Genetic Risk Markers for Nasopharyngeal Carcinoma in Portugal: Tumor Necrosis Factor Alpha −308G >A Polymorphism

The association between COX-2 gene rs5275 polymorphism and Nasopharyngeal carcinoma risk

The overexpression of cyclooxygenase-2 (COX-2) was correlated with the invasion and lymphatic metastasis and with the clinical stage of Nasopharyngeal carcinoma (NPC). The C allele of COX-2 gene rs5275 polymorphism disrupts miR-542-3p function to promote COX-2 overexpression. To examine the role of COX-2 gene rs5275 polymorphism in NPC, we determined COX-2 gene rs5275 polymorphism by using a custom-by-design 48-Plex single nucleotide polymorphism (SNP) Scan^™ Kit. We found that C allele or CC genotype of rs5275 polymorphism in COX-2 gene was associated with an increased risk of NPC. In stratified analyses, COX-2 gene rs5275 polymorphism was associated with the risk of NPC among females, smokers, and drinkers. Based on these results, we concluded that COX-2 gene rs5275 variant contributes to NPC risk in a Chinese population. Larger studies with more diverse ethnic populations are needed to confirm these results.

No association of TNF-α-308G/A polymorphisms with head and neck cancer risk: A PRISMA-compliant meta-analysis

BACKGROUND

A number of studies had reported the association between tumor necrosis factor-alpha (TNF-α) gene polymorphisms and head and neck cancer (HNC) risk. However, the results remained controversial. Therefore, we performed a meta-analysis to derive a more precise evaluation of the association between TNF-α-308G/A polymorphism and overall HNC risk and evaluated influence of cancer types and ethnicities.

METHODS

A systematic literature search was performed using Pubmed, Embase, Cochrane Library, and Web of science. In total, we identified 15 studies including 2005 cancer cases and 2876 controls to evaluate the association of TNF-α-308G/A polymorphism with risk for HNC.

RESULTS

Overall, there was no significant association between TNF-α-308G/A polymorphism and the risk of HNC. Furthermore, subgroup analyses were performed according to the types of tumor and the ethnicities, we also found there was no significant association between TNF-α-308G/A polymorphism and the risk of NPC and OC, and European and Asian populations had no statistically significant difference in the relationship of TNF-α-308G/A polymorphism and HNC susceptibility.

CONCLUSION

This meta-analysis indicates that the TNF-α-308G/A polymorphism is not associated with HNC risk. In the future, large and well-designed case-control studies are needed to validate our findings.

Lack of Associations between TNF-αPolymorphisms and Cervical Cancer in Thai women

The risk of developing cervical cancer in women infected with human papillomavirus (HPV) may be influenced by an individual's genetic susceptibility. Published data linking single nucleotide polymorphisms (SNPs) in the tumor necrosis factor-alpha (TNF-?) promoter region at positions -308G>A (rs1800629) and -238G>A (rs361525) to cervical cancer risk have been inconclusive. In this study, we examined 251 cervical specimens and classified them into two groups according to their cytological findings: 121 cancer cases and 130 controls (low-grade squamous intraepithelial lesion and normal cytology). All specimens were typed by PCR and sequencing for TNF-αpromoter -308G>A (rs1800629) and -238G>A (rs361525). The genotype distribution of SNPs in either rs1800629 or rs361525 did not significantly demonstrate higher frequency in the cancer group (p=0.621 and p=0.68, respectively). Based on these results, neither the TNF-αpromoter -308G>A (rs1800629) nor the -238G>A (rs361525) polymorphism presents a major risk factor for cervical cancer among Thai women. Larger studies are necessary to elucidate possible genetic mechanisms influencing cervical cancer development.

5'UTR +24T>C CR2 is not associated with nasopharyngeal carcinoma development in the North Region of Portugal

OBJECTIVE

We have analysed the association of the +24T>C polymorphism (rs3813946) in CR2, the cellular receptor for Epstein-Barr virus (EBV), in the susceptibility for the development of nasopharyngeal carcinoma (NPC).

METHODS

A retrospective case-control study was developed with peripheral blood samples from 111 individuals with NPC and 608 healthy individuals (controls) from the North region of Portugal. The genotyping analysis was performed by allelic discrimination real-time PCR using a TaqMan(®) SNP Genotyping Assay.

RESULTS

The genotype distribution was 62.2% TT, 34.2% TC and 3.6% CC for NPC patients; and 65.0%, 30.6% and 4.4%, respectively, for controls. Our study showed no statistical association between the genotype distribution in controls and all types of NPC (P = 0.717); nevertheless, the analysis showed statistically significant differences (P = 0.038) regarding cases with well- or moderately differentiated types of NPC suggesting that +24CC/CT genotypes are associated with increased risk (OR = 4.16; 95% CI 1.28-15.7; P = 0.016).

CONCLUSIONS

This is the first study in Western populations to characterize the association of the CR2 +24T>C polymorphism in NPC development, and our results suggest that more studies are required to clarify the impact on NPC susceptibility in different populations.

Polymorphisms in host immune response associated genes and risk of nasopharyngeal carcinoma development in Portugal

BACKGROUND

Host genetic susceptibility markers in immune response associated genes may contribute to identify individuals with high risk of developing viral infection and viral-associated cancers. We aimed to characterize different polymorphisms in immune response associated genes and evaluate its association with nasopharyngeal carcinoma (NPC) development.

METHODS

We have developed a hospital-based case-control study selecting 134 patients with NPC (cases) and 732 healthy individuals (controls) from the Northern Region of Portugal. Eight single nucleotide polymorphisms (SNP) were selected: -56C>T IFNGR1 (rs2234711), +4854G>T IL1A (rs17561), +3954C>T IL1B (rs1143634), +1902A>G IL4RA (rs1801275), -1082G>A IL10 (rs1800896), +2018T>C IL1RN (rs419598), HLA-A locus A>T (rs2530388), HCGA9 locus A>T (rs6457110). All polymorphisms were analysed by real-time methodology using TaqMan(®) SNP Genotyping Assays.

RESULTS

The overall analysis revealed no statistical significant differences between genotypes distributions in all of studied polymorphisms (p>0.05). However, the results for HCGA9 rs6457110 polymorphism showed a tendency for an increased risk of NPC development among TT carriers with an almost of 2-fold increased risk (OR=1.86; 95%CI 1.00-3.65).

CONCLUSIONS

This is the first study to characterize these polymorphisms in NPC patients in Portugal. Our study indicates that HCGA9 rs6457110 polymorphism might represent a risk marker for NPC development in our population and that other SNPs should be further studied in larger populations to clarify the evidences. This data reinforces the need for more studies, especially in NPC low-prevalent populations.

The interplay of host genetic factors and Epstein-Barr virus in the development of nasopharyngeal carcinoma

The interplay between host cell genetics and Epstein-Barr virus (EBV) infection contributes to the development of nasopharyngeal carcinoma (NPC). Understanding the host genetic and epigenetic alterations and the influence of EBV on cell signaling and host gene regulation will aid in understanding the molecular pathogenesis of NPC and provide useful biomarkers and targets for diagnosis and therapy. In this review, we provide an update of the oncogenes and tumor suppressor genes associated with NPC, as well as genes associated with NPC risk including those involved in carcinogen detoxification and DNA repair. We also describe the importance of host genetics that govern the human leukocyte antigen (HLA) complex and immune responses, and we describe the impact of EBV infection on host cell signaling changes and epigenetic regulation of gene expression. High-power genomic sequencing approaches are needed to elucidate the genetic basis for inherited susceptibility to NPC and to identify the genes and pathways driving its molecular pathogenesis.

Interleukin-10-1082 gene polymorphism is associated with papillary thyroid cancer

The etiopathogenesis of thyroid cancer has not been clearly elucidated although the role of chronical inflammation and the imbalance between pro- and anti-inflammatory cytokines may play a role in the etiology. The aim of the present study was to investigate whether cytokine gene polymorphisms are associated with papillary thyroid cancer (PTC), and to evaluate the relationship between genotypes and clinical/laboratory manifestation of PTC. Tumor necrosis factorα (TNFα) G-308A (rs 1800629), interleukin-6 (IL-6) G-174C (rs 1800795) and IL-10 A-1082G (rs 1800896) single nucleotide polymorphisms in DNA from peripheral blood leukocytes of 190 patients with thyroid cancer and 216 healthy controls were investigated by real-time PCR combined with melting curve analysis. There was no notable risk for PTC afflicted by TNFα-308 and IL-6-174 alone. However, IL-10-1082 G allele frequency were higher among PTC patients than healthy controls (p=0.009). The patients with IL-10-1082 GG geotype have twofold increased risk of developing thyroid cancer according to AA genotype (OR 2.07, 95% CI 1.21-3.55). In addition, the concomitant presence of IL-10-1082 G allele (GG+AG genotypes) together with IL-6 -174 GG genotype has a nearly twofold increased risk for thyroid cancer (OR 1.75 with 95% CI 1.00-3.05, p=0.049). We suggest that IL-10-1082 G allele is associated with an increased risk of PTC. The polymorphism of IL-10 gene can improve our knowledge about the pathogenesis of PTC, and could provide to estimate people at the increased risk for PTC.

IL-1RN VNTR polymorphism as a susceptibility marker for nasopharyngeal carcinoma in Portugal

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a rare malignancy in Western countries that is widely associated with the infection by Epstein-Barr virus (EBV). Several studies have showed that a common allele (allele 2) of the 86-bp variable number of tandem repeats (VNTR) polymorphism within intron 2 of the interleukin 1 receptor antagonist (IL-1RN) gene is associated with several disorders, including viral-associated cancers.

METHODS

We have developed a hospital-based case-control study to characterise the role of the IL-1RN 86-bp VNTR polymorphism in the development of NPC with 112 patients with the disease and 433 healthy individuals from the northern region of Portugal. IL-1RN genotypes were combined according to the number of repeats: allele 2 (A2), the short allele that corresponds to two repeats, and L, the long allele that corresponds to three or more repeats.

RESULTS

Our study revealed that 31.2% of NPC patients were IL-1RN A2*A2, compared with 9.7% observed in the control group. The statistical analysis revealed that IL-1RN*A2 homozygosity for the A2 allele was associated with a fourfold increased risk for NPC development (p<0.001). Additionally, cumulative hazard analysis revealed that estimated median age of onset of NPC is significantly (p<0.001) different for A2*A2 homozygous versus non-A2*A2 (57.0 vs. 74.0, respectively).

CONCLUSIONS

This is the first study to evaluate the role of the IL-1RN VNTR in NPC development in Portugal. Our study indicates IL-1RN*A2 homozygosity as a significant risk marker in our population and that it should be further investigated for the potential role in the definition of a susceptibility profile for NPC onset.

TNF-α-308G/A polymorphisms and nasopharyngeal cancer risk: a meta-analysis

Previous evidence has indicated that the polymorphism of tumor necrosis factor-alpha (TNF-α) is a risk factor for various cancers, however, the association between TNF-α-308G/A polymorphism and nasopharyngeal carcinoma (NPC) remains controversial and ambiguous. The aim of this study is to clarify the association between TNF-α polymorphism and NPC using meta-analysis. A meta-analysis based on five eligible case-control studies involving 499 cases and 1,470 controls was carried out to summarize the data on the association between TNF-α-308G/A polymorphism and NPC risk. Odds ratios (OR) with 95 % confidence intervals (95 % CI) were used to assess the strength of this association in the fixed-effect model. The pooled analyses showed no significant association between TNF-α-308G/A polymorphism and NPC (AA vs. GG: OR = 1.38, P = 0.193; GA vs. GG: OR = 0.92, P = 0.585; GA + AA vs. GG: OR = 1.00, P = 0.972; AA vs. GA + GG: OR = 1.44, P = 0.138). We also categorized by geographic location (non-Asian or Asian) for subgroup analysis; the results also showed no significant association between TNF-α-308G/A polymorphism and NPC risk in all of the comparisons. No publication bias was observed in this study (t = -0.11, P = 0.918, 95 % CI = -4.893-4.559). No significant association was found between TNF-α-308G/A polymorphism and the risk for NPC.

DNA repair system and prostate cancer progression: the role of NBS1 polymorphism (rs1805794)

NBS1 plays an important role in the maintenance of genomic integrity, by being involved in cellular response to DNA damage. The NBS1 rs1805794 G>C polymorphism has been investigated in several studies, but its function still remains unclear due to some controversial results. The present work aimed to evaluate the role of this polymorphism in prostate cancer progression, by performing a case-control study comparing 239 patients who were diagnosed with early disease to 186 who presented advanced disease. We also assessed NBS1 mRNA expression among the different groups by quantitative real time (qRT)-polymerase chain reaction. We found that the GG carriers presented an almost two fold increased risk for advanced prostate disease (odds ratio [OR] = 1.87; confidence interval [CI] = 1.26-2.79; p = 0.002). Further, high tumor grade (OR = 3.02; CI = 2.32-3.92; p<0.001) and high serum prostate specific antigen (PSA) (OR = 6.48; CI = 4.48-9.38; p<0.001) were consistently associated to advanced disease. Regarding NBS1 mRNA expression, we did not find any association with the different outcomes nor genotypes (p = 0.926; p = 0.894, respectively). Our results suggest for the first time that rs1805794 GG genotype appears to be associated with a higher risk for advanced prostate cancer, thus, suggesting a possible new role for NBS1 in prostate cancer progression.

Cytokine and chemokine modification by Toll-like receptor polymorphisms is associated with nasopharyngeal carcinoma

Toll-like receptors (TLR) play a pivotal role in sensing a wide range of pathogens, including bacteria, fungi and viruses. A dysregulation of TLR signaling may increase the risk of developing chronic inflammatory diseases and cancers. The aim of this study was to investigate the association of TLR2 R753Q, TLR4 D299G, and T399I polymorphisms with nasopharyngeal carcinoma (NPC) and to explore the effects of these polymorphisms on cytokine and chemokine expression in NPC biopsies. The genotypes of the three loci among 236 patients with NPC and 287 healthy controls were determined by PCR-RFLP. Cytokines and chemokines mRNA and protein in NPC biopsies were measured by real-time quantitative PCR and ELISA, respectively. Results showed that the combined CT/TT genotype of T399I was associated with increased NPC risk, with an odds ratio of 1.853 (95% confidence interval: 1.184-2.961). Also, individuals with the T allele of T399I showed a 1.842-fold increase in NPC risk compared to those with the T399I C allele (95% confidence interval: 1.213-3.015). Messenger RNA levels of interleukin (IL)-1α, tumor necrosis factor-α and IL-10 were significantly elevated in patients with T399I combined CT/TT genotype; IL-1α and IL-10 protein concentration significantly increased in NPC patients with T399I combined CT/TT genotype compared to those with the T399I CC genotype. Our data suggest that TLR4 T399I modify cytokines and chemokines patterns and play a role in the development of NPC.

Familial and large-scale case-control studies identify genes associated with nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy and has a remarkable geographic distribution, which is highly prevalent in southern China, Southeast Asia, and North Africa. Although most of the NPC are sporadic cases, the familial clustering of NPC has been demonstrated worldwide. Accumulating studies have proposed that the etiology of NPC is multi-stage and multi-factorial, involving genetic lesions, Epstein-Barr virus infection, and environmental exposure. Genetic variations result in differences in gene function, which in turn lead to different susceptibility to disease. Many studies have been carried out to dissect the genetic variants that contribute to NPC susceptibility. This article reviews the current progress of genetic studies to identify genes associated with NPC, focusing on the familial linkage and large-scale case-control study designs.

Genetic predisposition factors and nasopharyngeal carcinoma risk: a review of epidemiological association studies, 2000-2011: Rosetta Stone for NPC: genetics, viral infection, and other environmental factors

While infection with Epstein-Barr virus (EBV) is known to be an essential risk factor for the development of nasopharyngeal carcinoma (NPC), other co-factors including genetic factors are thought to play an important role. In this review, we summarize association studies conducted over the past decade to evaluate the role of genetic polymorphisms in NPC development. A review of the literature identified close to 100 studies, including 3 genome-wide association studies (GWAS), since 2000 that evaluated genetic polymorphisms and NPC risk in at least 100 NPC cases and 100 controls. Consistent evidence for associations were reported for a handful of genes, including immune-related HLA Class I genes, DNA repair gene RAD51L1, cell cycle control genes MDM2 and TP53, and cell adhesion/migration gene MMP2. However, for most of the genes evaluated, there was no effort to replicate findings and studies were largely modest in size, typically consisting of no more than a few hundred cases and controls. The small size of most studies, and the lack of attempts at replication have limited progress in understanding the genetics of NPC. Moving forward, if we are to advance our understanding of genetic factors involved in the development of NPC, and of the impact of gene-gene and gene-environment interations in the development of this disease, consortial efforts that pool across multiple, well-designed and coordinated efforts will most likely be required.

Genetic polymorphisms and cervical cancer development: ATM G5557A and p53bp1 C1236G

Persistent infections by high-risk types of human papillomavirus (HPV) have been established as the etiological agent of cervical cancer. The integration of the HPV genome into the host genome is a crucial step in cervical carcinogenesis, although, correct activation of DNA damage repair pathways will avoid the development of cancer. Recent data indicate that several polymorphisms of key regulators from the DNA damage repair pathway (i.e. 53BP1 and ATM) are associated with cancer development susceptibility. We have developed a hospital-based retrospective study considering 429 cervical specimens from women with different cervical lesions including invasive carcinoma. This study aimed to evaluate the role of the ATM D1853N (5557G>A) and 53bp1 D353E (1236C>G) polymorphisms in the development of cervical cancer, using TaqMan SNP Genotyping Assays. Statistical analysis revealed that ATM 5557GG homozygous individuals (OR=1.94; p=0.044) are at increased risk of developing LSIL, while for the 53BP1 1236C>G polymorphism no association was found. Nevertheless, we observed a tendency for an increased risk of LSIL in 53BP1 1236C allele carriers (OR=1.63; p=0.069). Logistic regression adjusted for age revealed no significant differences from the non-adjusted analysis. This is the first study to evaluate the role of ATM G5557A and P53BP1 C1236G polymorphisms in cervical cancer susceptibility. This study reveals a possible trend of both polymorphisms for a genetic susceptibility pattern of cervical cancer development. Hence, our results may be of interest for future understanding of the progression of cervical cancer.