Nasopharyngeal carcinoma in Chinese---salted fish or inhaled smoke?

The association between chronic sinonasal inflammation and nasopharyngeal carcinoma - A systematic review and meta-analysis

PURPOSE

There has been mounting evidence that inflammation is a key risk factor towards the development of certain cancers. Past studies have shown associations between nasopharyngeal carcinoma (NPC) and sinonasal tract inflammation. We aim to conduct a review and meta-analysis on the association between NPC and chronic sinus inflammation.

MATERIALS AND METHODS

We conducted a meta-analysis, searching 4 international databases from 1 January 1973 to 28 March 2022 for studies reporting on sinonasal inflammation and NPC in adult patients (>18 years old). We included cohort, case-control or cross-sectional studies. These studies must examine the association between a prior history of sinonasal inflammation and the risk of developing NPC. The outcome is the incidence of NPC in patients who had prior sinonasal inflammation.

RESULTS

8 studies (8245 NPC; 1,036,087 non-NPC) were included. The overall odds ratio (OR) of patients having NPC after reporting sinonasal inflammation was 1.81 (95 % CI 1.73-1.89). Of note, chronic rhinosinusitis (CRS) (OR of 1.78 (95 %-CI: 1.68-1.90)) was more closely associated with an increased risk of NPC, as compared to allergic rhinitis (AR) (OR of 1.60 (95 %-CI: 1.52-1.68)).

CONCLUSION

Chronic sinonasal inflammation is significantly associated with NPC in this systemic review and meta-analysis. The true cause-effect relationship and the potential effects of targeted screening need to be explored thoroughly with large scale prospective studies.

Subtype Specific Nasopharyngeal Carcinoma Incidence and Survival Trends: Differences between Endemic and Non-Endemic Populations

BACKGROUND

While nasopharyngeal carcinoma (NPC) is rare in non-endemic regions such as the North America, endemic countries, such as Thailand, continue to struggle with high incidence and mortality rates. NPC has a complex etiology that varies by histological subtype.

METHODS

NPC cases (1990-2014) were identified using the International Classification of Diseases for Oncology (ICD-O) code C11 from the Chiang Mai, Khon Kaen, Lampang, and Songkhla cancer registries and compared to Asian/Pacific Islanders (A/PI) from the US SEER program. Age-standardized incidence rates and changes in annual percent change (APC) for overall and subtype specific NPC were assessed using R and Joinpoint. Kaplan Meier curves were generated in SAS to evaluate differences in survival by sex, year of diagnosis and histological subtype. Five-year relative survival estimates were calculated between 2000-2014.

RESULTS

Non-keratinizing NPC predominated across all registries except Songkhla, where the keretinizing subtype made up ~60% of all reported cases. Incidence of keratinizing NPC significantly decreased among Chiang Mai males between 1996 and 2014 (APC:-13.0 [95%CI:-16.2, -9.6]), Songkhla females (APC:-4.0 [95%CI: -7.4, -0.5]) and males between 2006 and 2014 (APC:-15.5 [95%CI:-25.0, -4.7]), as well as A/PI females (APC:-5.1 [95%CI:-6,7, -3.4]) and males (APC: -4.8 [95%CI:-5.9, -3.7]). Non-keratinizing NPC increased among Songkhla males (APC:4.3 [95%CI:1.8, 6.9]). The keratinizing subtype exhibited the worst survival, while the non-keratinizing undifferentiated subtype had the best survival. Although US A/PI had the highest 5-year relative survival estimates, among the Thai registries Chiang Mai had the best and Lampang the worst survival.

CONCLUSION

Although US A/PIs exhibited similar rates of NPC as seen in the endemic Thai population, improved tobacco control has led to a decrease in keratinizing NPC incidence irrespective of geography. Additionally, while challenges associate with access to care may still exist among rural Thais, chemoradiation was shown to confer a survival benefit in non-keratinizing NPC treatment.

Dementia associated with nasopharyngeal carcinoma

A 56 year-old man who presented with symptoms and signs of dementia was later diagnosed as having nasopharyngeal carcinoma.

Differences in cancer gene copy number alterations between Epstein-Barr virus-positive and Epstein-Barr virus-negative nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) treatment is mainly based on clinical staging. We hypothesize that better understanding of the molecular heterogeneity of NPC can aid in better treatment decisions. Therefore, the purpose of this study was to present our exploration of cancer gene copy-number alterations (CNAs) of Epstein-Barr virus (EBV)-positive and EBV-negative NPC.

METHODS

Multiplex ligation-dependent probe amplification was applied to detect CNAs of 36 cancer genes (n = 103). Correlation between CNAs, clinicopathological features, and survival were examined.

RESULTS

The CNAs occurred significantly more in EBV-negative NPC, with PIK3CA and MCCC1 (P < .001) gain/amplification occurring more frequently. Gain/amplification of cyclin-L1 (CCNL1) and PTK2 (P < .001) predict worse disease-free survival (DFS) in EBV-positive NPC.

CONCLUSION

The EBV-positive and EBV-negative NPC show some similarities in cancer gene CNAs suggesting a common pathogenic route but also important differences possibly indicating divergence in oncogenesis. Copy number gain/amplification of CCNL1 and PTK2 are possibly good predictors of survival in EBV-positive NPC.

Infection by Epstein-Barr virus in Fes (Morocco). Prevalence and predictors of positivity in nasopharyngeal cancer

OBJECTIVES

To determine the prevalence and genotypic distribution of Epstein-Barr virus (EBV) in a sample of patients of Hassan II University Hospital (Morocco) due to nasopharyngeal pathologies and requiring a biopsy. We identified factors associated to the EBV infection.

METHODS

112 patients were recruited (January 2012-October 2014). Biopsies were conducted for the molecular diagnosis of EBV. The data collected included sociodemographic characteristics, smoking and drug abuse, medical background and histologic diagnosis. The EBV diagnosis was performed via the Polymerase Chain Reaction.

RESULTS

50% of patients were infected by EBV (98.2% with EBV type A compared to 1.8% type B). Most infected patients were ≥40years(65.5%), male (59.6%) and in unfavorable socioeconomic circumstances. 83.3% of patients with lymphoma and 69.8% of patients with nasopharyngeal carcinoma presented concomitant EBV infections. 88.9% of patients who took drugs were infected by EBV compared to 47.7% of those who did not. In the multivariate analysis, age (OR 1.03; IC95% 1.02-1.06), smoking (OR 4.28; IC95%1.24-14.78) and having a malignant process (OR 6.96; IC95% 2.26-21.44) were significantly associated with EBV.

CONCLUSIONS

Infection by EBV is related to several factors, such as advanced age, smoking, and suffering a malignant process. In subjects with malignant pathologies, positivity to EBV seems to be inferior to that found in other countries.

Haptoglobin Genotypes in Nasopharyngeal Carcinoma

Aim

Haptoglobin polymorphisms are associated with different cancers; however, the occurrence of nasopharyngeal carcinoma (NPC) in relation to haptoglobin polymorphisms has not been reported. In this study, the distribution of haptoglobin genotypes among patients with NPC was investigated and the prognostic significance of haptoglobin genotypes was further analyzed.

Material and methods

Haptoglobin genotypes were analyzed using polymerase chain reaction and electrophoresis. The genotypes were determined in the sera of 49 NPC patients and in 134 controls.

Results

The haptoglobin genotypes of patients with NPC were as follows: Hp 1–1, 2%; Hp 2–1, 39%; Hp 2–2, 59%. The frequency of the Hp 2–2 genotype was much higher in NPC patients than in control individuals (p=0.044). Furthermore, NPC patients with the Hp 2–2 genotype had advanced T stages (p=0.001) and larger primary tumor volumes (p=0.035) than those with Hp 2–1 or 1–1.

Conclusion

An increased frequency of the Hp 2–2 genotype was associated with NPC. The Hp 2 allele was also overexpressed in NPC patients. NPC patients with the Hp 2–2 genotype had advanced T stage and a larger primary tumor volume. Hp 2–2 may be a negative prognostic factor in NPC.

Incidence and Mortality of Nasopharynx Cancer and Its Relationship With Human Development Index in the World in 2012

BACKGROUND

One of the most common cancers in head and neck is nasopharynx. Knowledge about the incidence and mortality of this disease and its distribution in terms of geographical areas is necessary for further study, better planning and prevention. Therefore, this study aimed to determine the incidence and mortality of nasopharynx cancer and its relationship with human development index (HDI) in the world in 2012.

METHODS

This study was an ecological study conducted based on GLOBOCAN project of World Health Organization (WHO) for the countries in world. The correlation between standardized incidence rates (SIRs) and standardized mortality rates (SMRs) of nasopharynx cancer with HDI and its components was assessed with correlation coefficient by using SPSS 15.

RESULTS

In 2012, 86,691 nasopharynx cancer cases occurred in the world, so that 60,896 new cases were seen in men and 25,795 new cases in women (sex ratio = 2.36). SIR of the cancer was 1.2 per 100,000 (1.7 in men and 0.7 in women per 100,000) in the world. In 2012, 50,831 nasopharynx death cases occurred in the world, so that 35,756 death cases were seen in men and 15,075 death cases in women (sex ratio = 2.37). SIR of mortality from the cancer was 0.7 per 100,000 (0.7 in women and 1 in men per 100,000) in the world. The results of correlation analysis showed a negative correlation between the SIR and HDI (r = -0.037, P = 0.629), and also the results of correlation analysis showed a negative correlation between the SMR and HDI (r = -0.237, P = 0.002).

CONCLUSION

Nasopharyngeal cancer is native to Southeast Asia and the highest incidence and mortality were seen in countries with moderate and low HDI. It is suggested that studies are conducted on determining the causes of the cancer incidence and mortality in the world and the differences between various regions.

Epidemiology and Inequality in the Incidence and Mortality of Nasopharynx Cancer in Asia

OBJECTIVES

One of the most common head and neck cancers is nasopharynx cancer. Knowledge about the incidence and mortality of this disease and its distribution in terms of geographical areas is necessary for further study and better planning. Therefore, this study was conducted with the aim of determining the incidence and mortality rates of nasopharynx cancer and its relationship with the Human Development Index (HDI) in Asia in 2012.

METHODS

The aim of this ecologic study was to assess the correlation between age-specific incidence rate (ASIR) and age-specific mortality rate (ASMR) with HDI and its components, which include the following: life expectancy at birth, mean years of schooling, and gross national income per capita. Data about SIR and SMR for every Asian country for 2012 were obtained from the global cancer project. We used the correlation bivariate method for the assessment. Statistical significance was assumed if p < 0.05. All reported p values are two-sided. Statistical analyses were performed using SPSS (Version 15.0, SPSS Inc.).

RESULTS

A total of 68,272 cases (males, 71.02%; females, 28.97%; sex ratio, 2.45) and 40,530 mortalities (males, 71.63%; females, 28.36%; sex ratio, 2.52) were recorded in Asian countries in 2012. The five countries with the highest ASIR of nasopharynx cancer were Malaysia, Singapore, Indonesia, Vietnam, and Brunei, and the five countries with the highest ASMR were Indonesia, Vietnam, Singapore, Malaysia, and Brunei. The correlation between HDI and ASIR was 0.097 (p = 0.520) [0.105 in men (p = 0.488) and 0.119 in women (p = 0.901)]. The correlation between HDI and ASMR was -0.102 (p = 0.502) [-0.072 in men (p = 0.633) and -0.224 in women (p = 0.134)].

CONCLUSION

Nasopharynx cancer is native to Southeast Asia. The highest incidence and mortality rates are found in Malaysia, Singapore, Indonesia, Vietnam, and Brunei. No significant relation was found between the standardized incidence and mortality rates of nasopharynx cancer and the HDI components. Further studies are recommended in Southeast Asian countries in order to find the etiology of cancer, as well as its diagnosis and treatment.

Expression of EIF5A2 associates with poor survival of nasopharyngeal carcinoma patients treated with induction chemotherapy

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a type of head-neck cancer with a distinguishable geographic and racial distribution worldwide. Increasing evidence supports that the accumulation of additional genetic and epigenetic abnormalities is important in driving the NPC tumorigenic process. In this study, we aim to investigate the association between EIF5A2 (Eukaryotic translation initiation factor 5A2) expression status and NPC clinical outcomes.

METHODS

The expression status of EIF5A2 was investigated in the NPC tissue microarray. Tissues were from 166 NPC patients staging II-IV, collected between 1999 and 2005. All patients were administered 2-3 cycles of DDP (cisplatin) + 5-Fu (5-fluorouracil) induction therapy and then treated with a uniform conventional two-dimensional radiotherapy. Cell motility assay, tumor growth assay and cytotoxicity assay were performed on the EIF5A2 overexpressed cells and control cells. siRNA was also used in the in vitro studies.

RESULTS

Positive staining of EIF5A2 was observed in 85.4 % (105/123) informative tumor cases. Multivariate analyses demonstrated that EIF5A2 was an independent prognostic marker of poor overall survival (OS) (P = 0.041), failure-free survival (FFS) (P = 0.029), and distant failure-free survival (D-FFS) (P = 0.043) in patients with locoregionally advanced NPC patients treated with cisplatin + 5-Fu chemoradiotherapy. The forced expression of EIF5A2 in NPC cells enhanced the cells' motility and growth ability. Knock-down of EIF5A2 in NPC cells decreased the cell's motility and growth ability. Our results also demonstrated that EIF5A2 overexpression induced chemoresistance of NPC cells to 5-Fu.

CONCLUSIONS

Our findings suggested that EIF5A2 expression, as examined by immunohistochemistry, could function as an independent prognostic factor of outcomes in NPC patients with cisplatin + 5-Fu chemoradiotherapy. EIF5A2 might be a novel therapeutic target for the inhibition of NPC progress.

Has survival improved for nasopharyngeal carcinoma in the United States?

OBJECTIVE: To analyze the epidemiologic patterns and survival rates for patients with nasopharyngeal carcinoma over the last three decades.

METHODS: The National Cancer Institute (NCI) Surveillance, Epidemiology, and End Results (SEER) program tumor registries were used to identify patients with nasopharyngeal carcinoma in the United States from 1973 to 1999. Incidence and survival rates for each decade were then determined according to age, gender, race, histological type, and stage using the SEER statistical program.

RESULTS: From 1973 to 1999, 4680 cases of patients with nasopharyngeal carcinoma in the United States were sampled by the NCI/SEER database. Overall incidence rates for each decade essentially remained unchanged over time (0.7/100,000). Asians exhibited the highest incidence rates (3.0–4.2), followed by blacks (0.7–1.1) and then whites (0.4–0.7). In contrast, survival rates have gradually improved over time for all stages and histological types (35.7% 5-year survival in the 1970s vs. 44.1% in the 1980, and 51% in the 1990s). With respect to race, Asians demonstrated the best 5-year survival rate (62.9%) followed by whites (42.6%) and then blacks (36.2%). However, this may be due to histology, because Asians were also found to have a greater proportion of World Health Organization (WHO) type III cases (27.6%) in comparison to the other 2 groups (22.4% for blacks and 15% for whites).

CONCLUSIONS: Although the incidence rates of nasopharyngeal carcinoma have remained essentially unchanged in the United States in the last 3 decades, survival rates for each stage and histological subtype have exhibited considerable improvement over time. The higher survival rates in Asians may be partially attributed to the more favorable histology (type III) often seen in this group. EBM rating: B-3.

Study of single nucleotide polymorphisms of tumour necrosis factors and HSP genes in nasopharyngeal carcinoma in North East India

Nasopharyngeal carcinoma (NPC) is an epithelial tumour with a distinctive racial and geographical distribution. High incidence of NPC has been reported from China, Southeast Asia, and northeast (NE) region of India. The immune mechanism plays incredibly role in pathogenesis of NPC. Tumour necrosis factors (TNFs) and heat shock protein 70 (HSP 70) constitute significant components of innate as well as adaptive host immunity. Multi-analytical approaches including logistic regression (LR), classification and regression tree (CART) and multifactor dimensionality reduction (MDR) were applied in 120 NPC cases and 100 controls to explore high order interactions among TNF-α (-308 G>A), TNF β (+252 A>G), HSP 70-1 (+190 G>C), HSP 70-hom (+2437 T>C) genes and environmental risk factors. TNF β was identified as the primary etiological factor by all three analytical approaches. Individual analysis of results showed protective effect of TNF β GG genotype (adjusted odds ratio (OR2) = 0.27, 95 % CI = 0.125-0.611, P = 0.001), HSP 70 (+2437) CC genotype (OR2 = 0.17, 95 % CI = 0.0430.69, P = 0.013), while AG genotype of TNF β was found significantly associated with risk of NPC (OR2 = 1.97, 95 % CI = 1.019-3.83, P = 0.04). Analysis of environmental factors demonstrated association of alcohol consumption, living in mud houses and use of firewood for cooking as major risk factors for NPC. Individual haplotype association analysis showed significant risk associated with GTGA haplotype (OR = 68.61, 95 % CI = 2.47-190.37, P = 0.013) while a protective effect with CCAA and GCGA haplotypes (OR = 0.19, 95 % CI = 0.05-0.75, P = 0.019; OR = 0.01 95 % CI = 0.05-0.30, P = 0.007). The multi-analytical approaches applied in this study helped in identification of distinct gene-gene and gene-environment interactions significant in risk assessment of NPC.

Proteomic analysis of a nasopharyngeal carcinoma cell line and a nasopharyngeal epithelial cell line

BACKGROUND

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy exhibiting a strong geographic preference and a close association with Epstein-Barr virus (EBV). The aim of this study was to investigate the precise mechanism of nasopharyngeal epithelial-to-NPC tumorigenesis and to identify possible biomarkers and targets for therapy.

METHODS

Proteomic analysis was performed on the immortalized nasopharyngeal epithelial cell line NP69 and the NPC cell line C666.

RESULTS

A comparative analysis of total lysates from the cell lines using 2-D gel electrophoresis-mass spectrometry resulted in the identification of 87 different protein spots. The different proteins were grouped into 5 main categories: (i) energy production and general metabolism, (ii) adaptation/stress tolerance, (iii) cell proliferation, (iv) cell structure and (v) epithelial-mesenchymal transition. The detection of metabolism-related proteins indicated that the NPC cells relied on aerobic glycolysis, with reduced use of the citric acid cycle. Glucose uptake and lactate secretion increased in the medium of C666 compared with NP69.

CONCLUSIONS

The present study revealed that glycolysis was up-regulated in the NPC cell lines compared with nasopharyngeal epithelial cells. A number of molecules involved in metabolism were identified, and further investigations will be needed to validate these potential biomarkers or targets.

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

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

Nasopharyngeal carcinoma in Indonesia: epidemiology, incidence, signs, and symptoms at presentation

Among all head and neck (H&N) cancers, nasopharyngeal carcinoma (NPC) represents a distinct entity regarding epidemiology, clinical presentation, biological markers, carcinogenic risk factors, and prognostic factors. NPC is endemic in certain regions of the world, especially in Southeast Asia, and has a poor prognosis. In Indonesia, the recorded mean prevalence is 6.2/100 000, with 13 000 yearly new NPC cases, but otherwise little is documented on NPC in Indonesia. Here, we report on a group of 1121 NPC patients diagnosed and treated at Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia between 1996 and 2005. We studied NPC incidence among all H&N cancer cases (n=6000) observed in that period, focusing on age and gender distribution, the ethnic background of patients, and the disease etiology. We also analyzed most prevalent signs and symptoms and staging of NPC patients at first presentation. In this study population, NPC was the most frequent H&N cancer (28.4%), with a male-to-female ratio of 2.4, and was endemic in the Javanese population. Interestingly, NPC appeared to affect patients at a relatively young age (20% juvenile cases) without a bimodal age distribution. Mostly, NPC initiated in the fossa of Rosenmuller and spreaded intracranially or locally as a mass in the head. Occasionally, NPC developed at the submucosal level spreading outside the anatomic limits of the nasopharynx. At presentation, NPC associated with hearing problems, serous otitis media, tinnitus, nasal obstruction, anosmia, bleeding, difficulty in swallowing and dysphonia, and even eye symptoms with diplopia and pain. The initial diagnosis is difficult to make because early signs and symptoms of NPC are not specific to the disease. Early-age Epstein-Barr virus (EBV) infection combined with frequent exposure to environmental carcinogenic co-factors is suggested to cause NPC development. Undifferentiated NPC is the most frequent histological type and is closely associated with EBV. Expression of the EBV-encoded latent membrane protein 1(LMP1) oncogene in biopsy material was compared between NPC patients of <30 years old and those of ≥30 years old, matched for sex and tumor stage. Higher LMP1 expression in patients of <30 years old was observed, which was related to more locoregional progressivity. Increased medical awareness of prevailing early stage signs and symptoms coupled to use of EBV-related diagnostic tumor markers may lead to down-staging and timely treatment to improve survival of patients with this aggressive disease.

Suppression of nasopharyngeal carcinoma cell by targeting β-catenin signaling pathway

AIM

To investigate the role of β-catenin in pathogenesis of nasopharyngeal carcinoma (NPC).

METHODS

Cellular proliferation, apoptosis, matrix penetration assay, and western blotting were employed to determine cell biological changes in NPC cell lines transfected with β-catenin siRNA. Immunohistochemistry staining was used to detect β-catenin and Ki-67 expression in NPC tissue.

RESULTS

β-Catenin was upregulated in NPC cell lines and tissues compared with chronic nasopharyngitis tissue. β-Catenin knockdown dramatically inhibited cellular growth, migration and invasion, but induced apoptosis of NPC cells. Further study showed that downstream genes of β-catenin signaling pathway including cyclin D1, c-Myc, MMP2 and MMP9 expression were suppressed in NPC cell lines transfected with β-catenin siRNA.

CONCLUSION

Targeting β-catenin signaling pathway may be a noval strategy for NPC therapy.

Early detection of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a unique disease with a clinical presentation, epidemiology, and histopathology differing from other squamous cell carcinomas of the head and neck. NPC is an Epstein-Barr virus-associated malignancy with a marked racial and geographic distribution. Specifically, it is highly prevalent in southern China, Southeast Asia, and the Middle East. To date, most NPC patients have been diagnosed in the advanced stage, but the treatment results for advanced NPC are not satisfactory. This paper provides a brief overview regarding NPC, with the focus on the early detection of initial and recurrent NPC lesions.

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.

Incidence of nasopharyngeal carcinoma in Chinese immigrants, compared with Chinese in China and South East Asia: review

Objectives:

To evaluate the literature and to compare published data on age-standardised incidence rates of nasopharyngeal carcinoma in Chinese people living in and outside China.

Design:

Systematic review of incidence rate studies and statistical incidence data concerning nasopharyngeal carcinoma in Chinese populations from 1960 to 2008.

Data sources:

Sixteen papers were identified from the PubMed, Embase and Scopus electronic databases and from a hand search of the reference lists of the retrieved papers. Further searches for raw data on age-specific and age-standardised incidence rates of nasopharyngeal carcinoma were conducted. Textbooks on relevant subjects were referred to for background information. A total of 19 papers met the inclusion criteria.

Results:

Seven studies included raw data on age-specific and age-standardised incidence rates of nasopharyngeal carcinoma in Chinese people. Twelve other studies reported on changes in the incidence of nasopharyngeal carcinoma in Chinese populations in selected countries or regions. Studies on age-specific and age-standardised rates obtained data from individual registries. Studies on incidence rates obtained data from hospital records, cancer notifications (from all sections of the medical profession), pathology records and death certificates. The results showed a decline in age-standardised incidence rates of nasopharyngeal carcinoma in Chinese immigrant populations, compared with Chinese people in China. There was also a trend towards decreasing incidence the further the population had immigrated. Thus, the incidence of nasopharyngeal carcinoma in Singaporean Chinese was higher than that in Hawaiian Chinese, and that in Hawaiian Chinese was higher than that in Californian Chinese.

Conclusion:

This review found a decreasing trend in the incidence of nasopharyngeal carcinoma in Chinese migrants living in countries with a low risk of the disease.

Alcohol consumption and the risk of nasopharyngeal carcinoma: a systematic review

The evidence concerning the influence of alcohol drinking on the risk of nasopharyngeal carcinoma (NPC) has yielded intriguing findings but has lacked a clear-cut interpretation due to inconsistencies. To unify this body of evidence, we performed a systematic review. With funding and using a protocol developed by the World Cancer Research Fund (WCRF), 15 bibliographic databases were searched for epidemiological studies that reported a measure of association between alcoholic beverage consumption and NPC. Pooled odds ratios (ORs) for highest-vs.-lowest categories of total alcohol intake was obtained by using an inverse-variance weighted random-effects model. A dose-response trend was examined in models using generalized least square estimation. The search identified 14 case-control studies from 5 countries. For total alcohol intake, the pooled ORs in a comparison of the highest to the lowest category was 1.33 (95% CI: = 1.09-1.62) in 11 studies. Data from 6 studies indicated a J-shape dose-response trend, with NPC risk decreasing with up to 15 drinks/wk and increasing with higher intake. Fewer data were available to assess the associations between NPC and intake of beer, wine, and spirits. The potential J-shaped dose-response trend suggests a reduced risk of NPC related to the light alcohol drinking, an observation that warrants further study. Considered in total, the quantitative summaries of the case-control evidence suggest that heavy alcohol consumption is associated with an increased risk of NPC.

Nasopharyngeal carcinoma--review of the molecular mechanisms of tumorigenesis

Nasopharyngeal carcinoma (NPC) is a head and neck cancer rare throughout most of the world but common in certain geographic areas, such as southern Asia. While environmental factors and genetic susceptibility play important roles in NPC pathogenesis, the Epstein-Barr virus in particular has been implicated in the molecular abnormalities leading to NPC. There is upregulation of cellular proliferation pathways such as the Akt pathway, mitogen-activated protein kinases, and the Wnt pathway. Cell adhesion is compromised due to abnormal E-cadherin and beta-catenin function. Aberrations in cell cycle are due to dysregulation of factors such as p16, cyclin D1, and cyclin E. Anti-apoptotic mechanisms are also upregulated. There are multiple abnormalities unique to NPC that are potential targets for novel treatments.

Secular trends of nasopharyngeal carcinoma incidence in Singapore, Hong Kong and Los Angeles Chinese populations, 1973-1997

Nasopharyngeal carcinoma (NPC) is a rare cancer in most parts of world, but rather common in Southern China and Southeast Asia. This study used IARC published datasets to explore the secular trends of incidence rates of NPC among different Chinese populations in Singapore, Hong Kong and Los Angeles, over the time period 1973-1997. We observed great disparity in the risks and time trends of NPC in those selected Chinese populations. The highest risk was in Hong Kong where the incidence rates have declined rapidly throughout the whole study period in both males and females. For Singapore Chinese, the incidence rates also dropped recently in both genders, but the low incidence rates in Los Angeles Chinese have remained essentially unchanged over time. We further assessed the contribution of period and cohort effects to the observed trends in Hong Kong and Singapore populations through age-period-cohort modeling and found that an age-cohort model provided the best fit to the data in both populations, although for Singapore females a simple age-drift model fit the data well. There was a statistically significant decrease in the drop in incidence of NPC for cohorts born around 1940 in Hong Kong and 1958 in Singapore. This indicates that environmental and lifestyle changes play an important role in the declining incidence of NPC over time.

The enigmatic epidemiology of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) has a unique and complex etiology that is not completely understood. Although NPC is rare in most populations, it is a leading form of cancer in a few well-defined populations, including natives of southern China, Southeast Asia, the Arctic, and the Middle East/North Africa. The distinctive racial/ethnic and geographic distribution of NPC worldwide suggests that both environmental factors and genetic traits contribute to its development. This review aims to summarize the current knowledge regarding the epidemiology of NPC and to propose new avenues of research that could help illuminate the causes and ultimately the prevention of this remarkable disease. Well-established risk factors for NPC include elevated antibody titers against the Epstein-Barr virus, consumption of salt-preserved fish, a family history of NPC, and certain human leukocyte antigen class I genotypes. Consumption of other preserved foods, tobacco smoking, and a history of chronic respiratory tract conditions may be associated with elevated NPC risk, whereas consumption of fresh fruits and vegetables and other human leukocyte antigen genotypes may be associated with decreased risk. Evidence for a causal role of various inhalants, herbal medicines, and occupational exposures is inconsistent. Other than dietary modification, no concrete preventive measures for NPC exist. Given the unresolved gaps in understanding of NPC, there is a clear need for large-scale, population-based molecular epidemiologic studies to elucidate how environmental, viral, and genetic factors interact in both the development and the prevention of this disease.

Trends in the incidence rates of nasopharyngeal carcinoma among Chinese Americans living in Los Angeles County and the San Francisco metropolitan area, 1992-2002

Nasopharyngeal carcinoma is much more common in Asian countries than in Western countries. However, since the 1980s, nasopharyngeal carcinoma incidence has fallen among both men and women in Hong Kong, and recently a similar trend has also been noted in Singapore. Using data from the Surveillance, Epidemiology, and End Results Program and the US Census, the authors evaluated recent trends in the incidence rates of nasopharyngeal carcinoma among Chinese living in Los Angeles County and in the San Francisco-Oakland (California) metropolitan area. From 1992 to 2002, the rates of nasopharyngeal carcinoma in these two populations decreased in men by 37% (95% confidence interval: -54, -12) but in women by just 1% (95% confidence interval: -40, 64). In Chinese men, the overall decline in incidence was limited primarily to a decline in the rate of type I tumors (differentiated squamous tumors with keratin production). While the reasons underlying the observed patterns of incidence remain to be determined, changes in lifestyle and environment are likely to be contributory factors.

Epidemiology of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world, with an incidence well under 1 per 100,000 person-years. Exceptions are the Chinese, especially the Cantonese living in the central region of Guangdong Province in Southern China. Other populations with elevated rates include the natives of Southeast Asia, the natives of the Artic region, and the Arabs of North Africa and parts of the Middle East. Intake of preserved foods at an early age has been linked to NPC risk in all population groups with increased NPC rates. Other recognized risk factors for NPC are cigarette smoking, and occupational exposure to formaldehyde and wood dust.

Familial nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) has a striking geographical and ethnical distribution. It occurs with high frequency in southern China and Southeast Asia. Family clustering was also observed in NPC and a typical family with 15 NPC cases was introduced in this paper. Epidemiological and genetic studies have been carried out in the previous decades and vast information was accumulated for familiar NPC, in terms of risk factors, inheritance mode, and involvement of gene polymorphisms. The major findings in this field were summarized. Furthermore, future directions leading to understanding the genetic mechanism of the familial form of NPC was also discussed.

Study of human leukocyte antigen class I phenotypes in Moroccan patients with nasopharyngeal carcinoma

Previous reports demonstrated an association between the human leukocyte antigen (HLA) and risk for nasopharyngeal carcinoma (NPC) among the Chinese in Singapore, a population with a high incidence of this malignancy. In our study, we assess the association between HLA and NPC in Morocco, a median-prevalence area for this cancer, where NPC presents the particularity of also affecting young individuals. Using the standard microlympho-cytotoxicity test, we typed a total of 154 Moroccan NPC patients and 257 unrelated healthy controls for their HLA-A and B antigens. The results of these analyses show that the frequencies of HLA-A10, HLA-B13 and HLA-B18 were found to be higher in the NPC group than in the control group, whereas HLA-A9 was associated with a decreased risk. After correction for the number of specificities tested, these differences were statistically significant only for HLA-B18 (corrected p value [pc] < 0.023, relative risk [RR] = 4.14) and HLA-A9 (pc < 0.023, RR = 0.45). The comparison of the distribution of the HLA antigens in younger and older cohorts of patients shows that the incidence of HLA-A10 and HLA- B18 was higher in the older group, whereas the frequencies of HLA-A19 and HLA-B13 were significantly higher in younger patients compared with controls. The presence of both HLA-A19 and HLA-B13 phenotypes correlated with an increased risk of developing NPC among overall patients compared with controls. According to the sex distribution, increased frequency of HLA-B18 was found in male and female NPC patients compared with controls, whereas the frequency of HLA-A10 was higher only in male NPC patients compared with controls.

The aetiology of nasopharyngeal carcinoma

Nasopharyngeal carcinoma is a disease with a remarkable racial and geographical distribution. In most parts of the world it is a rare condition and in only a handful of places does this low risk profile alter. These include the Southern Chinese, Eskimos and other Arctic natives, inhabitants of South-East Asia and also the populations of North Africa and Kuwait.

Epstein-barr virus-associated malignancies: epidemiologic patterns and etiologic implications

Epstein-Barr virus (EBV), a ubiquitous B-lymphotrophic herpesvirus, has been found in the tumor cells of a heterogeneous group of malignancies (Burkitt's lymphoma, lymphomas associated with immunosuppression, other non-Hodgkin's lymphomas, Hodgkin's disease, nasopharyngeal carcinoma, gastric adenocarcinoma, lymphoepithelioma-like carcinomas, and immunodeficiency-related leiomyosarcoma). As the epidemiologic characteristics of these cancers have not been considered together, this review seeks to relate their incidence patterns and risk factors to EBV biology and virus-host interaction in an attempt to help elucidate factors involved in EBV-related carcinogenesis. We include a brief review of EBV virology and primary infection to provide a biologic context for considering the epidemiology, summarize the most salient epidemiologic features of each malignancy, synthesize epidemiologic data by risk factor to uncover commonalities and informative contrasts across the diseases, and propose hypotheses regarding etiologic mechanisms, based on the possible effect of the risk factors at various stages in the viral life cycle.

Preserved foods in relation to risk of nasopharyngeal carcinoma in Shanghai, China

A population-based case-control study was conducted in Shanghai, China, to investigate the association between dietary factors and risk of nasopharyngeal carcinoma (NPC). The study included 935 NPC patients aged 15 to 74 years and 1,032 community controls. Exposures to salted fish and other protein-containing preserved food were associated with increased risk of NPC. Individuals who ate salted fish at least once a week had an 80% increase in risk of NPC relative to those who ate salted fish less than once a month (p = 0.07). Compared with those in the lowest quartile of protein-containing preserved foods, subjects in the highest quartile of intake experienced a statistically significant 78% increase in risk of NPC [odds ratio (OR) = 1.78, 95% confidence interval (CI) = 1.37-2.31], with a dose-dependent relationship (p for linear trend < 0.001 ). A similar association between intake of preserved vegetables and NPC risk was observed (OR = 1.39, p for linear trend = 0.003). In contrast, high intake of oranges/tangerines was associated with a statistically significant reduction in risk of NPC (OR = 0.55, p for linear trend < 0.001). When we examined the joint effect of preserved food and oranges/tangerines on risk of NPC, subjects in the highest tertile of preserved food and the lowest tertile of orange/ tangerine intake had a 3-fold increase in risk (95% CI = 2.08-4.91) compared with those in the lowest tertile of preserved food and the highest tertile of orange/tangerine intake.

Cancer mortality in East and Southeast Asian migrants to New South Wales, Australia, 1975-1995

Routinely collected data for New South Wales were used to analyse cancer mortality in migrants born in East or Southeast Asia according to duration of residence in Australia. A case-control approach compared deaths from cancer at particular sites with deaths from all other cancers, adjusting for age, sex and calendar period. Compared with the Australian-born, these Asian migrants had a 30-fold higher risk of dying from nasopharyngeal cancer in the first 2 decades of residence, falling to ninefold after 30 years, and for deaths from liver cancer, a 12-fold risk in the first 2 decades, falling to threefold after 30 years. The initial lower risk from colorectal, breast or prostate cancers later converged towards the Australian-born level, the change being apparent in the third decade after migration. The relative risk of dying from lung cancer among these Asian migrants was above unity for each category of duration of stay for women, but at or below unity for men, with no trend in risk over time. An environmental or lifestyle influence for nasopharyngeal and liver cancers is suggested as well as for cancers of colon/rectum, breast and prostate.

A molecular study of EBV DNA and p53 mutations in nasopharyngeal carcinoma of Saudi Arab patients

Tumor biopsies obtained from 25 Saudi Arab patients with nasopharyngeal carcinoma (NPC) were examined for the presence of Epstein-Barr virus (EBV) DNA detected by the polymerase chain reaction (PCR) and for the incidence of p53 mutations screened by a combination of PCR, single strand conformation polymorphism (SSCP) and PCR-restriction fragment length polymorphism (PCR-RFLP). DNA sequencing was carried out to confirm the occurrence of p53 mutation. While 92% of the tumor specimens were found to carry EBV DNA, only 1/25 showed the incidence of a homozygous mutation at codon 248 of the p53 gene. The data showed that despite a high association of EBV infection with Saudi NPC, the frequency of p53 mutations was very low. Our results are consistent with the worldwide observation of infrequent p53 mutations in NPC.

Tobacco use and nasopharyngeal carcinoma in a cohort of US veterans

The risk of nasopharyngeal carcinoma (NPC), a relatively rare neoplasm in the United States, was examined in relation to tobacco use in a cohort of nearly 250,000 US veterans whose mortality experience was followed for 26 years. A total of 48 NPC deaths were identified during the follow-up period. Current smokers had a nearly 4-fold increase in risk of NPC compared with non-users of any tobacco, with risk increasing to 6.4 among those smoking more than 2 packs daily. After adjustment for age and number of cigarettes smoked, risks were inversely associated with age at starting to smoke, with the highest risk observed among those who started smoking before age 15, although no clear trend associated with duration of smoking was observed. Former cigarette smokers had a small excess risk of NPC, but no association was detected for cigar/pipe users. This study adds strong evidence to the increasing literature linking cigarette smoking to NPC.

Familial nasopharyngeal carcinoma in patients who are not Chinese

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a malignancy that is prominent in Cantonese Chinese people. It is presumed to result from an interaction of genetic and environmental factors, including the Epstein-Barr virus (EBV). In an attempt to further clarify the pathogenesis of this disease, an evaluation of NPC occurring in racial/ethnic groups not considered susceptible to this disease could be informative.

METHODS

A white family with NPC occurring in three siblings was investigated and information was gleaned from literature on other reports of familial NPC in non-Chinese families.

RESULTS

In the family being investigated, another genetically determined disease, hemophilia, was identified. Radiation early in life was noted to be a possible risk factor for NPC in the proband. A review of familial NPC in the white population revealed that in contrast to sporadic NPC, which is usually of the well-differentiated type, familial NPC usually is poorly differentiated.

CONCLUSIONS

Familial NPC offers an important opportunity to investigate the etiology of this disease. With newer laboratory techniques to investigate pathogenetic mechanisms, detailed evaluations of non-Chinese NPC families may become increasingly important.

Diet and nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a disease with a remarkable racial and geographical distribution. It is very rare (incidence of less than 1 per 100,000 person-years) in most parts of the world and only a handful of populations are known to deviate from this low-risk profile, which include people of southern China. Eskimos and other natives of the Arctic region, natives of southeast Asia, and mainly Arab populations of north Africa and Kuwait. There is now convincing evidence implicating dietary factors as the primary cause of NPC among Chinese. A series of case-control studies conducted in various Chinese populations with distinct risks of NPC, ranging from the very high-risk Cantonese to the relatively low-risk Northern Chinese, have suggested that ingestion of salted fish and other kinds of preserved foods by the Chinese constitutes the most important cause of NPC development among these people. Preliminary data on Malays in southeast Asia, Eskimos in Alaska, and Arabs of north Africa also suggest that ingestion of preserved foods by these population groups may be responsible for their raised incidence of NPC.

Occupational and other non-dietary risk factors for nasopharyngeal carcinoma in Guangzhou, China

We conducted interviews on 306 histologically confirmed incident cases of nasopharyngeal carcinoma (NPC) occurring in residents of Guangzhou City, China, who were under the age of 50, and an equal number of age-, sex-, and neighborhood-matched controls. We also interviewed 110 mothers of patients under 45 and 139 mothers of controls who were matched to patients under age 45, to obtain information on childhood exposures of study subjects. Occupational exposure to products of combustion (RR = 2.4, p = 0.001) and cotton dust (RR = 0.3, P = 0.01) was independently related to risk of NPC. Use of tobacco products showed a moderate association with NPC; a lifetime exposure of 30+ pack-year equivalents conferred a 2-fold increased risk. A history of chronic ear or nose condition (rhinitis, sinusitis, nasal polyp, otitis media) was another risk factor for NPC (RR = 2.2, p less than 0.0005), and 18 cases compared to 3 controls had a first-degree relative with NPC (RR = 6.0, p = 0.001).

Induction of malignant nasal cavity tumours in Wistar rats fed Chinese salted fish

Epidemiological evidence has implicated Chinese salted fish as a human nasopharyngeal carcinogen. In the present study, 221 Wistar-Kyoto rats aged 21 days were randomly assigned to one of three experimental groups. Rats in group 1 (high dose group) were fed a powder diet of one part Chinese salted fish to three parts certified rat chow during the first 18 months. Similarly, rats in group 2 (low dose group) were fed a powder diet of one part salted fish to five parts rat chow for 18 months. Rats in group 3 were given rat chow only throughout the 3-year experiment. Four malignant tumours of the nasal cavity were observed among rats fed the experimental diets (three and one respectively in the high and low dose groups). No comparable tumours were observed in controls, compatible with the historical control rate of zero. Our results, therefore, further strengthen the hypothesis that Chinese salted fish is a human nasopharyngeal carcinogen; they also establish Wistar rats as a viable animal model for carcinogenicity studies of this food in the laboratory.

Diet and nasopharyngeal carcinoma: a case-control study in Guangzhou, China

We conducted interviews on 306 histologically confirmed incident cases of nasopharyngeal carcinoma (NPC) occurring in residents of Guangzhou City, China, who were under the age of 50 years, and an equal number of age-, sex-, and neighborhood-matched controls. We also interviewed 110 mothers of patients under age 45 years and 139 mothers of controls who were matched to patients under age 45 years, to obtain information on childhood exposures of study subjects. Exposure to salted fish, whether in adulthood or in childhood, was significantly associated with an increased risk of NPC. The association was strongest for exposure during weaning, and exposures at all other periods were no longer related to NPC risk after adjustment for exposure during weaning. Besides salted fish, childhood exposure to 5 other preserved foods (fermented fish sauce, salted shrimp paste, moldy bean curd, and 2 kinds of preserved plum) was significantly related to NPC, and the effects were independent of salted fish exposure. Finally, cases ingested significantly less fresh vegetables and fruits than controls, especially during early childhood, and the differences were not explained by their differing consumption pattern of salted fish and other preserved foods.

Patterns of nasopharyngeal cancer mortality in the United States

We examined the geographic pattern of nasopharyngeal cancer (NP cancer) mortality in the United States using economic sub-regions (ESRs) as the basis for analysis. The distribution of 15,145 deaths from NP cancer over the years 1950-1979 revealed clustering in the 119 ESRs that was not detected in analyses of distribution by the 48 states, 506 state economic areas or 3,056 counties or combinations of counties of the coterminous United States. NP cancer mortality among white males was concentrated on the south-east Atlantic and Gulf coasts. This newly described pattern is not due to any recent changes in mortality rates and should provide leads to further epidemiologic study.

Cigarette smoking and nasopharyngeal carcinoma

A case-control study was undertaken to investigate possible etiologic factors in nasopharyngeal cancer, a rare tumor in the United States. Data from 39 nasopharyngeal cancer cases and the same number of matched controls showed significantly more cases born in Asia than controls, supporting the notion that exposure in early life has a prolonged carcinogenic effect. Cases also smoked significantly more cigarettes than controls, indicating a need for investigating the role of cigarette smoking and other exposures in the etiology of nasopharyngeal cancer in western countries.

Salted fish and nasopharyngeal carcinoma in Malaysia

The evidence for a hypothesis that eating salted fish is associated with nasopharyngeal carcinoma (NPC) is reviewed. The hypothesis was tested among Malaysian Chinese using a matched case-control design. The kinds of salted fish and patterns of use were also investigated in a control group comprising 100 Chinese, 50 Malay and 50 Indian households. During 1980, in Selangor, Malaysia, interviews with 100 Chinese cases of NPC and 100 non-disease controls indicated that salted fish consumption during childhood was a significant risk (relative risk = 3.0, P = 0.04), with an elevated risk for daily as opposed to less frequent consumption. Salted fish consumption during adolescence was a less significant risk, and current consumption not at all. There were 19 kinds of fishes reported as being eaten as salted fish by the 200 control households. There were marked differences between ethnic groups in preference for different kinds: Chinese preferred red snapper (74% of households), Malay jewfish (54%) and Indian red snapper (28%). Salted fish was hardly ever eaten daily by any household; weekly was a moderate frequency in all ethnic groups; less than weekly most common. There were no statistically significant differences between Chinese NPC case and non-disease control participants in kind of salted fish eaten. Results were the same when the data were analyzed by sex, subethnic group and income.