CYP2E1 polymorphisms and nasopharyngeal carcinoma risk: a meta-analysis

Epidemiology of nasopharyngeal carcinoma: current insights and future outlook

Nasopharyngeal carcinoma (NPC) is characterised by its remarkable geographical and ethnic distribution. The interplay between genetic susceptibility, environmental exposures, and Epstein-Barr virus (EBV) infections is indicated in the development of NPC. Exposure to tobacco smoking, dietary factors, and inhalants has been associated with the risk of NPC. Genetic association studies have revealed NPC-associated susceptibility loci, including genes involved in immune responses, xenobiotic metabolism, genome maintenance, and cell cycle regulation. EBV exposure timing and strain variation might play a role in its carcinogenicity, although further investigations are required. Other factors including medical history and oral hygiene have been implicated in NPC. Prevention strategies, including primary prevention and secondary prevention through early detection, are vital in reducing mortality and morbidity of NPC. The current review discusses the global and regional distribution of NPC incidences, the risk factors associated with NPC, and the public health implications of these insights. Future investigations should consider international, large-scale prospective studies to elucidate the mechanisms underlying NPC pathogenesis and develop individualized interventions for NPC.

Nasopharyngeal carcinoma: current views on the tumor microenvironment's impact on drug resistance and clinical outcomes

The incidence of nasopharyngeal carcinoma (NPC) exhibits significant variations across different ethnic groups and geographical regions, with Southeast Asia and North Africa being endemic areas. Of note, Epstein-Barr virus (EBV) infection is closely associated with almost all of the undifferentiated NPC cases. Over the past three decades, radiation therapy and chemotherapy have formed the cornerstone of NPC treatment. However, recent advancements in immunotherapy have introduced a range of promising approaches for managing NPC. In light of these developments, it has become evident that a deeper understanding of the tumor microenvironment (TME) is crucial. The TME serves a dual function, acting as a promoter of tumorigenesis while also orchestrating immunosuppression, thereby facilitating cancer progression and enabling immune evasion. Consequently, a comprehensive comprehension of the TME and its intricate involvement in the initiation, progression, and metastasis of NPC is imperative for the development of effective anticancer drugs. Moreover, given the complexity of TME and the inter-patient heterogeneity, personalized treatment should be designed to maximize therapeutic efficacy and circumvent drug resistance. This review aims to provide an in-depth exploration of the TME within the context of EBV-induced NPC, with a particular emphasis on its pivotal role in regulating intercellular communication and shaping treatment responses. Additionally, the review offers a concise summary of drug resistance mechanisms and potential strategies for their reversal, specifically in relation to chemoradiation therapy, targeted therapy, and immunotherapy. Furthermore, recent advances in clinical trials pertaining to NPC are also discussed.

Associations between serum trace elements and the risk of nasopharyngeal carcinoma: a multi-center case-control study in Guangdong Province, southern China

Background

Associations between trace elements and nasopharyngeal carcinoma (NPC) have been speculated but not thoroughly examined.

Methods

This study registered a total of 225 newly diagnosed patients with NPC and 225 healthy controls matched by sex and age from three municipal hospitals in Guangdong Province, southern China between 2011 and 2015. Information was collected by questionnaire on the demographic characteristics and other possibly confounding lifestyle factors. Eight trace elements and the level of Epstein-Barr virus (EBV) antibody were measured in casual (spot) serum specimens by inductively coupled plasma-mass spectrometry (ICP-MS) and enzyme-linked immunosorbent assay (ELISA), respectively. Restricted cubic splines and conditional logistic regression were applied to assess the relationship between trace elements and NPC risk through single-and multiple-elements models.

Results

Serum levels of chromium (Cr), cobalt (Co), nickel (Ni), arsenic (As), strontium (Sr) and molybdenum (Mo) were not associated with NPC risk. Manganese (Mn) and cadmium (Cd) were positively associated with NPC risk in both single-and multiple-element models, with ORs of the highest tertile compared with the reference categories 3.90 (95% CI, 1.27 to 7.34) for Mn and 2.30 (95% CI, 1.26 to 3.38) for Cd. Restricted cubic splines showed that there was a linear increasing trend between Mn and NPC risk, while for Cd there was a J-type correlation.

Conclusion

Serum levels of Cd and Mn was positively related with NPC risk. Prospective researches on the associations of the two trace elements with NPC ought to be taken into account within the future.

Feature Reviews of the Molecular Mechanisms of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is rare in most parts of the world but endemic in southern Asia. Here, we describe the molecular abnormalities in NPC and point out potential molecular mechanisms for future therapy. This article provides a brief up-to-date review focusing on the molecular pathways of NPC, which may improve our knowledge of this disease, and we also highlight some issues for further research. In brief, some heritable genes are related to NPC; therefore, people with a family history of NPC have an increased risk of this disease. Carcinogenic substances and Epstein-Barr virus (EBV) exposure both contribute to tumorigenesis through the accumulation of multiple genomic changes. In recent years, salted fish intake has decreased the impact on NPC, which implies that changing exposure to carcinogens can modify the risk of NPC. Eradication of cancer-associated viruses potentially eradicates cancer, and EBV vaccines might also prevent this disease in the future. Screening patients by using an EBV antibody is feasible in the high-risk group; plasma EBV DNA measurement could also be conducted for screening, prognosis, and monitoring of this disease. Understanding the molecular mechanisms of NPC can further provide novel information for health promotion, disease screening, and precision cancer treatment.

Identification of key pseudogenes in nasopharyngeal carcinoma based on RNA-Seq analysis

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a malignant head and neck tumor, and more than 70% of new cases are in East and Southeast Asia. However, association between NPC and pseudogenes playing important roles in genesis of multiple tumor types is still not clear and needs to be investigated.

METHODS

Using RNA-Sequencing (RNA-seq) technology, we analyzed pseudogene expression in 13 primary NPC and 6 recurrent NPC samples as well as their paracancerous counterparts. Quantitative PCR was used to validate the differentially expressed pseudogenes.

RESULTS

We found 251 differentially expressed pseudogenes including 73 up-regulated and 178 down-regulated ones between primary NPC and paracancerous tissues. Enrichment analysis of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were conducted to filter out the key pseudogenes. We reported that pseudogenes from cytochrome P450 (CYP) family, such as CYP2F2P, CYP2G1P, CYP4F24P, CYP2B7P and CYP2G2P were significantly down-regulated in NPC compared to paracancerous tissues, while IGHV1OR15-2, IGHV3-11, FCGR1CP and IGHV3-69-1 belonging to Fc gamma receptors were significantly up-regulated. CYP2B7P, CYP2F2P and CYP4F26P were enriched in arachidonic acid metabolism pathway. The qRT-PCR analysis validated the lower expression of pseudogenes CYP2F2P and CYP2B7P in NPC tissues and cell lines compared to paracancerous tissues and normal human nasopharyngeal epithelial cell line. CYP2B7P overexpression weakened migratory and invasive capacity of NPC cell line. Moreover, the expression pattern of those pseudogenes in recurrent NPC tissues was different from the primary NPC.

CONCLUSION

This study suggested the role of pseudogenes in tumorigenesis and progression, potentially functioning as therapeutic targets to NPC.

The Evolving Epidemiology of Nasopharyngeal Carcinoma

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

IMPACT

New epidemiologic findings have reshaped the causal model for NPC.

Clinicopathological and prognostic features of nasopharyngeal carcinoma in children and adolescents: A retrospective study of 196 cases in South China

Nasopharyngeal carcinoma (NPC) occurring in children and adolescence is extremely rare and till present there is a lack of understanding on their clinicopathological and prognostic features of this rare entity. For our study, data of 196 cases children and adolescents with NPC from the past 18 years at a high-volume cancer center from South China were retrospectively analyzed. Half of the evaluated NPC patients (83/166, 50.0%) were staged as Stage IVa disease, whereas 1.2% (2/166), 27.7% (46/166), 16.9% (28/166) and 4.2% (7/166) had Stage II, III, IVb and IVc disease, respectively. Serum EBV EA-IgA ≥1:10 and VCA-IgA ≥1:40 were found in 67.7% (113/167) and 76.6% (128/167) of the evaluated patients, respectively, whereas 56.8% (84/148) of the patients had plasma EBV DNA ≥1000 copies/mL. Histologically, all tumors were classified as nonkeratinizing squamous cell carcinoma (NK-SCC). Immunohistochemistrically, the expression of CK (AE1/AE3), P63, CK5/6 and P40 were observed in 100% (88/88), 93.2% (68/73), 84.1% (58/69) and 63.2% (12/19) of the detected cases, respectively. All cases show similar immunophenotype compared to that occurring in adult patients. All evaluated cases (71/71 100%) harbored EBER. Patients with plasma EBV DNA ≥1000 copies/mL and positive serum EBV antibodies had significantly inferior 3-year OS (88% vs 100%, P = .007) compared to other corresponding groups. The combination of EBV serology and plasma EBV DNA are useful to predict the outcome of patients with NPC in children and adolescents.

Polymorphisms of CYP2E1 rs2031920 is not Associated with Risk of Nasopharyngeal Carcinoma in Minangkabau Ethnic Group

BACKGROUND:

Various environmental factors have been suspected to be associated with the risk of developing Nasopharyngeal Carcinoma (NPC). Volatile nitrosamines found in salted fish are thought to be carcinogenic substances for NPC. Nitrosamines are activated by the CYP2E1 enzyme. Several studies investigated the relationship between polymorphism in the CYP2E1 gene and susceptibility to NPC, but the results obtained were inconsistent.

AIM:

This study was conducted to analyze the association of the CYP2E1 rs2031920 polymorphisms with the incidence of NPC in the Minangkabau ethnic group.

METHODS:

The subjects of this study were newly diagnosed NPC Minangkabau ethnic patients, while the controls were healthy people. A total of 23 cases of NPC and 23 aged (± 3 years) and sex-matched controls participated in the study. The method used to identify these polymorphisms is PCR sequencing.

RESULTS:

On recent study we found CYP2E1 rs2031920 gene polymorphism in both the NPC and control groups, in the NPC group there were 8.7% heterozygote mutants while in the control group there were 26.1% heterozygote mutants, and there were no homozygote mutants in the two groups, and statistically none a significant relationship between CYP2E1 gene polymorphism and the incidence of NPC, with p > 0.05.

CONCLUSION:

Our study reveals that there is no association of CYP2E1 gene polymorphism (rs2031920) with the incidence of nasopharyngeal carcinoma in the Minangkabau ethnic group.

Analysis of the role of rs2031920 and rs3813867 polymorphisms within the cytochrome P450 2E1 gene in the risk of squamous cell carcinoma

Background

To explore the genetic effect of rs2031920 and rs3813867 polymorphisms within the cytochrome P450 2E1 (CYP2E1) gene on the risk of squamous cell carcinoma (SCC), a meta-analysis was performed.

Methods

The eligible case–control studies were obtained by database searching and screening, and the specific statistical analysis was performed with STATA 12.0 software.

Results

After the process of database searching and screening, a total of 32 case–control studies with 7435 cases and 10,466 controls were ultimately included in our meta-analysis. With regard to the rs2031920 C/T polymorphism, in comparison to controls, a reduced risk in cases of esophageal squamous cell carcinoma (ESCC) was detected for the models of allele T vs. allele C [P = 0.025, odds ratio (OR) = 0.67], carrier T vs. carrier C (P = 0.014, OR = 0.70), TT vs. CC (P = 0.029, OR = 0.65), CT vs. CC (P = 0.040, OR = 0.56), CT + TT vs. CC (P = 0.035, OR = 0.58). Similarly, a decreased SCC risk was observed for the rs3813867 G/C polymorphism in the allele, carrier, homozygote, dominant, and recessive models of overall SCC meta-analysis and “ESCC” subgroup analysis (all P < 0.05, OR < 1) and in all genetic models of “Asian” and “population-based control (PB)” subgroup analysis (all P < 0.05, OR < 1). Additionally, for the rs2031920/rs3813867 haplotype, a decreased SCC risk was also detected in the overall SCC meta-analysis under the allele, carrier, homozygote and dominant model (all P < 0.05, OR < 1) and the subgroup analysis of “PB” under the allele, carrier, and dominant models (all P < 0.05, OR < 1).

Conclusions

Our meta-analysis supports the “T” allele carrier of the CYP2E1 rs2031920 C/T polymorphism and “C” allele carrier of the rs3813867 G/C polymorphism as protective factors for ESCC patients, especially in Asian populations.