http://repub.eur.nl/res/aut/16042/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/24476/ 2009-04-30T00:00:00Z The p53 protein and its functional homologue p73 share several functions in modulating cell-cycle control and apoptosis. Based on the functional interaction between p53 and p73 in carcinogenesis, we investigated the combined effect of p73 G4C14-to-A4T14 and p53 gene polymorphisms and their interaction with selected environmental factors, on the risk for gastric cancer in a hospital-based case-control study conducted in Italy. The effect of these polymorphisms on cancer progression was also investigated. One hundred and fifteen gastric cancer cases and 295 hospital controls were genotyped for p73 G4C14-to-A4T14, and p53 exon 4 (Arg72Pro), intron 3 and intron 6 polymorphisms. An increased risk for gastric cancer was found to be associated with the inheritance of the p73 homozygous variant genotype among the gastric cancer intestinal histotype (odds ratio (OR) = 6.75; 95% confidence interval (95% CI) = 1.88-24.24). An effect modification of the p73 variant allele by gender was observed [(OR = 2.82; 95%CI = 1.24-6.40) among females, versus an OR of 0.70 (95%CI = 0.32-1.54) among males; p-value for homogeneity among strata estimates =0.03]. Gene-gene interaction analyses demonstrated that individuals with combined p53 exon 4 and intron 6 variant alleles are borderline significantly protected from gastric cancer (OR = 0.52; 95% CI = 0.26-1.07; p-value for interaction =0.005), which was confirmed by the haplotype analysis. Finally, a poorer survival was observed among carriers of the variant allele of p53 intron 6 if compared with those carrying both wild-type alleles (p-value for log-rank test =0.02). This study shows that the p73 G4C14-to-A4T14 polymorphism may be a risk factor for gastric cancer, as reported from other studies in different tumour sites among Caucasians. Along with the protective effect of p53 exon 4-intron 6 allelic variants, already noted for breast and lung cancer, our results require confirmation from larger studies. http://repub.eur.nl/res/pub/25033/ 2009-01-08T00:00:00Z Authors report the results of four meta-analyses of studies that examined the association between methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms and head and neck cancer (nine studies, 2076 cases and 4834 controls for C677T; four studies, 1439 cases and 3941 controls for A1298C), and lung cancer (ten studies, 5274 cases and 7435 controls for C677T; seven studies, 5098 cases and 6243 controls for A1298C). The summary odds ratio (OR) of head and neck cancer was 0.92 (95% CI: 0.76-1.11) for MTHFR 677 TT and 0.68 (95% CI: 0.37-1.26) for MTHFR 1298 CC. The OR of lung cancer was 1.22 [95% confidence interval (CI): 0.95-1.55] for MTHFR 677 TT and 1.07 (95% CI: 0.83-1.38) for MTHFR 1298 CC. Results from the meta-analysis of three studies on C677T stratified according to dietary folate intake showed an increased risk for individuals with low folate intake (OR = 1.37, 95% CI: 0.92-2.06 for head and neck and OR = 1.28, 95% CI: 0.97-1.68 for lung) versus high folate intake (OR = 0.85, 95% CI: 0.63-1.16 for head and neck, and OR = 0.94, 95% CI: 0.79-1.12 for lung). Despite the lack of formal statistical significance, these findings are consistent with the hypothesis that folate play a role in lung and head/neck carcinogenesis, and show the need to incorporate data on folate intake when interpreting results of MTHFR polymorphisms in relation to cancer risk. http://repub.eur.nl/res/pub/25464/ 2009-01-01T00:00:00Z Alcohol drinkinga thigh doses is a risk factor for head and neck cancer, and exposure to acetaldehyde, the principle metabolite of alcohol, is supposed to account for the increased risk. Individuals homozygous for the *2 variant allele of aldehyde dehydrogenase 2 (ALDH2) are unable tometabolize acetaldehyde, which prevents them from alcohol drinking, whereas *1*2 have 6-fold higher blood acetaldehyde concentration postalcohol consumption with respect to *1*1. Accordingto the concept of Mendelian randomization, because this polymorphism is distributed randomly duringg amete formation, its association with head and neck cancer should be not confounded by smoking. We carried out a meta-analysis of ALDH2 and head and neck cancer searchingfo r relevant studies on Medline and Embase up to January 31, 2008, and investigated the consistency between the expected odds ratio (OR) amongd rinkers from the largest pooled analysis amongne ver smokers and the observed OR from thismeta-analysis by an interaction test. Six studies were selected (945 cases, 2,917 controls). The OR of head and neck cancer among *2*2 was 0.53 [95% confidence interval (95% CI), 0.28-1.00] relative to *1*1 and 1.83 (95% CI, 1.21-2.77) among *1*2. The expected OR for head and neck cancer due to alcohol intake among *1*1 was 1.38 (95% CI, 0.88-2.17) and the observed OR among *1*1 compared with 2*2 from this meta-analysis was 1.88 (95% CI, 1.00-3.57; P for interaction = 0.43). Besides showing the effectiveness of the Mendelian randomization approach, these findings support the theory that alcohol increases head and neck cancer risk through the carcinogenic action of acetaldehyde. Copyright http://repub.eur.nl/res/pub/29177/ 2008-03-01T00:00:00Z Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the metabolism of folate, whose role in gastric carcinogenesis is controversial. The authors performed a meta-analysis and individual data pooled analysis of case-control studies that examined the association between C677T and A1298C polymorphisms (the former being associated with low folate serum levels) and gastric cancer (meta-analyses: 16 studies, 2,727 cases and 4,640 controls for C677T and seven studies, 1,223 cases and 2,015 controls for A1298C; pooled analyses: nine studies, 1,540 cases and 2,577 controls for C677T and five studies, 1,146 cases and 1,549 controls for A1298C). An increased risk was found for MTHFR 677 TT in the meta-analysis (odds ratio (OR) = 1.52, 95% confidence interval (CI): 1.31, 1.77) and pooled analysis (OR = 1.49, 95% CI: 1.14, 1.95). No association resulted for MTHFR 1298 CC (meta-OR = 0.94, 95% CI: 0.65, 1.35; pooled OR = 0.90, 95% CI: 0.69, 1.34). Results from the pooled analysis of four studies on C677T stratified according to folate levels showed an increased risk for individuals with low (OR = 2.05, 95% CI: 1.13, 3.72) versus high (OR = 0.95, 95% CI: 0.54, 1.67) folate levels. Overall, these findings support the hypothesis that folate plays a role in gastric carcinogenesis. http://repub.eur.nl/res/pub/29363/ 2008-01-01T00:00:00Z Purpose: As risk-modifiers of alcohol and tobacco effects, metabolic genes polymorphisms were investigated as susceptibility candidates for squamous cell carcinoma of the head and neck (SCCHN). Methods: A total of 210 cases and 245 hospital controls, age and gender matched, were genotyped for CYP1A1, CYP2E1, GSTM1, GSTT1, EPHX1 exons 3 and 4, and NAT2 polymorphisms. A measurement of the biological interaction among two risk factors was estimated by the attributable proportion (AP) due to interaction and its 95% confidence interval (CI). Results: SCCHN risk was associated with high-levels of alcohol intake [OR = 3.50 (95%CI: 1.93-6.35) and OR = 6.47 (95%CI: 2.92-14.35) for 19-30 g/day and >30 g/day, respectively], cigarette smoking [OR = 3.47 (95%CI: 1.88-6.41) and OR = 7.65 (95%CI: 4.20-13.90) for 1-25 and >25 pack-years of smoking, respectively] and low-fruit and vegetables consumption (OR = 2.45; 95%CI: 1.53-3.92). No differences were observed for the genotypes or haplotypes distributions among cases and controls, and no biological interaction emerged from gene-gene and gene-environment interaction analyses. An attributable proportion (AP) due to biological interaction of 0.65 (95%CI: 0.40-0.90) was detected for heavy drinkers with a low intake of fruit and vegetables, and an AP of 0.40 (95%CI: 0.10-0.72) resulted forever smokers with low fruit and vegetables consumption. Conclusions: Even in presence of high alcohol consumption or cigarette smoking, a high intake of fruit and vegetables might prevent the development of around one quarter of SCCHN cases. The lack of interaction between the studied polymorphisms and the environmental exposures suggests that chronic consumption of tobacco and alcohol overwhelm enzyme defences, irrespective of genotype. http://repub.eur.nl/res/pub/36854/ 2007-11-08T00:00:00Z Background: The distribution and the potential gene-gene and gene-environment interaction of selected metabolic genetic polymorphisms was investigated in relation to gastric cancer risk in an Italian population. Methods: One hundred and seven cases and 254 hospital controls, matched by age and gender, were genotyped for CYP1A1, CYP2E1, mEH, GSTM1, GSTT1, NAT2 and SULT1A1 polymorphisms. Haplotype analysis was performed for EPHX1 exons 3 and 4, as well as CYP2E1 RsaI (*5 alleles) and CYP2E1 DraI (*5A or *6 alleles). The effect modification by alcohol and cigarette smoking was tested with the heterogeneity test, while the attributable proportion (AP) was used to measure the biological interaction from the gene-gene interaction analysis. Results: Gastric cancer risk was found to be associated with the inheritance of GSTT1 null genotype (OR = 2.10, 95%CI: 1.27-3.44) and the SULT1A1 His/His genotype (OR = 2.46, 95%CI: 1.03-5.90). No differences were observed for the haplotype distributions among cases and controls. For the first time an increased risk was detected among individuals carrying the *6 variant allele of CYP2E1 if ever-drinkers (OR = 3.70; 95%CI: 1.45-9.37) with respect to never-drinkers (OR = 0.18; 95% CI: 0.22-1.46) (p value of heterogeneity among the two estimates = 0.001). Similarly, the effect of SULT1A1 variant genotype resulted restricted to ever-smokers, with an OR of 2.58 (95%CI: 1.27-5.25) for the carriers of His allele among smokers, and an OR of 0.86 (95%CI: 0.45-1.64) among never-smokers (p value of heterogeneity among the two estimates = 0.03). The gene-gene interaction analyses demonstrated that individuals with combined GSTT1 null and NAT2 slow acetylators had an additional increased risk of gastric cancer, with an OR of 3.00 (95%CI: 1.52-5.93) and an AP of 52%. Conclusion: GSTT1, SULT1A1 and NAT2 polymorphisms appear to modulate individual's susceptibility to gastric cancer in this Italian population, particularly when more than one unfavourable genotype is present, or when combined with cigarette smoke. The increased risk for the carriers of CYP2E1*5A or *6 alleles among drinkers need to be confirmed by larger prospective studies. http://repub.eur.nl/res/pub/36756/ 2007-11-01T00:00:00Z Methylenetetrahydrofolate reductase (MTHFR) plays a central role in the metabolism of folate, which provides a methyl donor for DNA methylation and deoxynucleoside synthesis. We performed a case-control study to explore the relationship between two common MTHFR polymorphisms (C677T and A1298C), their combination and interaction with environmental exposures, on gastric adenocarcinoma susceptibility and progression in an Italian population. One hundred and two cases and 254 hospital controls, matched by age and gender, were enrolled. Individuals carrying the MTHFR 677T allele showed an increased risk of gastric cancer (odds ratio (OR) 1.62, 95% confidence interval (CI) 0.98-2.67), particularly among ever smokers (OR 2.10, 95% CI 1.07-5.33) and, among 677 TT individuals, those with a low intake of fruit and vegetables (OR 2.18, 95% CI 1.05-4.54). The strongest effect, however, was noted for the MTHFR 677 TT genotype among the diffuse gastric cancer histotype (OR 2.92, 95% CI 1.12-7.60). No association was detected for the effect of MTHFR A1298C polymorphism. Survival analysis did not show any association between each polymorphism on the overall survival, although when the analysis was restricted to the first year of follow-up after the surgical intervention an improved survival was noted among MTHFR 677 CC subjects compared with the T allele carriers (p value for log-rank test 0.02). In conclusion, MTHFR 677 (any T genotype) appears to modulate an individual's susceptibility to gastric cancer, particularly when combined with cigarette smoking and among those with a low intake of fruit and vegetables. Our results also suggest that an aberrant DNA methylation pattern, through impaired folate metabolism, might play a key role in gastric carcinogenesis. A possible survival effect of the MTHFR C677T genotype in gastric cancer patients deserves further investigations with larger sample sizes. http://repub.eur.nl/res/pub/37119/ 2007-05-10T00:00:00Z Scientific literature may be biased because of the internal validity of studies being compromised by different forms of measurement error, and/or because of the selective reporting of positive and 'statistically significant' results. While the first source of bias might be prevented, and in some cases corrected to a degree, the second represents a pervasive problem afflicting the medical literature; a situation that can only be 'corrected' by a change in the mindset of authors, reviewers, and editors. This review focuses on the concepts of confounding, selection bias and information bias, utilising explanatory examples and simple rules to recognise and, when possible, to correct for them. Confounding is a mixing of effects resulting from an imbalance of some of the causes of disease across the compared groups. It can be prevented by randomization and restriction, and controlled by stratification, standardization or by using multivariable techniques. Selection bias stems from an absence of comparability among the groups being studied, while information bias arises from distorted information collection techniques. Publication bias of medical research results can invalidate evidence-based medicine, when a researcher attempting to collect all the published studies on a specific topic actually gathers only a proportion of them, usually the ones reporting 'positive' results. The selective publication of 'statistically significant' results represents a problem that researchers and readers have to be aware of in order to face the entire body of published medical evidence with a degree of scepticism. http://repub.eur.nl/res/pub/14020/ 2007-01-01T00:00:00Z Studies investigating the association between cytochrome P450 2E1 (CYP2E1) 5'-flanking region (PstI/RsaI) polymorphism and gastric cancer risk report conflicting results. The rationale for this meta-analysis was to determine whether CYP2E1*2 (c2) variant allele of CYP2E1 increases gastric cancer risk, especially by interacting with smoking, alcohol and other metabolic gene polymorphisms. Two investigators independently searched the Medline and Embase databases. A qualitative scoring of papers was applied to their evaluation. Authors of the identified papers were contacted to obtain data on the mentioned co-exposures. A measurement of the biological interaction among two putative risk factors was estimated by the attributable proportion (AP) due to interaction. We identified 13 case-control studies, which included 2066 gastric cancer cases and 2754 controls. Using the random effects model, we found no association between PstI/RsaI genotype and gastric cancer risk [odds ratio (OR) = 0.97 (95% confidence interval (CI): 0.79-1.18) for c2 allele carriers and OR = 1.36 (95% CI: 0.82-2.25) for c2 homozygotes compared with homozygotes wild-type]. When only high-quality scored studies were considered, a statistically significant increased risk appeared among Asians [OR = 1.50 (95% CI: 1.16-1.94) for c2 carriers and OR = 2.62 (95% CI: 1.23-5.57) for c2 homozygotes]. No interaction was detected between CYP2E1-smoking/alcohol (AP = 0), while an AP of 60% appeared for individuals both c2 homozygotes and glutathione S-transferase M1 (GSTM1) null compared with both homozygotes wild-type. This meta-analysis suggests that the CYP2E1 PstI/RsaI polymorphism may be a risk factor for gastric cancer in Asians, and that a synergic relation among GSTM1 and CYP2E1 may account for a proportion of gastric cancer cases.