Understanding the comparative humoral immune response across EBV-related cancers may aid in identifying shared etiologic roles of EBV proteins and inform unique pathogenic processes for each cancer.

Supplementary Table S2 shows summary of participant characteristics

Supplementary Methods S1 expands upon data and statistical methods.

Background: Epstein–Barr virus (EBV) is linked to multiple cancers, including classical Hodgkin lymphoma (cHL), endemic Burkitt lymphoma (eBL), nasopharyngeal carcinoma (NPC), and extranodal natural killer/T-cell lymphoma (NKTCL). Methods: Anti-EBV IgG and IgA antibody responses targeting 202 sequences from 86 EBV proteins were measured using the same EBV whole proteome array across four case–control studies investigating EBV-positive cHL, eBL, NPC, and NKTCL (407 cases/620 controls). We grouped EBV-targeted antibodies into pathways by immunoglobulin type (IgA and IgG) and life-cycle stage (latent, immediate early lytic, early lytic, late lytic, and glycoprotein) and evaluated their association with each cancer type. In an additional analysis, we focused on the subset of 46 individual antibodies representing the top candidates for each cancer and compared their associations across the four cancer types using multivariable linear regression models. Results: IgA antibody responses targeting all EBV life-cycle stages were associated with NPC but limited to anti-early lytic stage for cHL. NPC and eBL were associated with IgG antibodies across the viral life cycle; cHL with antibodies in the early lytic, late lytic and glycoprotein stages; and NKTCL with antibodies in the latent, immediate early lytic and early lytic phases. EBNA3A, BBLF1, BDLF4, and BLRF2 IgG antibodies were associated with all cancer types. Conclusions: Our observed similarities and differences across four EBV-associated cancers may inform EBV-related oncogenesis. Impact: Understanding the comparative humoral immune response across EBV-related cancers may aid in identifying shared etiologic roles of EBV proteins and inform unique pathogenic processes for each cancer.

Coefficient of variation by study and antibody.

Background. Epstein–Barr virus (EBV) is necessary for the development of nasopharyngeal carcinoma (NPC). By adulthood, approximately 90% of individuals test EBV-positive, but only a fraction develop cancer. Factors that identify which individuals are most likely to develop disease, including differential antibody response to the virus, could facilitate detection at early stages when treatment is most effective.Methods. We measured anti-EBV IgG and IgA antibody responses in 607 Taiwanese individuals. Antibodies were measured using a custom protein microarray targeting 199 sequences from 86 EBV proteins. Variation in response patterns between NPC cases and controls was used to develop an antibody-based risk score for predicting NPC. The overall accuracy [area under the curve (AUC)] of this risk score, and its performance relative to currently used biomarkers, was evaluated in two independent Taiwanese cohorts.Findings. Levels of 60 IgA and 73 IgG anti-EBV antibodies differed between stage I/IIa NPC cases and controls (P < 0.0002). Risk prediction analyses identified antibody targets that best discriminated NPC status—BXLF1, LF2,BZLF1, BRLF1, EAd, BGLF2, BPLF1, BFRF1, and BORF1. When combined with currently used VCA/EBNA1 IgA biomarkers, the resulting risk score predicted NPC with 93% accuracy (95% CI, 87%–98%) in the general Taiwanese population, a significant improvement beyond current biomarkers alone (82%; 95% CI, 75%–90%, P ≤ 0.01). This EBV-based risk score also improved NPC prediction in genetically high-risk families (89%; 95% CI, 82%–96%) compared with current biomarkers (78%; 95% CI, 66%–90%, P ≤ 0.03).Interpretation. We identified NPC-related differences in 133 anti-EBV antibodies and developed a risk score using this microarray dataset that targeted immune responses against EBV proteins from all stages of the viral life cycle, significantly improving the ability to predict NPC. Clin Cancer Res; 24(6); 1305–14. ©2017 AACR.

Supplemental Methods

Protein and sequence

Supplemental Tables S2-S4: Antibody Responses against 199 EBV peptide sequences and risk of early-stage NPC in a cross-sectional study

Background The role of smoking in nasopharyngeal carcinoma (NPC) remains uncertain, especially in endemic regions. We conducted an individual participant data (IPD) meta-analysis of prospective cohort studies to investigate the associations between smoking exposure and risk of NPC. Methods We obtained individual participant data of 334 935 male participants from six eligible population-based cohorts in NPC-endemic regions, including two each in Guangzhou and Taiwan, and one each in Hong Kong and Singapore. We used one- and two-stage approaches IPD meta-analysis and Cox proportional hazard models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of NPC for smoking exposure adjusting for age and drinking status. Results During 2 961 315 person-years of follow-up, 399 NPC evens were ascertained. Risks of NPC were higher in ever versus never smokers (HRone-stage = 1.32, 95% CI = 1.07-1.63, P = 0.0088; HRtwo-stage = 1.27, 1.01-1.60, 0.04). These positive associations appeared to be stronger in ever smokers who consumed 16+ cigarettes/day (HRone-stage = 1.67, 95% CI = 1.29-2.16, P = 0.0001), and in those who started smoking at age younger than 16 (2.16, 1.33-3.50, 0.0103), with dose-response relationships (P-values for trend = 0.0028 and 0.0103, respectively). Quitting (versus daily smoking) showed a small reduced risk (stopped for 5+ years: HRone-stage = 0.91, 95% CI = 0.60-1.39, P = 0.66; for former smokers: HRtwo-stage = 0.84, 0.61-1.14, 0.26). Conclusions This first IPD meta-analysis from six prospective cohorts in endemic regions has provided robust observational evidence that smoking increased NPC risk in men. NPC should be added to the 12–16 cancer sites known to be tobacco-related cancers. Strong tobacco control policies, preventing young individuals from smoking, would reduce NPC risk in endemic regions.

Background: Genetic susceptibility is associated with nasopharyngeal carcinoma (NPC). We previously identified rare variants potentially involved in familial NPC and common variants significantly associated with sporadic NPC. Methods: We conducted targeted gene sequencing of 20 genes [16 identified from the study of multiplex families, three identified from a pooled analysis of NPC genome-wide association study (GWAS), and one identified from both studies] among 819 NPC cases and 938 controls from two case–control studies in Taiwan (independent from previous studies). A targeted, multiplex PCR primer panel was designed using the custom Ion AmpliSeq Designer v4.2 targeting the regions of the selected genes. Gene-based and single-variant tests were conducted. Results: We found that NPC was associated with combined common and rare variants in CDKN2A/2B (P = 1.3 × 10−4), BRD2 (P = 1.6 × 10−3), TNFRSF19 (P = 4.0 × 10−3), and CLPTM1L/TERT (P = 5.4 × 10−3). Such associations were likely driven by common variants within these genes, based on gene-based analyses evaluating common variants and rare variants separately (e.g., for common variants of CDKN2A/2B, P = 4.6 × 10−4; for rare variants, P = 0.04). We also observed a suggestive association with rare variants in HNRNPU (P = 3.8 × 10−3) for NPC risk. In addition, we validated four previously reported NPC risk–associated SNPs. Conclusions: Our findings confirm previously reported associated variants and suggest that some common variants in genes previously linked to familial NPC are associated with the development of sporadic NPC. Impact: NPC-associated genes, including CLPTM1L/TERT, BRD2, and HNRNPU, suggest a role for telomere length maintenance in NPC etiology.

BACKGROUND: Epstein-Barr virus (EBV) is necessary for the development of nasopharyngeal carcinoma (NPC). By adulthood, ~90% of individuals test EBV-positive, but only a fraction develop cancer. Factors that identify which individuals are most likely to develop disease, including differential antibody response to the virus, could facilitate detection at early stages when treatment is most effective. METHODS: We measured anti-EBV IgG and IgA antibody responses in 607 Taiwanese individuals. Antibodies were measured using a custom protein microarray targeting 199 sequences from 86 EBV proteins. Variation in response patterns between NPC cases and controls was used to develop an antibody-based risk score for predicting NPC. The overall accuracy (area under the curve[AUC]) of this risk score, and its performance relative to currently-used biomarkers, was evaluted in two independent Taiwanese cohorts. FINDINGS: Levels of 60 IgA and 73 IgG anti-EBV antibodies differed between Stage I/IIa NPC cases and controls (P

BACKGROUND: We previously reported that higher levels of antibody targeting Epstein-Barr virus (EBV) glycoprotein350 (gp350), an EBV vaccine candidate, were protective against nasopharyngeal carcinoma (NPC) in genetically high-risk families from Taiwan. The current study attempted to extend this association to a general population cohort. METHODS: We compared total and IgA-specific gp350 antibody levels in 35 incident NPC cases and 81 disease-free controls from the Cancer Screening Program in Taiwan (23943 individuals recruited 1991–1992). Luciferase immunoprecipitation assays quantified gp350 antibody. RESULTS: Total EBVgp350 antibody levels were not higher in individuals who remained disease free compared to those who developed NPC (P = .11). This lack of a protective gp350 association persisted for cases diagnosed ≥5 years (odds ratio [OR] = 1.05; P = .91) and

Background: Little is known about variation in antibody responses targeting the full spectrum of Epstein-Barr virus (EBV)proteins and how such patterns inform disease risk. Methods: We used a microarray to measure immunoglobulin G (IgG) and immunoglobulin A (IgA) antibody responses against 199 EBV protein sequences from 5 EBV strains recovered from 289 healthy adults from Taiwan. We described positivity patterns, estimated the correlation between antibodies, and investigated the associations between environmental and genetic risk factors and variations in antibody responses. Results: Healthy adults were more likely to mount IgG antibody responses to EBV proteins (median positivity frequency, 46.5% for IgG and 17.3% for IgA; P = 1.6 × 10–46, by the Wilcoxon rank sum test). Responses against glycoproteins were particularly prevalent. The correlations between antibody responses of the same class were higher than correlations across classes. The mucosal exposure to proteins involved in EBV reactivation (as determined by the IgA response) was associated with smoking (P = .002, by the sequence kernel association test–combined), and approximately one quarter of adults displayed antibody responses associated with EBV-related cancer risk. Conclusions: These data comprehensively define the variability in human IgG and IgA antibody responses to the EBV proteome. Patterns observed can serve as the foundation for elucidating which individuals are at highest risk of EBV-associated clinical conditions and for identifying targets for effective immunodiagnostic tests.

Objectives To determine the required hepatitis B vaccine doses for subjects who were seronegative for three hepatitis B seromarkers during their youth who wish to have seroprotective antibodies against the hepatitis B surface antigen (anti-HBs). Methods We conducted a retrospective cohort study. From 2012 to 2015, graduate school students born after 1986 who were seronegative for three hepatitis B virus seromarkers at college entrance (n = 1037) were recruited. Four groups of subjects received zero to three doses of a hepatitis B vaccine booster at their free willingness, and their anti-HBs titre were measured at their graduate school entrance. Very low and extremely low antibody titres against the hepatitis B surface antigen were elucidated by graphic inference to determine the required booster dose cut-off value for seropositivity after revaccination. Results The anti-HBs seropositive rates in the four groups of subjects receiving the hepatitis B booster vaccine(s) were 17.7%, 52.1%, 78.6% and 90.9% for those receiving zero, one, two and three doses, respectively. In subjects with very low antibody titres against the hepatitis B surface antigen after one dose of the vaccine booster and subjects with an extremely low titre after two doses of the booster, the seropositive rates reached 95% at the cut-off value of 3 mIU/ml. Conclusion A seropositive rate of at least 95% can be reached by the administration of two hepatitis B booster doses to youths with extremely low antibody titres against the hepatitis B surface antigen (

Background. Epstein–Barr virus (EBV) is necessary for the development of nasopharyngeal carcinoma (NPC). By adulthood, approximately 90% of individuals test EBV-positive, but only a fraction develop cancer. Factors that identify which individuals are most likely to develop disease, including differential antibody response to the virus, could facilitate detection at early stages when treatment is most effective. Methods. We measured anti-EBV IgG and IgA antibody responses in 607 Taiwanese individuals. Antibodies were measured using a custom protein microarray targeting 199 sequences from 86 EBV proteins. Variation in response patterns between NPC cases and controls was used to develop an antibody-based risk score for predicting NPC. The overall accuracy [area under the curve (AUC)] of this risk score, and its performance relative to currently used biomarkers, was evaluated in two independent Taiwanese cohorts. Findings. Levels of 60 IgA and 73 IgG anti-EBV antibodies differed between stage I/IIa NPC cases and controls (P < 0.0002). Risk prediction analyses identified antibody targets that best discriminated NPC status—BXLF1, LF2,BZLF1, BRLF1, EAd, BGLF2, BPLF1, BFRF1, and BORF1. When combined with currently used VCA/EBNA1 IgA biomarkers, the resulting risk score predicted NPC with 93% accuracy (95% CI, 87%–98%) in the general Taiwanese population, a significant improvement beyond current biomarkers alone (82%; 95% CI, 75%–90%, P ≤ 0.01). This EBV-based risk score also improved NPC prediction in genetically high-risk families (89%; 95% CI, 82%–96%) compared with current biomarkers (78%; 95% CI, 66%–90%, P ≤ 0.03). Interpretation. We identified NPC-related differences in 133 anti-EBV antibodies and developed a risk score using this microarray dataset that targeted immune responses against EBV proteins from all stages of the viral life cycle, significantly improving the ability to predict NPC. Clin Cancer Res; 24(6); 1305–14. ©2017 AACR.

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 (ORadj = 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 national hepatitis B vaccination program in Taiwan is considered one of the most successful and effective public health programs to control chronic hepatitis B infection in the past 20 years. This review illustrates how to implement a successful hepatitis B vaccination program based on Taiwan's experience. Several important controlled randomized clinical trials on hepatitis B immunoglobulin and vaccine in Taiwan demonstrated an 80-90% protective effect among infants of mothers who were positive for either hepatitis B envelope antigen or hepatitis B surface antigen. A series of prevalence surveys on children born before and after the national vaccination program began disclosed a steady decrease in seroprevalence of hepatitis B surface antigen in Taiwan, with 78-87% effectiveness after the national vaccination program was launched. Studies on the secular trend of liver disease risk also documented a 68% decline in mortality from fulminant hepatitis in infants and a 75% decrease in the incidence of hepatocellular carcinoma in children 6-9 years of age after the national vaccination program began. In conclusion, since 1984, the national hepatitis B vaccination program has been successful in preventing acute and chronic liver diseases in Taiwan.

BACKGROUND:The association between human leukocyte antigen (HLA) genes (located in the Major Histocompatibility Complex [MHC] region of chromosome 6p21) and NPC has been known for some time. Recently, two genome-wide association studies (GWAS) conducted in Taiwan and China confirmed that the strongest evidence for NPC association was mapped to the MHC region. It is still unclear, however, whether these findings reflect direct associations with Human Leukocyte Antigen (HLA) genes and/or to other genes in this gene-rich region. METHODS:To better understand genetic associations for NPC within the MHC region of chromosome 6, we conducted an evaluation that pooled two previously conducted NPC case-control studies in Taiwan (N = 591 cases and N = 521 controls). PCR-based genotyping was performed for 12 significant SNPs identified within 6p21 in the Taiwan NPC GWAS and for the HLA-A gene (exons 2 and 3). FINDINGS:After confirming homogeneity between the two studies, pooled odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression. We found that HLA-A (p-trend = 0.0006) and rs29232 (within the GABBR1 gene; p-trend = 0.005) were independent risk factors for NPC after adjustment for age, gender, study and each other. NPC risk was highest among individuals who were homozygous for the HLA-A*0207 risk allele and carriers of the rs29232 risk allele (A). CONCLUSION:Our study suggests that most of the SNPs significantly associated with NPC from GWAS reflect previously identified HLA-A associations. An independent effect of rs29232 (GABBR1), however, remained, suggesting that additional genes within this region might be associated with NPC risk.

Background A case-control study was conducted to evaluate the role of adult diet on nasopharyngeal carcinoma (NPC) in Taiwan. Methods A total of 375 incident NPC cases and 327 controls matched to the cases on sex, age, and residence were recruited between July 1991 and December 1994. A structured questionnaire inquiring complete dietary history, socio-demographic characteristics, and other potential confounding factors was used in the personal interview. Unconditional logistic regression analysis was used to estimate multivariate-adjusted odds ratio (ORadj) with 95% confidence interval (CI) after accounting for known risk factors. Results Fresh fish (ORadj, 0.56; 95% CI, 0.38–0.83 for the highest vs. lowest tertile of intake), green tea (ORadj, 0.61; 95% CI, 0.40–0.91 for drinking ≥1 times/week vs. never) and coffee (ORadj, 0.56; 95% CI, 0.37–0.85 for drinking ≥0.5 times/week vs. never) were inversely associated with the NPC risk. No association with NPC risk was observed for the intake of meats, salted fish, fresh vegetables, fruits and milk. Intake of vitamin A from plant sources was associated with a decreased NPC risk (ORadj, 0.62; 95% CI, 0.41–0.94 for the highest vs. lowest tertile). Conclusion The study findings suggest that certain adult dietary patterns might protect against the development of NPC.

The long-term protection of hepatitis B (HB) vaccination has been debated for years. The purpose here was to evaluate the kinetic changes of antibody to HB surface antigen (anti-HBs) and define immune memory of the HB vaccine among college students who had previously received full neonatal immunization against HB. In all, 127 college students aged 18-23 years born after July 1984 who had completed HB vaccination and were seronegative for all three HB viral markers, including HB surface antigen (HBsAg), antibody to HB core protein (anti-HBc), and anti-HBs, were recruited. They received three doses of HB vaccine at enrollment, 1 month and 6 months after enrollment. Their anti-HBs titers were assayed at enrollment, 7-10 days, 1 month, 6 months, and 7 months following the first dose of HB vaccine. The anti-HBs seroprotective rates for subjects 7-10 days, 1 month, 6 months, and 7 months postvaccination were 20.5%, 75.6%, 94.5%, and 99.2%, respectively. Those who were seroprotective at 7 to 10 days after one dose of HB vaccine booster developed significantly higher levels of anti-HBs at 1 and 6 months than those not developing seroprotective anti-HBs response at an earlier timepoint. Conclusion: At least one-quarter of HB vaccinees have lost their immune memory to the HB vaccine when entering college. Immune memory to HB vaccine was identified by early seroconversion, which was present in only 20% of vaccinees in the present study. To ensure higher than 90% anti-HBs seroconversion rates, at least 2 doses of HB booster vaccines are recommended for at-risk youths who received complete HB vaccinations in neonatal or infant periods but are seronegative for HBsAg, anti-HBs, and anti-HBc in adolescence. (Hepatology 2010;)

Few long-term studies of hepatitis B virus (HBV) infection and hepatocellular carcinoma have focused on women. We used a nationwide cohort of reproductive-aged Taiwanese women to study relationships of HBV infection and parity with hepatocellular carcinoma risk.Prenatal test results were available for hepatitis B surface antigen (HBsAg) and e antigen (HBeAg) in the National Hepatitis B Vaccination Registry from 1 782 401 pregnant women tested from October 1, 1983, through March 31, 2000. Data from the 306 women who were diagnosed with hepatocellular carcinoma were ascertained during 15 901 722 person-years of follow-up through linkage with National Cancer Registry and National Death Certification Registry. We used Cox proportional hazards models to investigate the association of age and reproductive and serological parameters with the risk of hepatocellular carcinoma.Incidence rates for hepatocellular carcinoma were 0.55, 7.91, and 8.76 per 100 000 person-years among women who were HBsAg negative (ie, noncarriers), HBsAg positive plus HBeAg negative, and HBsAg positive plus HBeAg positive, respectively (compared with noncarriers, for HBsAg-positive and HBeAg-positive women, age-adjusted hazard ratio [HR] for developing hepatocellular carcinoma = 17.31, 95% confidence interval [CI] = 12.08 to 24.81; and for HBsAg-negative plus HBeAg-positive women, HR = 13.94, 95% CI = 10.34 to 18.79). Incidence rates were 0.39, 3.10, and 9.01 per 100 000 person-years, respectively, among persistent noncarriers, HBsAg-serocleared carriers, and persistent HBsAg carriers (compared with noncarriers, for HBsAg-serocleared carriers, age-adjusted HR = 7.95, 95% CI = 3.50 to 18.04; and for HBsAg persistence, HR = 23.13, 95% CI = 14.23 to 37.61). Incidence rates were 2.04, 1.55, and 1.66 per 100 000 person-years for women who had one, two, or three or more children, respectively (compared with one child, for two children, age- and HBsAg-adjusted HR = 0.68, 95% CI = 0.50 to 0.93; and for three or more children, HR = 0.63, 95% CI = 0.42 to 0.92).The risk for hepatocellular carcinoma was statistically significantly higher among women with chronic or active HBV infections and among those with persistent HBV infection or who underwent HBsAg seroclearance during follow-up than among HBV-unexposed women. This risk decreased as parity increased, independent of HBsAg status and age.

This study aimed to assess independent effects of EBV and cigarette smoking on nasopharyngeal carcinoma, which have never been assessed in long-term follow-up studies. A cohort of 9,622 men was enrolled from 1984 to 1986. Blood samples collected at study entry were tested for antibodies against EBV antigens (anti-EBV) viral capsid antigen immunoglobulin A and DNase. The cigarette smoking habit was inquired through questionnaire interview. Newly developed nasopharyngeal carcinoma cases were ascertained through computerized linkage with national cancer registry profile. Cox's proportional hazard regression analysis was used to estimate multivariate-adjusted hazard ratio with its 95% confidence interval (95% CI). During the follow-up of 173,706 person-years, 32 pathologically confirmed nasopharyngeal carcinoma cases were identified >1 year after recruitment. Increasing serum levels of anti–EBV viral capsid antigen immunoglobulin A and DNase were significantly associated with nasopharyngeal carcinoma risk in a dose-response relationship. The multivariate-adjusted hazard ratio (95% CI) of developing nasopharyngeal carcinoma for low and high antibody levels compared with seronegatives was 9.5 (2.2-40.1) and 21.4 (2.8-161.7), respectively, for anti–EBV viral capsid antigen immunoglobulin A (P < 0.001 for trend), and 1.6 (0.5-4.6) and 16.0 (5.4-47.1), respectively, for anti–EBV DNase (P < 0.001 for trend). The shorter the time interval between study entry and nasopharyngeal carcinoma diagnosis, the higher was the proportion of anti–EBV viral capsid antigen immunoglobulin A among nasopharyngeal carcinoma patients. The multivariate-adjusted hazard ratio (95% CI) was 3.0 (1.3-7.2) for ≥30 pack-years of cumulative cigarette smoking compared with