Insulin-like growth factor binding protein 7 (IGFBP7) functions mostly independent of the IGF signaling pathway and acts as a tumor suppressor in multiple cancers, but roles of IGFBP7 genetic variants in cancer remains unknown. In a hospital-based study of 1,065 patients with squamous cell carcinoma of head and neck (SCCHN) and 1,112 cancer-free controls of non-Hispanic whites, we investigated associations between two putatively functional IGFBP7 promoter single nucleotide polymorphisms (SNPs) (−702G>C, rs11573014 and −418G>A, rs4075349) and SCCHN risk. A significantly lower SCCHN risk was observed in those subjects carrying −418AG (adjusted OR=0.82, 95% CI=0.67–0.99) and −418AG+AA (adjusted OR=0.82, 95% CI=0.69–0.99) genotypes than those carrying the −418GG genotype, but not for the −702G>C SNP. However, those subjects carrying two common homozygous genotypes of these two SNPs (−418GG and −702GG) had an increased risk (adjusted OR=1.21, 95% CI=1.00-0.1.46) than did those carrying variant genotypes (−418AG+AA and −702CG+CC). This increased risk was more evident in subgroups of never smokers and subjects with oral cancer. Further functional analysis showed that the IGFBP7 −418A allele had significantly higher promoter and DNA-protein binding activities than did the G allele, suggesting a tumor suppressor role of this allelic change in the SCCHN etiology. We conclude that the functional variant −418 G>C in the IGFBP7 promoter is associated with reduced risk of SCCHN, likely by enhancing the IGFBP7 promoter and DNA-protein binding activities. Larger studies are needed to validate our findings.
IGFBP7; case-control study; tumor suppressor gene; head and neck cancer; promoter polymorphism
Human DEC1 (deleted in esophageal cancer 1) gene is located on chromosome 9q, a region frequently deleted in various types of human cancers, including squamous cell carcinoma of the head and neck (SCCHN). However, only one epidemiological study has evaluated the association between DEC1 polymorphisms and cancer risk. In this hospital-based case–control study, four potentially functional single-nucleotide polymorphisms −1628 G>A (rs1591420), −606 T>C [rs4978620, in complete linkage disequilibrium with −249T>C (rs2012775) and −122 G>A(rs2012566)], c.179 C>T p.Ala60Val (rs2269700) and 3′ untranslated region-rs3750505 as well as the TP53 tumor suppressor gene codon 72 (Arg72Pro, rs1042522) polymorphism were genotyped in 1111 non-Hispanic Whites SCCHN patients and 1130 age-and sex-matched cancer-free controls. After adjustment for age, sex and smoking and drinking status, the variant −606CC (i.e. −249CC) homozygotes had a significantly reduced SCCHN risk (adjusted odds ratio = 0.71, 95% confidence interval = 0.52–0.99) compared with the −606TT homozygotes. Stratification analyses showed that a reduced risk associated with the −606CC genotype was more pronounced in subgroups of non-smokers, non-drinkers, younger subjects (defined as ≤57 years), carriers of the TP53 Arg/Arg (rs1042522) genotype, patients with oropharyngeal cancer or late-stage SCCHN. Further in silico analysis revealed that the −249 T-to-C change led to a gain of a transcription factor-binding site. Additional functional analysis showed that the −249T-to-C change significantly enhanced transcriptional activity of the DEC1 promoter and the DNA–protein-binding activity. We conclude that the DEC1 promoter −249 T>C (rs2012775) polymorphism is functional, modulating susceptibility to SCCHN among non-Hispanic Whites.
The cooperation between phorbol 12-myristate 13-acetate induced protein 1 (NOXA) and myeloid cell leukemia 1 (MCL1) is critical in the intrinsic apoptotic pathway. Human papillomavirus 16 (HPV16), by inducing p53 and pRb-E2F degradation, may play an essential role in development of squamous cell carcinoma of the head and neck (SCCHN) through NOXA-MCL1 axis-mediated apoptosis. Therefore, genetic variants of NOXA and MCL1 may modify the SCCHN risk associated with HPV16 seropositivity.
HPV16 serology was obtained by immunoadsorption assay. Four functional SNPs in the promoter of NOXA (rs9957673, rs4558496) and MCL1 (rs9803935, rs3738485) were genotyped for 380 cases and 335 frequency-matched cancer-free controls of non-Hispanic whites.
Associations between the four polymorphisms and SCCHN risk were not significant, while we observed a significantly joint effect on SCCHN risk between the polymorphisms and HPV16 seropositivity. Notably, this effect modification was particularly pronounced for oropharyngeal cancer in subgroups including never smokers, never drinkers and younger subjects.
Our results suggested that polymorphisms of NOXA and MCL1 may modify the risk of HPV16-associated oropharyngeal cancer. The further identification of population subgroups at higher risk provides evidence that HPV-targeting treatment may help benefit SCCHN. However, larger studies are needed to validate our findings.
NOXA; MCL1; HPV16; Genetic susceptibility; Squamous cell carcinoma of the head and neck
Xeroderma pigmentosum group G (XPG) protein is essential for the nucleotide excision repair (NER) system, and genetic variations in XPG/ERCC5 that affect DNA repair capacity may contribute to the risk of tobacco-induced cancers, including squamous cell carcinoma of the head and neck (SCCHN). We investigated the association between XPG/ERCC5 polymorphisms and risk of squamous cell carcinoma of the head and neck (SCCHN).
We genotyped 12 tagging and potentially functional single nucleotide polymorphisms (SNPs) of XPG/ERCC5 in a case-control study of 1,059 non-Hispanic white patients with SCCHN and 1,066 cancer-free age-and sex matched controls and evaluated their associations with SCCHN risk.
Multivariate logistic regression showed that only an intronic tagging SNP (rs4150351A/C) of XPG/ERCC5 was associated with a decreased risk of SCCHN (adjusted OR=0.76, 95% CI=0.62–0.92 for AC vs. AA; adjusted OR=0.81, 95% CI=0.67–0.98 for AC/CC vs. AA), but this association was nonsignificnant after corrections by the permutation test (empirical P=0.105). In the genotype-phenotype correlation analysis using peripheral lymphocytes from 44 SCCHN patients, we found that rs4150351 AC/CC was associated with a statistically significant increase in XPG/ERCC5 mRNA expression.
These findings suggest that genetic variation in XPG/ERCC5 may not affect the SCCHN risk, although rs4150351 C variant genotypes were associated with the increased expression of XPG/ERCC5 mRNA and nonsignificantly decreased risk of SCCHN. Larger population-based and additional functional studies are warranted to validate our findings.
ERCC5; polymorphism; SCCHN; risk
P53 up-regulated modulator of apoptosis (PUMA) is a critical factor in the intrinsic apoptotic pathway. Through PUMA-dependent mechanisms, human papillomavirus 16 (HPV16) oncoprotein may affect apoptosis by E6-mediated p53 degradation. To examine whether the PUMA variants modify the association between HPV16 serology and risk of squamous cell carcinoma of the head and neck (SCCHN), we genotyped two polymorphisms in the PUMA promoter (rs3810294 and rs2032809) in 380 cases and 335 cancer-free controls of non-Hispanic whites, who were frequency-matched by age (± 5 years), sex, smoking and drinking status. We found that each individual polymorphism had only a modest impact on risk of SCCHN, particularly in oropharyngeal cancer for rs3810294 and non-oropharyngeal cancer for rs2032809. After we stratified the individuals by HPV16 serology, and used those with the corresponding common homozygous genotype and HPV16 seronegativity as the reference group, for each polymorphism we found that the risk of SCCHN associated with HPV16 seropositivity was higher among those with variant genotypes than those with the corresponding common homozygous genotype. Notably, this effect modification was particularly pronounced in several subgroups including never smokers, never drinkers, younger patients, and patients with oropharyngeal cancer. Furthermore, we also characterized the functional relevance of the two polymorphisms to explore the genotype-phenotype correlation. Our results suggested that the PUMA promoter polymorphisms may be a biomarker for risk of HPV16-associated SCCHN, particularly in never smokers, never drinkers, younger patients, and patients with oropharyngeal cancer. Larger studies are needed to validate our findings.
PUMA polymorphisms; HPV16; genetic susceptibility; molecular epidemiology; squamous cell carcinoma of the head and neck
Methylating agents are involved in carcinogenesis, and the DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) removes methyl group from O6-methylguanine. Genetic variation in DNA repair genes has been shown to contribute to susceptibility to squamous cell carcinoma of the head and neck (SCCHN). We hypothesize that MGMT polymorphisms are associated with risk of SCCHN. In a hospital-based case-control study of 721 patients with SCCHN and 1,234 cancer-free controls frequency-matched by age, sex and ethnicity, we genotyped four MGMT polymorphisms, two in exon 3, 16196C>T and 16286C>T and two in the promoter region, 45996G>T and 46346C>A. We found that none of these polymorphisms alone had a significant effect on risk of SCCHN. However, when these four polymorphisms were evaluated together by the number of putative risk genotypes (i.e. 16195CC, 16286CC, 45996GT+TT, and 46346CA+AA), a statistically significantly increased risk of SCCHN was associated with the combined genotypes with three to four risk genotypes, compared with those with zero to two risk genotypes [adjusted odds ratio (OR) = 1.27; 95% confidence interval (CI) = 1.05-1.53]. This increased risk was also more pronounced among young subjects (OR = 1.81; 95% CI = 1.11-2.96), men (OR = 1.24; 95% CI = 1.00-1.55), ever smokers (OR = 1.25; 95% = 1.01-1.56), ever drinkers (OR = 1.29; 95% CI = 1.04-1.60), patients with oropharyngeal cancer (OR = 1.45; 95% CI = 1.12-1.87), and oropharyngeal cancer with regional lymph node metastasis (OR = 1.52; 95% CI = 1.16-2.01). In conclusion, our results suggest that any one of MGMT variants may not have a substantial effect on SCCHN risk, but a joint effect of several MGMT variants may contribute to risk and progression of SCCHN, particularly for oropharyngeal cancer, in non-Hispanic whites.
oral cancer; DNA repair; methylation; genetic susceptibility; molecular epidemiology
Phospholipase C epsilon 1 (PLCE1) (an effector of Ras) belonging to the phospholipase family plays crucial roles in carcinogenesis and progression of several cancers, including squamous cell carcinoma of the head and neck (SCCHN). A single nucleotide polymorphism (SNP, rs2274223) in PLCE1 has been identified as a novel susceptibility locus in genome-wide association studies (GWAS) of esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA) that share similar risk factors with SCCHN. Therefore, we investigated the association between potentially functional SNPs in PLCE1 and susceptibility to SCCHN.
We genotyped three potentially functional SNPs (rs2274223A/G, rs3203713A/G and rs11599672T/G) of PLCE1 in 1,098 SCCHN patients and 1,090 controls matched by age and sex in a non-Hispanic white population.
Although none of three SNPs was alone significantly associated with overall risk of SCCHN, their combined effects of risk alleles (rs2274223G, rs3203713G and rs11599672G) were found to be associated with risk of SCCHN in a locus-dose effect manner (Ptrend = 0.046), particularly for non-oropharyngeal tumors (Ptrend = 0.017); specifically, rs2274223 was associated with a significantly increased risk (AG vs. AA: adjusted OR = 1.29, 95% CI = 1.01-1.64; AG/GG vs. AA: adjusted OR = 1.30, 95% CI = 1.03-1.64), while rs11599672 was associated with a significantly decreased risk (GG vs. TT: adjusted OR = 0.54, 95% CI = 0.34-0.86; TG/GG vs. TT: adjusted OR = 0.76, 95% CI = 0.61-0.95).
Our findings suggest that PLCE1 variants may have an effect on risk of SCCHN associated with tobacco and alcohol exposure, particularly for those tumors arising at non-oropharyngeal sites. These findings, although need to be validated by larger studies, are consistent with those in esophageal and gastric cancers.
PLCE1; polymorphism; SCCHN; risk; susceptibility
Recent studies reported associations of the relative telomere length (RTL) and TERT variants with risk of several cancers, which has not been comprehensively investigated in squamous cell carcinoma of the head and neck (SCCHN).
We detected RTL in peripheral blood lymphocytes and genotyped six selected functional single nucleotide polymorphisms (SNPs) of the TERT gene in 888 SCCHN cases and 885 cancer-free controls of non-Hispanic whites.
Overall, we did not observe significant associations between RTL and SCCHN risk (adjusted OR, 0.97; 95% CI, 0.80–1.17 for below versus above the median; Ptrend = 0.618) nor between the six TERT SNPs and SCCHN risk. We also found no associations between RTL and TERT SNPs.
Our results suggest that RTL and TERT functional polymorphisms may not play a major role in the etiology of SCCHN. Large prospective studies are needed to validate our findings.
Although our results suggest no association among RTL, TERT functional polymorphisms, and SCCHN risk, this study may contribute to future meta-analysis.
genetic polymorphisms; Telomere length; TERT; head and neck cancer; molecular epidemiology
Mouse double minute 4 (MDM4), a homolog of MDM2, is a key negative regulator of p53, and its amplification or over-expression contributes to carcinogenesis by inhibiting the p53 tumor suppressor activity. We investigated the association between MDM4 polymorphisms and risk of squamous cell carcinoma of the head and neck (SCCHN).
We genotyped three MDM4 tagging polymorphisms, two in the 3′ untranslated region (3′ UTR: rs11801299G>A and rs10900598G>T) and one in intron 1 (rs1380576C>G), in a case-control study of 1,075 non-Hispanic white SCCHN patients and 1,084 cancer-free controls and evaluated their associations with SCCHN risk.
Although none of these three polymorphisms individually had a statistically significant effect on risk of SCCHN, nor did their combined number of putative risk genotypes (i.e., rs11801299GG, rs1380576CG+GG, and rs10900598GG) (OR = 1.16 and 95% CI=0.93–1.45), we found that individuals with 1–3 risk genotypes had statistically significantly increased risk of oropharyngeal cancer (OR = 1.32 and 95% CI = 1.00–1.73), particularly for those with T1–2 stage (OR = 1.40; 95% CI = 1.02–1.94), those with regional lymph node metastases (N1–3) (OR = 1.44; 95% CI = 1.07–1.95), and those with late stages (III and IV) (OR = 1.34; 95% CI = 1.01–1.77).
Our results suggest that the joint effect of MDM4 variants may contribute to the risk of oropharyngeal cancer in non-Hispanic whites. Additional studies are warranted to unravel whether the particular stage distribution of oropharyngeal cancer with the strongest association (T1–2, N1–3, and III–IV) is a possible link with human papillomavirus-related oropharyngeal cancers.
MDM4 polymorphism; case-control; genetic susceptibility; molecular epidemiology; head and neck neoplasms; oropharyngeal cancer
DNA-methyltransferase-3B (DNMT3B) may play an oncogenic role during tumorigenesis, and its genetic variants have been reportedly to be associated with risk of several cancers, but few studies have investigated their roles in head and neck cancer. Here we report a hospital-based case-control study with 832 SCCHN patients and 843 cancer-free controls of non-Hispanic whites that evaluated the association between two DNMT3B single nucleotide polymorphisms (SNPs) DNMT3B-149C>T (rs2424913) and DNMT3B-579G>T (rs2424909) in the promoter region and risk of squamous cell carcinoma of the head and neck (SCCHN). We found that compared with C-allele carriers, the DNMT3B-149 TT genotype was statistically significantly associated with increased risk of SCCHN (adjusted OR, 1.35, 95% CI, 1.01-1.80, P = 0.043), whereas the DNMT3B-579 TT genotype showed only a non-statistically significant risk compared with G-allele carriers. Further analysis of the effects of combined genotypes suggested that subjects with either DNMT3B-149 TT or DNMT3B-579 TT homozygous genotypes had statistically significantly increased risk of SCCHN (adjusted OR = 1.36, 95% CI = 1.07-1.73, P = 0.013). Stratification analysis showed a more profound risk in the subgroups of the young (≤57 years, the median age of the controls), males, current smokers, current drinkers, and patients with primary tumor sites of pharynx and larynx. This large study provides reliable risk estimates for associations between DNMT3B variants and SCCHN risk in non-Hispanic whites, and our findings are consistent with that of previously reported cancer case-control studies of other cancers. Further mechanistic studies are needed to unravel the underlying molecular mechanisms.
Polymorphism; Methylation; DNMT3B; Molecular epidemiology; Cancer risk
p73 interacts with the HPV16 oncoproteins E6 and E7, and p73 variation may modify the interaction between p73 protein and HPV16 oncogenic proteins and contribute to cellular malignant transformation.
In this case-case comparison study, we analyzed HPV16 status in tumor specimens and genotyped the p73 G4C14-to-A4T14 polymorphism using genomic DNA from blood of 202 non-Hispanic white patients with squamous cell carcinoma of the Head and Neck (SCCHN). We calculated odds ratio (OR) and 95% confidence intervals (CIs) in univariate and multivariable logistic regression models to examine the association between the p73 polymorphism and HPV16 status in SCCHN.
Compared with the p73 GC/GC genotype, the AT/AT and combined GC/AT + AT/AT variant genotypes were significantly associated with tumor HPV16 positivity among SCCHN patients (adjusted OR = 5.32; 95% CI, 1.32-21.4 and adjusted OR = 1.91; 95% CI, 1.03-3.53, respectively). There was a significant dose-effect relationship between the AT allele and tumor HPV16-positive status in SCCHN patients (trend test: P = .014). Moreover, the stratified analyses showed that the association between tumor HPV16-positive status and the combined p73 GC/AT+AT/AT genotypes was more pronounced among several subgroups of patients who were older, male, ever drinkers, and those with oropharyngeal cancer.
The p73 polymorphism was associated with HPV16 status in SCCHN and may serve as a marker for tumor HPV16 positivity in patients with SCCHN, particularly those with oropharyngeal cancer.
p73 polymorphism; genetic susceptibility; HPV; squamous cell carcinoma of the head and neck; molecular epidemiology
Single-nucleotide polymorphisms (SNPs) of TERT-rs2736098 (C > T) and CLPTM1L-rs401681(C > T) at the 5p15.33 locus are significantly associated with cancer risk as reported in genome-wide association studies (GWAS), but there are no reported studies for squamous cell carcinoma of the head and neck (SCCHN). In a case–control study of 1079 SCCHN cases and 1115 cancer-free controls of non-Hispanic whites who were frequency matched by age and sex, we genotyped for these two SNPs and assessed their associations with SCCHN risk. Compared with the CC genotypes of each polymorphism, the associations of a slightly reduced risk of SCCHN with the variant genotypes of CT + TT of both polymorphisms were approaching statistical significance [Odds ratio (OR) = 0.90, 95% confidence interval (CI) = 0.76–1.08 for TERT-rs2736098 and OR = 0.86, 95% CI = 0.71–1.04 for CLPTM1L-rs401681, respectively]. When the two SNPs were combined, the variant genotypes of the two SNPs were significantly associated a moderately reduced risk of SCCHN (OR = 0.82, 95% CI = 0.67–0.99), and the number of variant genotypes was associated with a significantly reduced risk in a dose–response manner (P = 0.028). Furthermore, the reduced risk was more pronounced in ever smokers, ever drinkers and patients with oropharyngeal cancer. Our results suggested that these two SNPs at the 5p15.33 locus may be associated with a reduced risk of SCCHN, particularly for their combined effect. Although we added additional evidence for the association of the two SNPs with cancer risk as reported in GWAS, additional studies are needed to replicate our findings.
Caspase-3 plays a central role in executing cell apoptosis and thus in carcinogenesis, but little is known about the role of CASP3 variants in susceptibility to squamous cell carcinoma of the head and neck (SCCHN).
Genotype and haplotypes of the first intron (rs4647601:G>T and rs4647602:C>A) and 5′-UTR (rs4647603:G>A) regions of CASP3 (NT_022792.17) were determined for 930 SCCHN patients and 993 cancer-free controls in a US non-Hispanic white population. Odds ratio (OR) and 95% confidence interval (CI) were calculated in multivariate logistic regression analysis.
We found that the CASP3 rs4647601:TT variant genotype was associated with an increased risk of SCCHN (adjusted OR = 1.32, 95% CI = 1.00–1.73) compared with the GG genotype. This risk was more evident in the subgroups of younger (≤56 years) subjects, males, and never smokers with a significant trend for increased risk with increased number of variant T allele (P < 0.05 for all). However, these risks were not found for other two SNPs. Furthermore, individuals with two copies of haplotypes TCG or GCA were found to have a significant increased risk of SCCHN (OR = 1.31, 95% CI = 1.07–1.61), compared with the others haplotypes, and this risk was more evident in less advanced diseases (OR = 1.45, 95% CI = 1.11–1.89) than in the advanced diseases (OR = 1.22, 95% CI = 0.96–1.54).
These results suggested that genetic variation in CASP3 may contribute to SCCHN risk. Larger studies are needed to confirm our findings.
The establishment of genetic variation in CASP3 as a risk factor for SCCHN risk is an etiologically important step in predicting risk in the general population for further identification of individuals at risk for primary prevention. Indeed, this study found one of the three CASP3 SNPs to be associated with risk of SCCHN, particularly in younger, male, and never smokers with less advanced SCCHN, suggesting this SNP was a marker for susceptibility to but not disease progression of SCCHN.
Case-control study; Apoptosis; Genetic susceptibility; Molecular epidemiology; Polymorphism
Excision repair cross-complementation group 4 gene (ERCC4/XPF) plays an important role in nucleotide excision repair and participates in removal of DNA interstrand cross-links and DNA double-strand breaks. Single nucleotide polymorphisms (SNPs) in ERCC4 may impact repair capacity and affect cancer susceptibility.
In this case-control study, we evaluated associations of four selected potentially functional SNPs in ERCC4 with risk of squamous cell carcinoma of the head and neck (SCCHN) in 1,040 non-Hispanic white patients with SCCHN and 1,046 cancer-free matched controls. We found that the variant GG genotype of rs2276466 was significantly associated with a decreased risk of SCCHN (OR = 0.69, 95% CI 0.50–0.96), and that the variant TT genotype of rs3136038 showed a borderline significant decreased risk with SCCHN (OR = 0.76, 95% CI: 0.58–1.01) in the recessive model. Such protective effects were more evident in oropharyngeal cancer (OR = 0.61, 95% CI: 0.40–0.92 for rs2276466; OR = 0.69, 95% CI: 0.48–0.98 for rs3136038). No significant associations were found for the other two SNPs (rs1800067 and rs1799798). In addition, individuals with the rs2276466 GG or with the rs3136038 TT genotypes had higher levels of ERCC4 mRNA expression than those with the corresponding wild-type genotypes in 90 Epstein-Barr virus-transformed lymphoblastoid cell lines derived from Caucasians.
These results suggest that these two SNPs (rs2276466 and rs3136038) in ERCC4 may be functional and contribute to SCCHN susceptibility. However, our findings need to be replicated in further large epidemiological and functional studies.
Cyclooxygenase-2 (COX-2) is involved in inflammation and carcinogenesis. Interleukin-10 (IL-10) is also regarded as anti-inflammatory factors with the multi-functional ability to positively and negatively influence functional immunity and tumor development. Genetic polymorphisms of COX-2 and IL-10 might contribute to the development of squamous cell carcinoma of the head and neck (SCCHN). The purpose of this study was to evaluate the association of COX-2 and IL-10 single nucleotide polymorphisms (SNPs) with the risk of SCCHN in a Korean sample. We analyzed the COX-2 SNPs, -1329A>G, +1266C>T, and +6365T>C, and the IL-10 SNPs, -1082A>G, +920T>G, and +3917T>C, in 290 Korean SCCHN patients and 358 healthy controls. There was no significant association between the risk of SCCHN and the three COX-2 or three IL-10 SNPs. We analyzed three haplotypes (ht1, ht2, ht3) for COX-2 and found that COX-2 ht3+/+ was associated with a decreased risk of SCCHN in a Korean sample, compared with the COX-2 ht3 -/- genotype (P=0.03). Two haplotypes (ht1, ht2) of IL-10 were analyzed and there was no statistical significance in the distribution of haplotypes. Based on these results, the COX-2 haplotype ht3 can be used as a molecular biomarker to predict low risk groups of SCCHN in a Korean sample.
Carcinom, Squamous Cell; Head and Neck Neoplasms; Cyclooxygenase 2; Interleukin-10; Polymorphism, Genetic; Polymorphism, Single Nucleotide
Although the role of TNFAIP2 is still unclear, it is an important gene involved in apoptosis, and there are single-nucleotide polymorphisms (SNPs) at its microRNA (miRNA)-binding sites that could modulate miRNA target gene function. In this study, we evaluated associations of four selected SNPs (rs8126 T > C, rs710100 G > A, rs1052912 G > A and rs1052823 G > T) in the miRNA-binding sites of the 3′ untranslated region (UTR) with squamous cell carcinoma of the head and neck (SCCHN) risk in 1077 patients with SCCHN and 1073 cancer-free controls in a non-Hispanic White population. We found that, compared with the rs8126 TT genotype, the variant C allele were associated with increased SCCHN risk in an allele dose–response manner (adjusted odds ratio = 1.48 and 95% confidence interval = 1.06–2.05 for CC, respectively; Ptrend = 0.009). No significant associations were seen for the other three SNPs (rs710100 G > A, rs1052912 G > A and rs1052823 G > T). Additionally, we identified that the rs8126 T > C SNP is within the miR-184 seed binding region in the 3′ UTR of TNFAIP2. Further functional analyses showed that the rs8126 variant C allele led to significantly lower luciferase activity, compared with the T allele. In the genotype–phenotype correlation analysis of peripheral blood mononuclear cells from 64 SCCHN patients, the rs8126 CC genotype was associated with reduced expression of TNFAIP2 messenger RNA. Taken together, these findings indicate that the miR-184 binding site SNP (rs8126 T > C) in the 3′ UTR of TNFAIP2 is functional by modulating TNFAIP2 expression and contributes to SCCHN susceptibility. Larger replication studies are needed to confirm our findings.
p53 plays a critical role in cellular anti-cancer mechanisms, and has been correlated with second primary malignancy (SPM) development. A common polymorphism in codon 72 of the p53 results in an amino acid substitution and could influence p53 function. We hypothesized that p53 codon 72 polymorphism may be associated with risk of SPMs and SPM-free survival among patients with squamous cell carcinoma of the head and neck (SCCHN).
A total of 1,271 patients, who were diagnosed with incident SCCHN between May 1995 and January 2007, were genotyped and followed for SPM development. Log-rank test and Cox proportional hazard models were used to compare SPM-free survival and SPM risk between the different genotype groups.
We found a significantly reduced SPM-free survival for patients with variant Pro72 allele compared with patients with Arg 72 homozygous genotype (Log-rank test, p = 0.005). Compared to SCCHN patients with the p53 72Arg/Arg genotype, there was a significantly greater risk of SPM associated with the p53 72Arg/Pro genotype (HR, 1.75, 95% CI, 1.17–2.61) and the combined p53 72Arg/Pro + Pro/Pro (HR, 1.58, 95%CI, 1.07–2.34). Furthermore, stratification analyses showed that the risk of SPM associated with p53 variant genotypes (Arg/Pro + Pro/Pro) was more pronounced in several subgroups.
Our findings suggest that p53 codon 72 polymorphism could be a risk marker for genetic susceptibility to SPM of patients with primary SCCHN.
p53 polymorphism; genetic susceptibility; second primary malignancy; squamous cell carcinoma; head and neck cancer; molecular epidemiology; survival
Deregulated expression of most members of the E2F family has been detected in many human cancers. We examined the association of common single nucleotide polymorphisms (SNPs) of E2F1 and E2F2 with risk of squamous cell carcinoma of the head and neck (SCCHN) in 1,096 SCCHN patients and 1,090 cancer-free controls. We genotyped ten selected SNPs in E2F1 and E2F2, including those at the near 5′ UTR, miRNA binding sites at the near 3′ UTR and tagSNPs according to bioinfotmatics analysis. Although none of the selected SNPs alone was significantly associated with risk of SCCHN, there was a statistically significantly increased risk of SCCHN associated with the combined risk genotypes (i.e. rs3213182 AA, rs3213183 GG, rs3213180 GG, rs321318121 GG, rs2742976 GT+TT, rs6667575 GA+AA, rs3218203 CC, rs3218148 AA, rs3218211 CC, rs3218123 GT+TT). Compared with those with 0–4 risk genotypes, an increased risk was observed for those who carried 5–8 risk genotypes (adjusted OR = 1.04; 95% CI = 0.86–1.26) and 9–10 risk genotypes (adjusted OR = 1.62; 95% CI = 1.14–2.30) in a dose-response manner (P = 0.045). Furthermore, the joint effect was more pronounced among patients with oropharyngeal cancer, younger adults (≤57 years old), men, non-smokers, non-drinkers, and individuals with family history of cancer first-degree relatives. Additionally, we also observed that those with 5–10 risk genotypes had an earlier SCCHN onset than those with 0–4 risk genotypes, particularly for non-smokers and/or non-drinkers. We concluded that E2F1 and E2F2 genetic variants may jointly play important roles in head and neck carcinogenesis.
E2F1; E2F2; head and neck cancer; polymorphisms; age at onset
Recently, several studies have investigated the association between a newly reported rare functional single nucleotide polymorphism (SNP) in TP53 (rs78378222) and cancer risk but generated inconsistent findings. The present study further investigated this association with risk of melanoma, squamous cell carcinoma of head and neck (SCCHN) and lung cancer. Using subjects of non-Hispanic whites recruited for three large case-control studies, we genotyped the TP53 rs78378222 SNP in 1,329 patients with melanoma, 1,096 with SCCHN, 1,013 with lung cancer, and 3000 cancer-free controls. Overall, we did not observe any variant homozygotes in this study population, nor significant associations between the TP53 rs78378222AC genotype or C allele and risk for melanoma (P=0.680 and 0.682, respectively) and lung cancer (P=0.379 and 0.382, respectively) but a protection against SCCHN (P=0.008 and 0.008, respectively), compared with the AA genotype or A allele. An additional meta-analysis including 19,423 cancer patients and 54,050 control subjects did not support such a risk association either. Our studies did not provide statistical evidence of an association between this rare TP53 variant and increased risk of melanoma, nor of lung cancer, but a possible protection against SCCHN.
biomarker; genetic susceptibility; genotype; polymorphism
Recently, several studies have investigated the association between a newly reported rare functional single nucleotide polymorphism (SNP) in TP53 (rs78378222) and cancer risk, but generated inconsistent findings. The present study further investigated this association with risk of melanoma, squamous cell carcinoma of head and neck (SCCHN) and lung cancer. Using volunteers of non-Hispanic Whites recruited for three large case–control studies, we genotyped the TP53 rs78378222 SNP in 1329 patients with melanoma, 1096 with SCCHN, 1013 with lung cancer and 3000 cancer-free controls. Overall, we did not observe any variant homozygotes in this study population, nor significant associations between the TP53 rs78378222AC genotype or C allele and risk for melanoma (P = 0.680 and 0.682 respectively) and lung cancer (P = 0.379 and 0.382 respectively), but a protection against SCCHN (P = 0.008 and 0.008 respectively), compared with the AA genotype or A allele. An additional meta-analysis including 19,423 cancer patients and 54,050 controls did not support such a risk association either. Our studies did not provide statistical evidence of an association between this rare TP53 variant and increased risk of melanoma, nor of lung cancer, but a possible protection against SCCHN.
biomarker; genetic susceptibility; genotype; polymorphism
The purpose of this study is to analyze the combined effects of selected p53 and p73 polymorphisms and their interaction with lifestyle habits on squamous cell carcinoma of the head and neck (SCCHN) risk and progression in an Italian population.
Two hundred and eighty-three cases and 295 hospital controls were genotyped for p53 polymorphisms on exon 4 (Arg72Pro), intron 3 and 6, and p73 G4C14-to-A4T14. Their association with SCCHN was estimated using a logistic regression analysis, while a multinomial logistic regression approach was applied to calculate the effect of the selected polymorphisms on SCCHN different sites (oral cavity, oropharynx, hypopharynx and larynx). We performed an haplotype analysis of the p53 polymorphisms, and a gene-gene interaction analysis for the combined effects of p73 G4C14-to-A4T14 and p53 polymorphisms.
We found a significant increased risk of SCCHN among individuals with combined p73 exon 2 G4A and p53 intron 3 variant alleles (OR = 2.22, 95% CI: 1.08–4.56), and a protective effect for those carrying the p53 exon 4-p53 intron 6 diplotype combination (OR = 0.67; 95% CI: 0.47–0.92). From the gene-environment interaction analysis we found that individuals aged < 45 years carrying p73 exon 2 G4A variant allele have a 12.85-increased risk of SCCHN (95% CI: 2.10–78.74) compared with persons of the same age with the homozygous wild type genotype. Improved survival rate was observed among p53 intron 6 variant allele carriers (Hazard Ratio = 0.51 (95% CI: 0.23–1.16).
Our study provides for the first time evidence that individuals carrying p53 exon 4 and p53 intron 6 variant alleles are significantly protected against SCCHN, and also shows that an additional risk is conferred by the combination of p73 exon 2 G4C14-to-A4T14 and p53 intron 3 variant allele. Larger studies are required to confirm these findings.
Fas-associated phosphatase-1 is encoded by the protein tyrosine phosphatase, non-receptor type 13 (PTPN13) gene and attributes to the resistance to Fas-mediated apoptosis in several tumors, including squamous cell carcinoma of the head and neck (SCCHN). However, no epidemiological studies have investigated the roles of PTPN13 polymorphisms in SCCHN risk. In this hospital-based case–control study of 1069 SCCHN patients and 1102 non-Hispanic white cancer-free controls, we evaluated the associations between three single-nucleotide polymorphisms c.4068 T>G F1356L (rs10033029), c.4566 A>G I1522M (rs2230600) and c.6241 T>G Y2081D (rs989902) located in the coding region of PTPN13 and SCCHN risk. We found that a significantly increased SCCHN risk was associated with the c.4566 I1522M GG genotype [odds ratio (OR), 1.89; 95% confidence interval (CI), 1.27–2.79] and c.6241 Y2081D GT genotype (OR, 1.26; 95% CI, 1.03–1.53) compared with the c.4566 I1522M AA and c.6241 Y2081D TT genotypes, respectively. Further stratified analyses showed that risk associated with the c.4566 I1522M GG genotype was more profound in the subgroups of young (≤57 years), males, never smokers, current drinkers and patients with pharyngeal cancer; that risk associated with c.6241 Y2081D GT genotype persisted in subgroups of old (>57 years), males, current drinkers and patients with pharyngeal and laryngeal cancers and that risk associated with c.6241 Y2081D GG genotype was borderline in patients with laryngeal cancer. In conclusion, polymorphisms in the PTPN13 coding region may be biomarkers for susceptibility to SCCHN in USA populations.
Single nucleotide polymorphisms (SNPs) in the promoter region of the FAS and FASLG may alter the transcriptional activity of these genes. We, therefore, investigated the association between the FAS and FASLG polymorphisms and risk of second primary tumor (SPM) after index squamous cell carcinoma of the head and neck (SCCHN).
We used Log-rank test and Cox proportional hazard models to assess the association of the four SNPs (FAS -1377G>A, FAS -670A>G, FASLG -844C>T and FASLG -124 A>G) with the SPM-free survival and SPM risk among 1,286 incident SCCHN patients.
Compared to patients having the FAS -670 AA or the FASLG -844CC genotypes, the patients having variant genotypes of FAS -670 AG/GG or FASLG -844 CT/TT genotypes had a significantly increased risk of SPM, respectively. A trend for significantly increased SPM risk with increasing number of risk genotypes of the four polymorphisms was observed in a dose-response manner. Moreover, the patients with three or four combined risk genotypes had an appropriately 1.8- or 2.5-fold increased risk for developing SPM compared with patients with zero or one risk genotypes, respectively.
Our results suggest a modestly increased risk of SPM after index SCCHN with FAS -670 A>G and FASLG -844 C>T polymorphisms and an even greater risk of SPM with multiple combined FAS and FASLG risk genotypes.
The FAS and FASLG polymorphisms may serve as a susceptible marker for SCCHN patients at high SPM risk.
FAS/FASLG; Squamous cell carcinoma of head and neck; Second primary malignancy; Genetic susceptibility; Polymorphism
PIN1, a new peptidyl-prolyl cis/trans isomerase, regulates the conformation of Pro-directed phosphorylation sites, revealing a new postphosphorylation regulatory mechanism. PIN1-induced conformational changes potentiate multiple oncogenic signaling pathways, and PIN1 overexpression is reported as a prevalent and specific event in human cancers. In this study, we tested the hypothesis that common polymorphisms in the coding and promoter regions of PIN1 are associated with risk of squamous cell carcinoma of the head and neck (SCCHN). We genotyped three selected PIN1 polymorphisms (−842G>C, −667T>C and Gln33Gln) in a hospital-based case–control study of 1006 patients with SCCHN and 1007 cancer-free control subjects. We found that the −842C variant genotypes were associated with decreased risk for SCCHN [Odds Ratio (OR) = 0.74; 95% confidence interval (CI) = 0.59–0.93 for the CG genotype, OR = 0.82; 95% CI = 0.34–2.01 for the CC genotype and OR = 0.74; 95% CI = 0.59–0.93 for CG+CC genotypes, compared with the GG genotype]. However, no altered risks were observed for −667T>C and Gln33Gln polymorphisms. Further experiments of the reporter gene expression driven by the allelic PIN1 promoter showed that the −842G allele had a higher activity than that driven by the −842C allele, suggesting that the −842C allele was associated with a reduced transcriptional activity, a finding consistent with a reduced risk observed in the case–control analysis. Large prospective studies of diverse ethnic groups and diverse cancer sites are warranted to validate our findings.
Head and neck cancer represents 3.3% of all new malignancies and 2.0% of cancer deaths in the USA, the majority of which are squamous in origin. The overall 5 year survival is 60% and worsens with increasing stage at diagnosis. Thus, novel biomarkers for early detection of squamous cell carcinoma of the head and neck (SCCHN) are needed. MicroRNA-137 (miR-137) plays a role in cell cycle control and seems to undergo promoter methylation in oral squamous cell carcinoma tissue. The main objectives of this study were to ascertain whether miR-137 promoter methylation is detectable in oral rinse samples, assess its association with SCCHN and identify potential risk factors for its occurrence. Oral rinse samples were collected from 99 SCCHN patients with no prior history of cancer and 99 cancer-free controls, frequency matched on gender; tumor tissue for 64 patients was also tested. Methylation of the miR-137 promoter, assessed using methylation-specific polymerase chain reaction, was detected in 21.2% oral rinses from SCCHN patients and 3.0% from controls [odds ratio (OR) = 4.80, 95% confidence interval (CI): 1.23–18.82]. Among cases, promoter methylation of miR-137 was associated with female gender (OR = 5.30, 95% CI: 1.20–23.44) and inversely associated with body mass index (BMI) (OR = 0.88, 95% CI: 0.77–0.99). Promoter methylation of miR-137 appears to be a relatively frequently detected event in oral rinse of SCCHN patients and may have future utility as a biomarker in DNA methylation panels. The observed associations with gender and BMI help to shed light on potential risk factors for an altered methylation state in SCCHN.