DNA repair gene ERCC2 polymorphisms and risk of squamous cell carcinoma of the head and neck.

INTRODUCTION: Genetic aberrations of DNA repair enzymes are known to be common events and to be associated with different cancer entities. Aim of the following study was to analyze the genetic association of single nucleotide polymorphisms (SNP) of the DNA repair genes with the risk of squamous cell carcinoma of the head and neck (HNSCC). MATERIALS AND METHODS: Genetic variants ERCC2 Lys751Gln (rs13181), ERCC2 Asp312Asn (rs1799793), XRCC1 Arg194Trp (rs1799782); XRCC1 Gln399Arg (rs25487), XRCC1 Arg280His (rs25489) and XRCC3 Thr241Met (rs861539) were analyzed in a primary study group comprising 169 patients with histologically confirmed HNSCC and 463 healthy control subjects. Polymorphisms associated with HNSCC were furthermore analyzed in an independent replication study including 125 HNSCC. RESULTS: Only the ERCC2 751 Gln/Gln genotype was associated with HNSCC in the primary study (p=0.033) and in the replication study (p=0.023), resulting in an overall odds ratio of 0.54 (95% confidence interval 0.35-0.92; p=0.006). CONCLUSION: Carriers of the homozygous ERCC2 751 Gln/Gln genotype may be at lower risk for HNSCC.

Single nucleotide polymorphisms in the hypoxia-inducible factor-1 gene and colorectal cancer risk.

With an incidence of about 300 000 new cases colorectal cancer (CRC) is the second leading cause of cancer-related death in Europe and the United States. Environmental and genetic factors influence CRC risk. Hypoxia-inducible factor-1 (HIF-1), a heterodimeric protein composed of two subunits, HIF-1 alpha and HIF-1 beta, plays a critical role in oxygen homeostasis and is involved in angiogenesis and cell proliferation. The gene for the HIF-1 alpha subunit (HIF1A) carries two common missense mutations-P582S (rs11549465) and A588T (rs11549467)-which both have been related to increased trans-activation capacity of HIF1A. In our case-control study we investigated the association between these polymorphisms and CRC risk. We investigated 381 patients with histologically confirmed CRC and 2156 control subjects. HIF1A genotypes were determined by exonuclease (TaqMan) assays. For determination of microvessel density (MVD) tumor sections were stained using a mouse monoclonal antibody recognizing the pan-endothelial marker CD31. In a multivariate logistic regression analysis including age and sex neither the HIF1A 582S allele (Odds ratio: 1.204; 95% confidence interval 0.911-1.592; P = 0.193) nor the 588T allele was significantly associated with CRC (Odds ratio: 0.851; 95% confidence interval 0.444-1.631; P = 0.626). However, in an exploratory analysis, the HIF1A 588T allele was associated with tumor localization (P = 0.016) and tumor size (P = 0.003). MVD was similar in tumors of patients carrying HIF1A 588T allele and patients without this rare allele. We conclude that functional polymorphisms in the HIF1A gene do not modify CRC risk but maybe associated with clinic-pathological features of the disease.

The fibrinogen gamma 10034C>T polymorphism is not associated with Peripheral Arterial Disease.

Conversion of fibrinogen to fibrin plays an essential role in hemostasis and results in stabilization of the fibrin clot. Fibrinogen consists of three pairs of non-identical polypeptide chains, encoded by different genes (fibrinogen alpha [FGA], fibrinogen beta [FGB] and fibrinogen gamma [FGG]). A functional single nucleotide polymorphism (SNP) in the 3' untranslated region of the FGG gene (FGG 10034C>T, rs2066865) has been associated with deep venous thrombosis and myocardial infarction. Aim of the present study was to analyze the role of this polymorphism in peripheral arterial disease (PAD). The study was designed as case-control study including 891 patients with documented PAD and 777 control subjects. FGG genotypes were determined by exonuclease (TaqMan) assays. FGG genotype frequencies were not significantly different between PAD patients (CC: 57.3%, CT: 36.7%, TT: 5.8%) and control subjects (CC: 60.9%, CT: 33.5%, TT 5.6%; p=0.35). In a multivariate logistic regression analysis including age, sex, smoking, diabetes, arterial hypertension and hypercholesterolemia, the FGG 10034 T variant was not significantly associated with the presence of PAD (Odds ratio 1.07, 95% confidence interval 0.84 - 1.37; p = 0.60). The FGG 10034C>T polymorphism was furthermore not associated with age at onset of PAD. We conclude that the thrombophilic FGG 10034 T gene variant does not contribute to the genetic susceptibility to PAD.

Association of hypoxia-inducible factor 1-alpha gene polymorphisms and colorectal cancer prognosis.

BACKGROUND: Hypoxia inducible factor-1 (HIF-1) is the key regulator of cellular responses to hypoxia and plays a central role in tumour growth. Recently, two single nucleotide polymorphisms (SNPs) in the HIF-1 alpha gene, C1772T and G1790A, were shown to cause significantly higher transcriptional activity than did the wild-type. This study aimed to investigate the effect of these SNPs on the prognosis of colorectal cancer (CRC). PATIENTS AND METHODS: DNA from 336 CRC patients was genotyped. Genotypes of each polymorphism were tested for association with disease-free survival (DFS) using univariate and multivariate Cox-regression analysis. RESULTS: Genotype frequencies were: CC 75.6%, CT 18.8% and TT 1.8% for HIF1A1 C1772T and GG 93.2%, GA 2.7% and AA 0% for G1790A. A statistically significant association between DFS and clinicopathological features was observed. However, no association was found between HIF1A1 C1772T (p=0.44; risk ratio of recurrence, RR=1.19, 95% confidence interval, CI=0.77 to 1.83) and G1790A (p=0.89; RR=0.92, 95% CI=0.29 to 2.90) polymorphisms and DFS in univariate and multivariate Cox-regression analysis. CONCLUSION: These results suggest that HIF1A1 C1772T and G1790A polymorphisms are not involved in the progression or metastasis of CRC.