Jian Liao

Evaluation and Integration of Genetic Signature for Prediction Risk of Nasopharyngeal Carcinoma in Southern China

Genetic factors, as well as environmental factors, play a role in development of nasopharyngeal carcinoma (NPC). A number of single nucleotide polymorphisms (SNPs) have been reported to be associated with NPC. To confirm these genetic associations with NPC, two independent case-control studies from Southern China comprising 1166 NPC cases and 2340 controls were conducted. Seven SNPs in ITGA9 at 3p21.3 and 9 SNPs within the 6p21.3 HLA region were genotyped. To explore the potential clinical application of these genetic markers in NPC, we further evaluate the predictive/diagnostic role of significant SNPs by calculating the area under the curve (AUC). Results. The reported associations between ITGA9 variants and NPC were not replicated. Multiple loci of GABBR1, HLA-F, HLA-A, and HCG9 were statistically significant in both cohorts (P combined range from 5.96 × 10−17 to 0.02). We show for the first time that these factors influence NPC development independent of environmental risk factors. This study also indicated that the SNP alone cannot serve as a predictive/diagnostic marker for NPC. Integrating the most significant SNP with IgA antibodies status to EBV, which is presently used as screening/diagnostic marker for NPC in Chinese populations, did not improve the AUC estimate for diagnosis of NPC.

Trends in incidence and mortality of nasopharyngeal carcinoma over a 20–25 year period (1978/1983–2002) in Sihui and Cangwu counties in southern China

BackgroundNasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world but is common in southern China. A recent report from the Hong Kong Cancer Registry, a high-risk area for NPC in southern China, showed that incidence rate decreased by 29% for males and by 30% for females from 1980–1999, while mortality rate decreased by 43% for males and 50% for females. Changing environmental risk factors and improvements in diagnosis and treatment were speculated to be the major factors contributing to the downward trend of the incidence and mortality rates of NPC. To investigate the secular trends in different Cantonese populations with different socio-economic backgrounds and lifestyles, we report the incidences and mortality rates from two population-based cancer registries in Sihui and Cangwu counties from 1978–2002.MethodsIncidence and mortality rates were aggregated by 5-year age groups and 5 calendar years. To adjust for the effect of difference in age composition for different periods, the total and age-specific rates of NPC incidence and mortality rate were adjusted by direct standardization according to the World Standard Population (1960). The Estimated Annual Percentage Change (EAPC) was used as an estimate of the trend.ResultsThe incidence rate of NPC has remained stable during the recent two decades in Sihui and in females in Cangwu, with a slight increase observed in males in Cangwu from 17.81 to 19.76 per 100,000. The incidence rate in Sihui is 1.4–2.0 times higher during the corresponding years than in Cangwu, even though the residents of both areas are of Cantonese ethnicity. A progressive decline in mortality rate was observed in females only in Sihui, with an average reduction of 6.3% (p = 0.016) per five-year period.ConclusionTo summarize, there is great potential to work in the area of NPC prevention and treatment in southern China to decrease NPC risk and improve survival risk rates in order to reduce M:I ratios. Future efforts on effective prevention, early detection and treatment strategies were also discussed in this paper. Furthermore, the data quality and completeness also need to be improved.

Evaluation of nonviral risk factors for nasopharyngeal carcinoma in a high-risk population of Southern China.

To understand the role of environmental and genetic influences on nasopharyngeal carcinoma (NPC) in populations at high risk of NPC, we have performed a case‐control study in Guangxi Province of Southern China in 2004–2005. NPC cases (n = 1,049) were compared with 785 NPC‐free matched controls who were seropositive for IgA antibodies (IgA) to Epstein‐Barr virus (EBV) capsid antigen (VCA)—a predictive marker for NPC in Chinese populations. A questionnaire was used to capture exposure and NPC family history data. Risk factors associated with NPC in a multivariant analysis model were the following: (i) a first, second or third degree relative with NPC [attributable risk (AR)= 6%, odds ratio (OR) = 3.1, 95% confidence interval (CI) = 2.0–4.9, p < 0.001]; (ii) consumption of salted fish 3 or more than 3 times per month (AR = 3%, OR = 1.9, 95% CI = 1.1–3.5, p = 0.035); (iii) exposure to domestic wood cooking fires for more than 10 years (AR = 69%, OR = 5.8, 95% CI = 2.5–13.6, p < 0.001); and (iv) exposure to occupational solvents for 10 or less years (AR = 4%, OR = 2.6, 95% CI = 1.4–4.8, p = 0.002). Consumption of preserved meats or a history of tobacco smoking were not associated with NPC (p > 0.05). We also assessed the contribution of EBV/IgA/VCA antibody serostatus to NPC risk—32.2% of NPC can be explained by IgA+ status. However, family history and environmental risk factors cumulatively explained only 2.7% of NPC development in NPC high risk population. These findings should have important public health implications for NPC risk reduction in endemic regions.

The Principal Genetic Determinants for Nasopharyngeal Carcinoma in China Involve the HLA Class I Antigen Recognition Groove

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy facilitated by Epstein-Barr Virus infection. Here we resolve the major genetic influences for NPC incidence using a genome-wide association study (GWAS), independent cohort replication, and high-resolution molecular HLA class I gene typing including 4,055 study participants from the Guangxi Zhuang Autonomous Region and Guangdong province of southern China. We detect and replicate strong association signals involving SNPs, HLA alleles, and amino acid (aa) variants across the major histocompatibility complex-HLA-A, HLA –B, and HLA -C class I genes (PHLA-A-aa-site-62u200a=u200a7.4×10−29; P HLA-B-aa-site-116u200a=u200a6.5×10−19; P HLA-C-aa-site-156u200a=u200a6.8×10−8 respectively). Over 250 NPC-HLA associated variants within HLA were analyzed in concert to resolve separate and largely independent HLA-A, -B, and -C gene influences. Multivariate logistical regression analysis collapsed significant associations in adjacent genes spanning 500 kb (OR2H1, GABBR1, HLA-F, and HCG9) as proxies for peptide binding motifs carried by HLA- A*11:01. A similar analysis resolved an independent association signal driven by HLA-B*13:01, B*38:02, and B*55:02 alleles together. NPC resistance alleles carrying the strongly associated amino acid variants implicate specific class I peptide recognition motifs in HLA-A and -B peptide binding groove as conferring strong genetic influence on the development of NPC in China.

Haplotype-dependent HLA susceptibility to nasopharyngeal carcinoma in a Southern Chinese population

We have conducted a comprehensive case–control study of a nasopharyngeal carcinoma (NPC) population cohort from Guangxi Province of Southern China, a region with one of the highest NPC incidences on record. A total of 1407 individuals including NPC patients, healthy controls, and their adult children were examined for the human leukocyte antigen (HLA) association, which is so far the largest NPC cohort reported for such studies. Stratified analysis performed in this study clearly demonstrated that while NPC protection is associated with independent HLA alleles, most NPC susceptibility is strictly associated with HLA haplotypes. Our study also detected for the first time that A*0206, a unique A2 subtype to South and Southeast Asia is also associated with a high risk for NPC. HLA-A*0206, HLA-B*3802 alleles plus the A*0207–B*4601 and A*3303–B*5801 haplotypes conferred high risk for NPC showing a combined odds ratio (OR) of 2.6 (P<0.0001). HLA alleles that associate with low risk for NPC include HLA-A*1101, B*27, and B*55 with a combined OR of 0.42 (P<0.0001). The overall high frequency of NPC-susceptible HLA factors in the Guangxi population is likely to have contributed to the high-NPC incidence in this region.

Genetic Polymorphisms of CYP2E1 , GSTP1 , NQO1 and MPO and the Risk of Nasopharyngeal Carcinoma in a Han Chinese Population of Southern China

BackgroundSouthern China is a major area for endemic nasopharyngeal carcinoma (NPC). Genetic factors as well as environmental factors play a role in development of NPC. To investigate the roles of previously described carcinogen metabolism gene variants for NPC susceptibility in a Han Chinese population, we conducted a case-control study in two independent study population groups afflicted with NPC in Guangdong and Guangxi Provinces of southern China.MethodsFive single nucleotide polymorphisms (SNPs) of CYP2E1-rs2031920, CYP2E1-rs6413432, GSTP1-rs947894, MPO-rs2333227 and NQO1-rs1800566 were genotyped by PCR-based RFLP, sequencing and TaqMan assay in 358 NPC cases and 629 controls (phase I cohort). Logistic regression analysis was used to estimate odds ratios (OR) and 95% confidence intervals (CI). To confirm our results, sixteen tag SNPs for GSTP1, MPO, NQO1 (which 100% covered these genes), and 4 functional SNPs of CYP2E1 were genotyped in another cohort of 213 NPC cases and 230 controls (phase II cohort).ResultsNo significant associations in NPC risk were observed for the five polymorphisms tested in the phase I cohort. In an additional stratified analysis for phase I, there was no significant association between cases and controls in NPC high risk population (EBV/IgA/VCA positive population). Analysis of 14 tagging SNPs within the same genes in an independent phase II cohort were in agreement with no SNPs significantly associated with NPC.ConclusionsOur results suggest that polymorphism of CYP2E1, GSTP1, MPO and NQO1 genes does not contribute to overall NPC risk in a Han Chinese in southern China.

Genetic factors leading to chronic Epstein-Barr virus infection and nasopharyngeal carcinoma in South East China: Study design, methods and feasibility

Nasopharyngeal carcinoma (NPC) is a complex disease caused by a combination of Epstein-Barr virus chronic infection, the environment and host genes in a multi-step process of carcinogenesis. The identity of genetic factors involved in the development of chronic Epstein-Barr virus infection and NPC remains elusive, however. Here, we describe a two-phase, population-based, case-control study of Han Chinese from Guangxi province, where the NPC incidence rate rises to a high of 25-50 per 100,000 individuals. Phase I, powered to detect single gene associations, enrolled 984 subjects to determine feasibility, to develop infrastructure and logistics and to determine error rates in sample handling. A microsatellite screen of Phase I study participants, genotyped for 319 alleles from 34 microsatellites spanning an 18-megabase region of chromosome 4 (4p15.1-q12), previously implicated by a linkage analysis of familial NPC, found 14 alleles marginally associated with developing NPC or chronic immunoglobulin A production (p = 0.001-0.03). These associations lost significance after applying a correction for multiple tests. Although the present results await confirmation, the Phase II study population has tripled patient enrolment and has included environmental covariates, offering the potential to validate this and other genomic regions that influence the onset of NPC.

Nasopharyngeal Epstein-Barr Virus Load: An Efficient Supplementary Method for Population-Based Nasopharyngeal Carcinoma Screening.

Serological detection of Epstein-Barr virus (EBV) antibodies is frequently used in nasopharyngeal carcinoma (NPC) mass screening. However, the large number of seropositive subjects who require close follow-up is still a big burden. The present study aimed to detect the nasopharyngeal EBV load in a high-risk population seropositive for antibodies against EBV, as well as to examine whether assay for nasopharyngeal EBV DNA load might reduce the number of high-risk subjects for follow-up and improve early detection of NPC. A prospective and population-based cohort study was conducted in southern China from 2006 through 2013. Among 22,186 participants, 1045 subjects with serum immunoglobulin A (IgA) antibodies against viral capsid antigen (VCA) titers ≥ 1:5 were defined as high-risk group, and were then followed-up for NPC occurrence. Qualified nasopharyngeal swab specimens were available from 905 participants and used for quantitative PCR assay. Our study revealed that 89% (802/905) subjects showed positive EBV DNA in nasopharyngeal swab. The nasopharyngeal EBV load in females was higher than that in males. The nasopharyngeal EBV load increased with increasing serum VCA/IgA titers. Eight cases of newly diagnosed NPC showed an extremely elevated EBV load, and 87.5% (7 of 8 patients) were early-stage NPCs. The EBV loads of 8 NPCs were significantly higher than those of 897 NPC-free subjects (mean, 2.8×106 copies/swab [range 4.8×104-1.1×108] vs. 5.6×103 [range 0-3.8×106]). Using mean EBV load in NPC-free population plus two standard deviations as cut-off value, a higher diagnostic performance was obtained for EBV load test than serum VCA/IgA test (area under ROC, 0.980 vs 0.895). In conclusion, in a prospective and population-based study we demonstrated that an additional assay of EBV load in the nasopharynx among high-risk individuals may reduce the number of subjects needed to be closely followed up and could serve as part of a NPC screening program in high-risk populations.

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

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.

Oral hygiene and risk of nasopharyngeal carcinoma - a population-based case-control study in China

Background: The association between oral health and risk of nasopharyngeal carcinoma (NPC) is largely unknown. Further understanding could shed light on potential pathogenic mechanisms and preventive measures. Methods: We conducted a population-based case–control study in southern China between 2010 and 2014. We enrolled 2,528 incident NPC cases, aged 20–74 years, and 2,596 controls, randomly selected from the total population registers, with frequency matching to the 5-year age and sex distribution of the cases by geographic region. We interviewed subjects using a structured questionnaire inquiring about oral health indicators and potential confounding factors. We used unconditional logistic regression to estimate multivariate-adjusted ORs with 95% confidence intervals (CI). Results: A higher number of filled teeth was associated with an elevated risk of NPC. Individuals with 1 to 3 and more than 3 teeth filled versus none had adjusted ORs of 1.25 (95% CI, 1.06–1.49) and 1.55 (95% CI, 1.13–2.12), respectively (Ptrend = 0.002). Conversely, the adjusted OR for those who brushed teeth twice or more per day versus once or less per day was 0.62 (95% CI, 0.55–0.70). We detected a borderline significant positive association with earlier age at first adult tooth loss. Conclusion: Our study suggested a positive association between some indicators of poor oral health and risk of NPC. Further studies are needed to confirm whether the findings are causal and, if so, to further explain the underlying mechanisms. Impact: Improvement of oral hygiene might contribute to reducing NPC risk. Cancer Epidemiol Biomarkers Prev; 25(8); 1201–7. ©2016 AACR.