Gene Summary

Gene:NAT2; N-acetyltransferase 2 (arylamine N-acetyltransferase)
Aliases: AAC2, PNAT, NAT-2
Summary:This gene encodes an enzyme that functions to both activate and deactivate arylamine and hydrazine drugs and carcinogens. Polymorphisms in this gene are responsible for the N-acetylation polymorphism in which human populations segregate into rapid, intermediate, and slow acetylator phenotypes. Polymorphisms in this gene are also associated with higher incidences of cancer and drug toxicity. A second arylamine N-acetyltransferase gene (NAT1) is located near this gene (NAT2). [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:arylamine N-acetyltransferase 2
Source:NCBIAccessed: 27 February, 2015


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 27 February 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 27 February, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (7)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: NAT2 (cancer-related)

Yu J, Deng Y, Chen JP
N-acetyltransferase 2 status and gastric cancer risk: a meta-analysis.
Tumour Biol. 2014; 35(7):6861-5 [PubMed] Related Publications
Case-control studies on the association between N-acetyltransferase 2 (NAT2) genotype and gastric cancer have provided either controversial or inconclusive results. In order to clarify the influence of NAT2 acetylation status on gastric cancer risk, a meta-analysis was undertaken. The primary outcome measure was the odds ratio (OR) for the risk of gastric cancer associated with the NAT2 genotype. The overall result showed that there was no statistically significant association between NAT2 status and gastric cancer risk (slow acetylation vs. rapid acetylation, OR = 1.10, 95 % confidence interval (CI) 0.97-1.25, p = 0.12). In the analysis stratified by East Asian ethnicity, a significant association was found between gastric cancer and the NAT2 genotype (slow acetylation vs. rapid acetylation, OR = 1.33, 95 % CI 1.11-1.59, p = 0.002). Our pooled data suggest that the NAT2 acetylation status has an effect on the risk of gastric cancer among East Asian populations.

Marques CR, Da Silva TM, De Albuquerque DM, et al.
NAT2, XRCC1 and hOGG1 polymorphisms, cigarette smoking, alcohol consumption and risk of upper aerodigestive tract cancer.
Anticancer Res. 2014; 34(6):3217-24 [PubMed] Related Publications
AIM: To evaluate associations between polymorphisms of the N-acetyltransferase 2 (NAT2), human 8-oxoguanine glycosylase 1 (hOGG1) and X-ray repair cross-complementing protein 1 (XRCC1) genes and risk of upper aerodigestive tract (UADT) cancer.
PATIENTS AND METHODS: A case-control study involving 117 cases and 224 controls was undertaken. The NAT2 gene polymorphisms were genotyped by automated sequencing and XRCC1 Arg399Gln and hOGG1 Ser326Cys polymorphisms were determined by Polymerase Chain Reaction followed by Restriction Fragment Length Polymorphism (PCR-RFLP) methods.
RESULTS: Slow metabolization phenotype was significantly associated as a risk factor for the development of UADT cancer (p=0.038). Furthermore, haplotype of slow metabolization was also associated with UADT cancer (p=0.014). The hOGG1 Ser326Cys polymorphism (CG or GG vs. CC genotypes) was shown as a protective factor against UADT cancer in moderate smokers (p=0.031). The XRCC1 Arg399Gln polymorphism (GA or AA vs. GG genotypes), in turn, was a protective factor against UADT cancer only among never-drinkers (p=0.048).
CONCLUSION: Interactions involving NAT2, XRCC1 Arg399Gln and hOGG1 Ser326Cys polymorphisms may modulate the risk of UADT cancer in this population.

Figueroa JD, Han SS, Garcia-Closas M, et al.
Genome-wide interaction study of smoking and bladder cancer risk.
Carcinogenesis. 2014; 35(8):1737-44 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
Bladder cancer is a complex disease with known environmental and genetic risk factors. We performed a genome-wide interaction study (GWAS) of smoking and bladder cancer risk based on primary scan data from 3002 cases and 4411 controls from the National Cancer Institute Bladder Cancer GWAS. Alternative methods were used to evaluate both additive and multiplicative interactions between individual single nucleotide polymorphisms (SNPs) and smoking exposure. SNPs with interaction P values < 5 × 10(-) (5) were evaluated further in an independent dataset of 2422 bladder cancer cases and 5751 controls. We identified 10 SNPs that showed association in a consistent manner with the initial dataset and in the combined dataset, providing evidence of interaction with tobacco use. Further, two of these novel SNPs showed strong evidence of association with bladder cancer in tobacco use subgroups that approached genome-wide significance. Specifically, rs1711973 (FOXF2) on 6p25.3 was a susceptibility SNP for never smokers [combined odds ratio (OR) = 1.34, 95% confidence interval (CI) = 1.20-1.50, P value = 5.18 × 10(-) (7)]; and rs12216499 (RSPH3-TAGAP-EZR) on 6q25.3 was a susceptibility SNP for ever smokers (combined OR = 0.75, 95% CI = 0.67-0.84, P value = 6.35 × 10(-) (7)). In our analysis of smoking and bladder cancer, the tests for multiplicative interaction seemed to more commonly identify susceptibility loci with associations in never smokers, whereas the additive interaction analysis identified more loci with associations among smokers-including the known smoking and NAT2 acetylation interaction. Our findings provide additional evidence of gene-environment interactions for tobacco and bladder cancer.

Wang L, Tang W, Chen S, et al.
N-acetyltransferase 2 polymorphisms and risk of esophageal cancer in a Chinese population.
PLoS One. 2014; 9(2):e87783 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
Esophageal cancer was the fifth most commonly diagnosed cancer and the fourth leading cause of cancer-related death in China in 2009. Genetic factors might play an important role in the carcinogenesis of esophageal squamous cell carcinoma (ESCC). We conducted a hospital-based case-control study to evaluate ten NAT2 tagging single nucleotide polymorphisms (SNPs) on the risk of ESCC. Six hundred and twenty-nine ESCC cases and 686 controls were recruited. Their genotypes were determined using the ligation detection reaction method. In the single locus analyses, there was a borderline statistically significant difference in genotype frequencies of NAT2 rs1565684 T>C SNP between the cases and the controls (p = 0.057). The NAT2 rs1565684 CC genotype was associated with a borderline significantly increased risk for ESCC (CC vs. TT: adjusted OR = 1.77, 95% CI = 0.97-3.21, p = 0.063 and CC vs. TT/TC: adjusted OR = 1.68, 95% CI = 0.93-3.04, p = 0.085). The association was evident among older patients and patients who never drunk. After the Bonferroni correction, in all comparison models, NAT2 rs1565684 T>C SNP was not associated with ESCC risk (p>0.05). For the other nine NAT2 SNPs, after Bonferroni correction, in all comparison models, the nine SNPs were also not associated with ESCC risk (p>0.05). Thus, nine NAT2 tagging SNPs were not associated with risk of ESCC. NAT2 rs1565684 T>C SNP might play a slight role in ESCC etiology. Additional, larger studies and tissue-specific biological characterization are required to confirm the current findings.

Khrunin AV, Khokhrin DV, Moisseev AA, et al.
Pharmacogenomic assessment of cisplatin-based chemotherapy outcomes in ovarian cancer.
Pharmacogenomics. 2014; 15(3):329-37 [PubMed] Related Publications
AIM: Cisplatin and its analogs are potent antitumor agents. However, their use is restricted by significant variability in tumor response and toxicity. There is a great need to identify genetic markers to predict the most important adverse events and patient outcomes.
MATERIALS & METHODS: We have evaluated the association between polymorphisms in 106 genes involved mainly in xenobiotic metabolism, DNA repair, the cell cycle and apoptosis, and outcomes in 104 ovarian cancer patients receiving cisplatin-cyclophosphamide chemotherapy. Arrayed primer extension technology was used to genotype 228 SNPs.
RESULTS: Ten SNPs in nine genes were found to be associated with one or more of the assessed clinical end points. SNPs in TPMT and NQO1 were significantly associated with progression-free survival. Polymorphisms in ERCC5, RAD52, MUTYH and LIG3 correlated with the occurrence of severe neutropenia. SNPs in NAT2 and EPHX1 were associated with anemia and nephrotoxicity, respectively. A SNP in ADH1C was correlated with complete tumor response.
CONCLUSION: The results obtained suggest that SNPs in different genes involved in drug metabolism can be important in identifying patients at risk for nonresponse to or toxicity from cisplatin-based treatment.

Selinski S, Blaszkewicz M, Ickstadt K, et al.
Improvements in algorithms for phenotype inference: the NAT2 example.
Curr Drug Metab. 2014; 15(2):233-49 [PubMed] Related Publications
Numerous studies have analyzed the impact of N-acetyltransferase 2 (NAT2) polymorphisms on drug efficacy, side effects as well as cancer risk. Here, we present the state of the art of deriving haplotypes from polymorphisms and discuss the available software. PHASE v2.1 is currently considered a gold standard for NAT2 haplotype assignment. In vitro studies have shown that some slow acetylation genotypes confer reduced protein stability. This has been observed particularly for G191A, T341C and G590A. Substantial ethnic variations of the acetylation status have been described. Probably, upcoming agriculture and the resulting change in diet caused a selection pressure for slow acetylation. In recent years much research has been done to reduce the complexity of NAT2 genotyping. Deriving the haplotype from seven SNPs is still considered a gold standard. However, meanwhile several studies have shown that a two-SNP combination, C282T and T341C, results in a similarly good distinction in Caucasians. However, attempts to further reduce complexity to only one 'tagging SNP' (rs1495741) may lead to wrong predictions where phenotypically slow acetylators were genotyped as intermediate or rapid. Numerous studies have shown that slow NAT2 haplotypes are associated with increased urinary bladder cancer risk and increased risk of anti-tuberculosis drug-induced hepatotoxicity. A drawback of the current practice of solely discriminating slow, intermediate and rapid genotypes for phenotype inference is limited resolution of differences between slow acetylators. Future developments to differentiate between slow and ultra-slow genotypes may further improve individualized drug dosing and epidemiological studies of cancer risk.

Procopciuc LM, Osian G
GSTM1-null genotype as a risk factor for sporadic colorectal cancer in a Romanian population. Association with the NAT2-rapid-acetylator phenotype and exposure to environmental factors.
Cancer Invest. 2014; 32(2):53-62 [PubMed] Related Publications
We evaluated the association between the presence of the GSTM1-null genotype and the combined presence of the GSTM1-null genotype/NAT2 rapid acetylator phenotype and the risk of developing sporadic colorectal cancer (CRC), as well as their interaction with environmental risk factors. One hundred and fifty patients with sporadic CRC and 162 controls were genotyped using PCR-RFLP analysis. For testing and quantification of the simple effect (main effect) and of the gene-gene and gene-environment interaction (modification effect), univariate and multivariate logistic regression was used. In the multiplicative model, from the genetic factors, GSTM1-null and NAT2*6B had a statistically significant influence on the risk for CRC, while from the environmental factors, smoking and diet had similar effects. The combination of GSTM1-null/NAT2 rapid acetylator phenotype/smoking behavior or GSTM1-null/NAT2 rapid acetylator phenotype/diet rich in fried red meat was not found to influence the sporadic CRC risk in Romanians, but the GSTM1-null genotype, NAT2 rapid acetylator phenotype influenced the sporadic CRC risk differently depending on the gender of the patient.

Khlifi R, Chakroun A, Hamza-Chaffai A, Rebai A
Association of CYP1A1 and CYP2D6 gene polymorphisms with head and neck cancer in Tunisian patients.
Mol Biol Rep. 2014; 41(4):2591-600 [PubMed] Related Publications
The purpose of this study was to investigate the relationship between head and neck cancer (HNC) and environmental agents and polymorphisms in CYP1A1, CYP2D6, NAT1 and NAT2 metabolic enzymes genes. To the best of our knowledge, this is the first report on polymorphisms in CYP1A1 6310C>T, CYP2D6 Arg365His, NAT1 52936A>T and NAT2 Arg268Lys (NAT2*12A) genes and susceptibility to HNC in Tunisian population. We study the prevalence of these polymorphisms in 169 patients with HNC and 261 control subjects using polymerase chain reaction based methods in a Tunisian population. We detected an association between HNC and CYP1A1 6310C>T (TT) and CYP2D6 Arg365His (His/His) variant carriers (OR 1.75, P = 0.008 and OR 1.66, P = 0.016, respectively). No association was found between the polymorphisms genotypes of NAT1 52936T>A and NAT2 Arg268Lys and risk of HNC. An association between HNC and CYP1A1 (TT) genotype was found among patients with smoking (P = 0.011) and drinking habit (P = 0.009). The combinations of NAT1 (AT or AA) and NAT2 (AA) at-risk genotypes increased HNC risk (OR 4.23, P = 0.005 and OR 3.60, P = 0.048, respectively). However, the combinations of CYP1A1 (AA) and CYP2D6 (CC) genotypes decreased risk of HNC (OR 0.20; P = 0.006). Genetic polymorphisms in CYP1A1 and CYP2D6 may significantly associate with HNC in the Tunisian population. The results of this study suggest a possible gene-environment interaction for certain carcinogen metabolizing enzymes, but larger studies that fully evaluate the interaction are needed.

Scherr DS
Commentary on "common genetic polymorphisms modify the effect of smoking on absolute risk of bladder cancer." Garcia-Closas M, Rothman N, Figueroa JD, Prokunina-Olsson L, Han SS, Baris D, Jacobs EJ, Malats N, De Vivo I, Albanes D, Purdue MP, Sharma S, Fu YP, Kogevinas M, Wang Z, Tang W, Tardón A, Serra C, Carrato A, García-Closas R, Lloreta J, Johnson A, Schwenn M, Karagas MR, Schned A, Andriole G Jr., Grubb R 3rd, Black A, Gapstur SM, Thun M, Diver WR, Weinstein SJ, Virtamo J, Hunter DJ, Caporaso N, Landi MT, Hutchinson A, Burdett L, Jacobs KB, Yeager M, Fraumeni JF Jr., Chanock SJ, Silverman DT, Chatterjee N, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USA.: Cancer Res 2013;73(7):2211-20 [Epub 2013 Mar 27].
Urol Oncol. 2014; 32(2):213-4 [PubMed] Related Publications
Bladder cancer results from the combined effects of environmental and genetic factors, smoking being the strongest risk factor. Evaluating absolute risks resulting from the joint effects of smoking and genetic factors is critical to assess the public health relevance of genetic information. Analyses included up to 3,942 cases and 5,680 controls of European background in seven studies. We tested for multiplicative and additive interactions between smoking and 12 susceptibility loci, individually and combined as a polygenic risk score (PRS). Thirty-year absolute risks and risk differences by levels of the PRS were estimated for U.S. males aged 50 years. Six of 12 variants showed significant additive gene-environment interactions, most notably NAT2 (P = 7×10(-4)) and UGT1A6 (P = 8×10(-4)). The 30-year absolute risk of bladder cancer in U.S. males was 6.2% for all current smokers. This risk ranged from 2.9% for current smokers in the lowest quartile of the PRS to 9.9% for current smokers in the upper quartile. Risk difference estimates indicated that 8,200 cases would be prevented if elimination of smoking occurred in 100,000 men in the upper PRS quartile compared with 2,000 cases prevented by a similar effort in the lowest PRS quartile (P(additive) = 1×10(-4)). Thus, the potential impact of eliminating smoking on the number of bladder cancer cases prevented is larger for individuals at higher than lower genetic risk. Our findings could have implications for targeted prevention strategies. However, other smoking-related diseases, as well as practical and ethical considerations, need to be considered before any recommendations could be made.

Zhang L, Xiang Z, Hao R, et al.
N-acetyltransferase 2 genetic variants confer the susceptibility to head and neck carcinoma: evidence from 23 case-control studies.
Tumour Biol. 2014; 35(4):3585-95 [PubMed] Related Publications
Previous evidence indicated that N-acetyltransferase 2 (NAT2) polymorphisms might be a risk factor for several cancers. A number of studies have been conducted on the association between NAT2 polymorphisms and head and neck cancer (HNC) risk. Nevertheless, the results were conflicting. Published meta-analysis on this issue has generated inconclusive results. Thus, we aimed to derive a more precise estimation of the relationship by conducting an updated meta-analysis. Published data prior to August 2013 have been searched and screened. Subgroup analysis on ethnicity, source of controls, sample size, and genotyping method were also performed. As a result, a total of 23 case-control studies including 4,028 cases and 4,872 controls were selected for analysis. Interestingly, the results showed that NAT2 polymorphisms might increase HNC risk for the overall data (OR 1.23, 95% CI 1.01-1.49). Moreover, in subgroup analyses according to ethnicity, data showed that slow acetylators might increase HNC susceptibility among Asians (OR 1.78, 95% CI 1.27-2.49), but not among Caucasians or mixed ethnicities. In conclusion, NAT2 polymorphism might be a low-penetrant risk factor for HNC among Asians.

Dik VK, Bueno-de-Mesquita HB, Van Oijen MG, et al.
Coffee and tea consumption, genotype-based CYP1A2 and NAT2 activity and colorectal cancer risk-results from the EPIC cohort study.
Int J Cancer. 2014; 135(2):401-12 [PubMed] Related Publications
Coffee and tea contain numerous antimutagenic and antioxidant components and high levels of caffeine that may protect against colorectal cancer (CRC). We investigated the association between coffee and tea consumption and CRC risk and studied potential effect modification by CYP1A2 and NAT2 genotypes, enzymes involved in the metabolization of caffeine. Data from 477,071 participants (70.2% female) of the European Investigation into Cancer and Nutrition (EPIC) cohort study were analyzed. At baseline (1992-2000) habitual (total, caffeinated and decaffeinated) coffee and tea consumption was assessed with dietary questionnaires. Cox proportional hazards models were used to estimate adjusted hazard ratio's (HR) and 95% confidence intervals (95% CI). Potential effect modification by genotype-based CYP1A2 and NAT2 activity was studied in a nested case-control set of 1,252 cases and 2,175 controls. After a median follow-up of 11.6 years, 4,234 participants developed CRC (mean age 64.7 ± 8.3 years). Total coffee consumption (high vs. non/low) was not associated with CRC risk (HR 1.06, 95% CI 0.95-1.18) or subsite cancers, and no significant associations were found for caffeinated (HR 1.10, 95% CI 0.97-1.26) and decaffeinated coffee (HR 0.96, 95% CI 0.84-1.11) and tea (HR 0.97, 95% CI 0.86-1.09). High coffee and tea consuming subjects with slow CYP1A2 or NAT2 activity had a similar CRC risk compared to non/low coffee and tea consuming subjects with a fast CYP1A2 or NAT2 activity, which suggests that caffeine metabolism does not affect the link between coffee and tea consumption and CRC risk. This study shows that coffee and tea consumption is not likely to be associated with overall CRC.

Khlifi R, Messaoud O, Rebai A, Hamza-Chaffai A
Polymorphisms in the human cytochrome P450 and arylamine N-acetyltransferase: susceptibility to head and neck cancers.
Biomed Res Int. 2013; 2013:582768 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
The occurrence of head and neck cancer (HNC) is associated with smoking and alcohol drinking. Tobacco smoking exposes smokers to a series of carcinogenic chemicals. Cytochrome P450 enzymes (CYP450s), such as CYP1A1, CYP1B1, and CYP2D6, usually metabolize carcinogens to their inactive derivatives, but they occasionally convert the chemicals to more potent carcinogens. In addition, via CYP450 (CYP2E1) oxidase, alcohol is metabolized to acetaldehyde, a highly toxic compound, which plays an important role in carcinogenesis. Furthermore, two N-acetyltransferase isozymes (NATs), NAT1 and NAT2, are polymorphic and catalyze both N-acetylation and O-acetylation of aromatic and heterocyclic amine carcinogens. Genetic polymorphisms are associated with a number of enzymes involved in the metabolism of carcinogens important in the induction of HNC. It has been suggested that such polymorphisms may be linked to cancer susceptibility. In this paper, we select four cytochrome P450 enzymes (CYP1A1, CYP1BA1, CYP2D6, and CYP2E1), and two N-acetyltransferase isozymes (NAT1 and NAT2) in order to summarize and analyze findings from the literature related to HNC risk by focusing on (i) the interaction between these genes and the environment, (ii) the impact of genetic defect on protein activity and/or expression, and (iii) the eventual involvement of race in such associations.

Lee HJ, Wu K, Cox DG, et al.
Polymorphisms in xenobiotic metabolizing genes, intakes of heterocyclic amines and red meat, and postmenopausal breast cancer.
Nutr Cancer. 2013; 65(8):1122-31 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
Heterocyclic amines (HCAs) are mutagenic compounds generated when meats are cooked at high temperature and for long duration. The findings from previous studies on the relation between HCAs and breast cancer are inconsistent, possibly because of genetic variations in the enzymes metabolizing HCAs. To evaluate whether the associations of intakes of estimated HCAs, meat-derived mutagenicity (MDM), and red meat with risk of postmenopausal breast cancer were modified by N-acetyltransferase 2 (NAT2) acetylator genotype or cytochrome P450 1A2-164 A/C (CYP1A2) polymorphism, we conducted a nested case-control study with 579 cases and 981 controls within a prospective cohort, the Nurses' Health Study. HCAs and MDM intakes were derived using a cooking method questionnaire administered in 1996. NAT2acetylator genotype, the CYP1A2 polymorphism, and intakes of HCAs, MDM, and red meat were not associated with risk of postmenopausal breast cancer. There was also no interaction between NAT2 acetylator genotype or CYP1A2 polymorphism and HCAs and MDM and red meat intake in relation to breast cancer. These results do not support the hypothesis that genetic polymorphisms of xenobiotic enzymes involved in the metabolism of HCAs may modify the associations between intakes of red meat or meat-related mutagens and breast cancer risk.

Pesch B, Gawrych K, Rabstein S, et al.
N-acetyltransferase 2 phenotype, occupation, and bladder cancer risk: results from the EPIC cohort.
Cancer Epidemiol Biomarkers Prev. 2013; 22(11):2055-65 [PubMed] Related Publications
BACKGROUND: An association between N-acetyltransferase 2 (NAT2) slow acetylation and bladder cancer has been consistently observed in epidemiologic studies. However, evidence has been mainly derived from case-control studies and was sparse from cohort studies. We evaluated the association between NAT2 slow acetylation and bladder cancer in a case-control study nested in the European Prospective Investigation into Cancer and Nutrition.
METHODS: Exposure to aromatic amines and polycyclic aromatic hydrocarbons (PAH) could be assessed for 754 cases and 833 controls for whom occupational information was documented. A semiquantitative job-exposure matrix was applied to at-risk occupations to estimate the exposure as low, medium, or high based on tertiles of the distribution of the exposure score in controls. Using a comprehensive genotyping, NAT2 acetylation status could be categorized from 6-single-nucleotide polymorphism genotypes as slow or fast in 607 cases and 695 controls with DNA from archived blood samples.
RESULTS: Occupational exposure to aromatic amines and PAH was associated with an increased bladder cancer risk [upper tertile of the distribution of the exposure score: OR = 1.37; 95% confidence interval (CI), 1.02-1.84, and OR = 1.50; 95% CI, 1.09-2.05, respectively]. NAT2 slow acetylation did not modify these risk estimates and was not itself associated with bladder cancer risk (OR = 1.02; 95% CI, 0.81-1.29).
CONCLUSIONS: These findings confirm established or suspected occupational risk factors but not the anticipated role of NAT2 slow acetylation in bladder cancer. No interaction was detected between NAT2 and any exposure of interest, including smoking.
IMPACT: Genetic testing for NAT2 would be inappropriate in occupational settings.

Fernandes MR, de Carvalho DC, dos Santos ÂK, et al.
Association of slow acetylation profile of NAT2 with breast and gastric cancer risk in Brazil.
Anticancer Res. 2013; 33(9):3683-9 [PubMed] Related Publications
BACKGROUND: The N-acetyltransferase 2 (NAT2) gene is a marker for the study of interindividual susceptibility to developing neoplasias. The purpose of this study was to verify a possible association between single nucleotide polymomorphisms (SNPs) of NAT2 and the susceptibility to gastric cancer (GC) and breast cancer (BC) in patients from the North region of Brazil.
MATERIALS AND METHODS: Five SNPs of the NAT2 gene were investigated by direct sequencing. Ancestry was estimated by analysis of a panel with 48 ancestry-informative markers (AIM).
RESULTS: Individuals with slow acetylation profile had an increased risk of developing neoplasias up to three times when compared to controls.
CONCLUSION: In this study, slow acetylation profile was found to strongly influence susceptibility to GC and BC.

Kummar S, Gutierrez ME, Anderson LW, et al.
Pharmacogenetically driven patient selection for a first-in-human phase I trial of batracylin in patients with advanced solid tumors and lymphomas.
Cancer Chemother Pharmacol. 2013; 72(4):917-23 [PubMed] Related Publications
PURPOSE: Batracylin (daniquidone), an ATP-insensitive topoisomerase I/II inhibitor, demonstrated wide interspecies variation in preclinical models consistent with formation of a toxic metabolite, N-acetyl-batracylin, following metabolism by N-acetyl-transferase 2 (NAT2). To minimize exposure to this toxic metabolite, this first-in-human study was conducted in patients with advanced refractory solid tumors or lymphomas demonstrated to have a slow NAT2 acetylator genotype. The objectives were to determine the safety, maximum tolerated dose (MTD), and pharmacokinetics of batracylin and its metabolites.
METHODS: Based on the MTD for rats, the most sensitive species, the starting dose was 5 mg/day for 7 days in 28-day cycles. Dose escalation followed accelerated titration design 4B, with restaging performed every 2 cycles.
RESULTS: Thirty-one patients were enrolled. Treatment was well tolerated; one patient experienced grade 3 toxicity (lymphopenia). Dose escalation was stopped at 400 mg/day due to grade 1 and 2 hemorrhagic cystitis. No objective responses were observed, but prolonged disease stabilization was observed in 2 patients, one with peritoneal mesothelioma (8 cycles) and another with adrenocortical cancer (18 cycles). Across an 80-fold range of doses, the ratios of systemic exposures for batracylin and N-acetyl batracylin were near 1.
CONCLUSIONS: Pharmacogenetically selected patients reached a dose that was 20-fold higher than the MTD in rats and 70 % of the MTD in mice. This genotype-guided strategy was successful in safely delivering batracylin to patients. However, due to unexpected cystitis, not preventable by hydration, and in the absence of a stronger signal for antitumor activity, further development of batracylin has been stopped.

Ferrís J, Garcia J, Berbel O, Ortega JA
Constitutional and occupational risk factors associated with bladder cancer.
Actas Urol Esp. 2013; 37(8):513-22 [PubMed] Related Publications
OBJECTIVE: Bladder carcinoma (BC) is the fourth most common type of cancer in males from Western countries, with primary prevention an important healthcare challenge. We review the associated constitutional and occupational risk factors (RF), with greater or lesser scientific evidence, in the aetiology of BC.
MATERIAL AND METHODS: Literature review of the last 25 years of the constitutional and occupational RF associated with BC, conducted on MedLine, CancerLit, Science Citation Index and Embase. The search profiles were Risk factors/Genetic factors/Genetic polymorphisms/Epidemiology/Occupational factors and Bladder cancer.
RESULTS: The main RF were a) age and gender (diagnosed at age 65 and over, with a 4:1 ratio of males to females); b) race, ethnicity and geographic location (predominantly in Caucasians and in Southern European countries); c) genetic (N-acetyltransferase-2 and glutathione s-transferase M1 gene mutations, which significantly increase the risk for BC); d) occupational, which represent 5%-10% of BC RF; and f) occupations with high BC risk, such as aluminium production, the manufacture of dyes, paints and colourings, the rubber industry and the extraction and industrial use of fossil fuels.
CONCLUSIONS: BC is the end result of the variable combination of constitutional and environmental RF, the majority of which are unknown. The most significant constitutional RF are related to age, gender, race, ethnicity geographic location and genetic polymorphisms. The main occupational RF are those related to aromatic amines and polycyclic aromatic hydrocarbons.

Zgheib NK, Shamseddine AA, Geryess E, et al.
Genetic polymorphisms of CYP2E1, GST, and NAT2 enzymes are not associated with risk of breast cancer in a sample of Lebanese women.
Mutat Res. 2013 Jul-Aug; 747-748:40-7 [PubMed] Related Publications
Changes in the activity of drug metabolizing enzymes (DMEs) are potentially associated with cancer risk. This relationship is attributed to their involvement in the bioactivation of multiple procarcinogens or the metabolism of multiple substrates including an array of xenobiotics and environmental carcinogens. 326 Lebanese women of whom 99 were cancer free (controls) and 227 were diagnosed with breast cancer (cases) were included. Blood for DNA was collected and medical charts were reviewed. Three genotyping methods were employed including: (1) restriction fragment length polymorphism (RFLP) for CYP2E1*5B, CYP2E1*6, NAT2*5 and NAT2*6; (2) gel electrophoresis for GSTM1 and GSTT1; and (3) real-time PCR for GSTP1 Ile/Val polymorphism. We analyzed the relationship between genetic susceptibilities in selected xenobiotic metabolizing genes and breast cancer risk. Allele frequencies were fairly similar to previously reported values from neighboring populations with relevant migration routes. There were no statistically significant differences in the distribution of variant carcinogen metabolizing genes between cases and controls even after adjusting for age at diagnosis, menopausal status, smoking, and alcohol intake. Despite its limitations, this is the first study that assesses the role of genetic polymorphisms in DMEs with breast cancer in a sample of Lebanese women. Further studies are needed to determine the genetic predisposition and gene-environment interactions of breast cancer in this population.

Garcia-Closas M, Rothman N, Figueroa JD, et al.
Common genetic polymorphisms modify the effect of smoking on absolute risk of bladder cancer.
Cancer Res. 2013; 73(7):2211-20 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
Bladder cancer results from the combined effects of environmental and genetic factors, smoking being the strongest risk factor. Evaluating absolute risks resulting from the joint effects of smoking and genetic factors is critical to assess the public health relevance of genetic information. Analyses included up to 3,942 cases and 5,680 controls of European background in seven studies. We tested for multiplicative and additive interactions between smoking and 12 susceptibility loci, individually and combined as a polygenic risk score (PRS). Thirty-year absolute risks and risk differences by levels of the PRS were estimated for U.S. males aged 50 years. Six of 12 variants showed significant additive gene-environment interactions, most notably NAT2 (P = 7 × 10(-4)) and UGT1A6 (P = 8 × 10(-4)). The 30-year absolute risk of bladder cancer in U.S. males was 6.2% for all current smokers. This risk ranged from 2.9% for current smokers in the lowest quartile of the PRS to 9.9% for current smokers in the upper quartile. Risk difference estimates indicated that 8,200 cases would be prevented if elimination of smoking occurred in 100,000 men in the upper PRS quartile compared with 2,000 cases prevented by a similar effort in the lowest PRS quartile (P(additive) = 1 × 10(-4)). Thus, the potential impact of eliminating smoking on the number of bladder cancer cases prevented is larger for individuals at higher than lower genetic risk. Our findings could have implications for targeted prevention strategies. However, other smoking-related diseases, as well as practical and ethical considerations, need to be considered before any recommendations could be made.

Troy JD, Weissfeld JL, Diergaarde B, et al.
Polymorphisms in NAT2 and GSTP1 are associated with survival in oral and oropharyngeal cancer.
Cancer Epidemiol. 2013; 37(4):505-11 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
INTRODUCTION: Functional polymorphisms in drug metabolizing enzymes (DMEs) may be determinants of survival in oral and oropharyngeal squamous cell carcinoma (OOSCC).
METHODS: OOSCC cases (N=159) with a history of either tobacco or alcohol use were genotyped for polymorphisms in eight DMEs. Overall and disease-specific survival were analyzed using Kaplan-Meier plots and the log-rank test. Cox proportional hazards regression was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) in exploratory analyses of patient subgroups.
RESULTS: Kaplan-Meier analyses showed N-acteyltransferase-2 (NAT2) fast acetylators experienced a 19.7% higher 5-year survival rate than slow acetylators (P=0.03) and this association was similar in oropharyngeal and oral cancer. After multiple adjustment, including tumor site and stage, the NAT2 fast acetylator phenotype was associated with improved overall survival (vs. slow acetylators) provided chemotherapy or radiation were not used (HR, 0.26; 95% CI, 0.10-0.66). However, NAT2 phenotype was unrelated to survival in patients treated with chemoradiotherapy (HR, 1.21; 95% CI, 0.54-2.73) or radiotherapy (HR, 0.67; 95% CI, 0.31-1.59) (P-for-NAT2/treatment-interaction=0.04). Normal activity GSTP1 was associated with a 19.2% reduction in 5-year disease-specific survival relative to reduced activity GSTP1 (P=0.04) but this association was not modified by treatment.
CONCLUSIONS: Our results suggest that functional polymorphisms in NAT2 and GSTP1 are associated with OOSCC survival. Confirmation of these results in larger studies is required.

Bonaventure A, Rudant J, Goujon-Bellec S, et al.
Childhood acute leukemia, maternal beverage intake during pregnancy, and metabolic polymorphisms.
Cancer Causes Control. 2013; 24(4):783-93 [PubMed] Related Publications
PURPOSE: This study aimed to analyze the associations between childhood acute leukemia (AL) and maternal caffeinated beverage consumption during pregnancy, and to explore interactions between caffeinated and alcoholic beverage consumption and polymorphisms of enzymes involved in caffeine and ethanol metabolisms.
METHODS: The data were generated by the French ESCALE study, which included 764 AL cases and 1,681 controls in 2003-2004. The case and control mothers were interviewed on their consumption habits during pregnancy using a standardized questionnaire. Genotypes of the candidate alleles (NAT2*5 rs1801280, ADH1C*2 rs698 and rs1693482, CYP2E1*5 rs2031920 and rs3813867) were obtained using high-throughput genotyping and imputation data for 493 AL cases and 549 controls with at least two grandparents born in Europe.
RESULTS: Maternal regular coffee consumption during pregnancy was associated with childhood AL (OR = 1.2 [1.0-1.5], p = 0.02); the odds ratios increased linearly with daily intake (p for trend <0.001; >2 cups per day vs. no or less than 1 cup per week: AL: OR = 1.6 [1.2-2.1], lymphoblastic AL: OR = 1.5 [1.1-2.0], myeloblastic AL: OR = 2.4 [1.3-4.3]). The association was slightly more marked for children born to non-smoking mothers. Lymphoblastic AL was also associated with cola soda drinking (OR = 1.3 [1.0-1.5], p = 0.02). No significant gene-environment interactions with coffee, tea, cola soda, or alcohol drinking were observed.
CONCLUSION: This study provides additional evidence that maternal coffee consumption during pregnancy may be associated with childhood AL. Coffee consumption is a prevalent habit and its potential involvement in childhood AL needs to be considered further.

Barbieri RB, Bufalo NE, Cunha LL, et al.
Genes of detoxification are important modulators of hereditary medullary thyroid carcinoma risk.
Clin Endocrinol (Oxf). 2013; 79(2):288-93 [PubMed] Related Publications
CONTEXT: Different inherited profiles of genes involved in cellular mechanisms of activation and detoxification of carcinogenic products can provide specific protection or determine the risk for cancer. Low-penetrance polymorphic genes related to the biotransformation of environmental toxins have been associated with susceptibility to and the phenotype of, human tumours.
OBJECTIVE: To investigate the role of germline inheritance of polymorphisms in CYP1A2*F, CYP1A1 m1, GSTP1, NAT2 and TP53 genes in hereditary medullary thyroid carcinoma (HMTC) patients.
DESIGN: This study was developed in University of Campinas (Unicamp).
PATIENTS: We studied 132 patients with HMTC, 88 first-degree relatives of HMTC patients and 575 control individuals.
MEASUREMENTS: All patients with MTC and their relatives were sequenced for the RET gene and five genes were genotyped using TaqMan(®) system.
RESULTS: We observed that the inheritance of CYP1A2*F (OR = 2·10; 95% CI = 1·11-3·97; P = 0·022), GSTP1 (OR = 4·41; 95% CI = 2·47-7·88; P < 0·001) and NAT2 (OR = 2·54; 95% CI = 1·16-5·58; P = 0·020) variants increased the risk for HMTC. In addition, multiple regression analysis showed that the inheritance of GSTP1 polymorphisms was associated with the diagnosis in older patients (B = 8·0229; 95% IC = ± 5·5735; P = 0·0054). Concerning the group of HTMC relatives, CYP1A2*F (OR = 2:40; 95% CI = 1·19-4·86; P = 0·015), CYP1A1 m1 (OR = 2·79; 95% CI = 1:04-7·51; P = 0·042), GSTP1 (OR = 2·86; 95% IC = 1·53-5·32; P < 0·001) and NAT2 (OR = 2·25; 95% IC = 1·20-4·22; P = 0·012) were associated with HMTC risk.
CONCLUSIONS: We have demonstrated that the inheritance of specific genes determining the individual response to environmental toxins may contribute to the risk and phenotypic variability that exists in patients with HMTC. Moreover, we identified a group at risk in relatives of HMTC patients.

Selinski S, Blaszkewicz M, Agundez JA, et al.
Clarifying haplotype ambiguity of NAT2 in multi-national cohorts.
Front Biosci (Schol Ed). 2013; 5:672-84 [PubMed] Related Publications
N-Acetyltransferase 2 (NAT2) is the key enzyme in aromatic amine metabolism. NAT2 genotyping requires a subsequent determination of the haplotype pairs (formerly: alleles) to derive the acetylation status. The chromosomal phase of the single nucleotide polymorphisms (SNPs) is unclear for about 2/3 of the genotypes. We investigated NAT2 genotypes of 1,234 bladder cancer cases and 2,207 controls from Germany, Hungary, Pakistan and Venezuela plus 696 further German cancer cases. We reconstructed NAT2 haplotypes using PHASE v2.1.1. We analysed if the variability of the NAT2 haplotypes affected the haplotype reconstruction. Furthermore, we compared population haplotype frequencies in three Caucasian control cohorts (German, Hungarian, Spanish), in Pakistanis and Venezuelans and the impact on bladder cancer. We conclude that a common haplotype reconstruction is feasible, enhances precision and reliability. Hungarian controls showed the largest intra-ethnic variability whereas the Pakistanis showed a haplotype distribution typical for Caucasians. The main differences could be observed for the slow haplotypes *5B, *6A and *7B. The association of slow NAT2 genotypes with bladder cancer risk was most prominent in the Venezuelan study group.

Ma RL, Min L, Chen D, et al.
N-acetyltransferase 2 phenotype and risk of esophageal cancer: a meta analysis.
Cancer Biomark. 2013; 13(6):447-55 [PubMed] Related Publications
N-acetyltransferase 2 (NAT2) gene encodes a phase II enzyme taking part in detoxification of aromatic amines. Published studies have demonstrated that N-Acetyltransferase 2 (NAT2) phenotype is a risk factor of various cancers. Many studies have investigated the association between NAT2 phenotype and susceptibility to esophageal cancer but yielded controversial results. To derive a more precise estimation of this association, a meta-analysis was performed. Electronic databases (Pubmed/Medline, ISI Web of Science and China National Knowledge Infrastructure) in English and Chinese were searched. A total of 5 articles including 476 cases and 1,093 controls were included in this meta-analysis. Odds ratio (OR) with 95% confidence interval (95% CI) was used to evaluate intensity of associations. Pooling studies together, NAT2 slow acetylator phenotype was a significant risk factor of esophageal squamous cell cancer (OR=1.35, 95% CI=1.03-1.77, n=5 studies) but not esophageal adenocarcinoma (OR=0.97, 95% CI=0.47-2.04, n=2 studies). There was a significant association between NAT2 acetylator phenotypes and ESCC in South Asian populations (OR=1.51, 95% CI=1.03-2.20), but not in East Asian populations (OR=1.19, 95% CI=0.80-1.77). Significant association between NAT2 acetylator phenotypes and esophageal cancer was found in population-based control subgroup (OR=1.63, 95% CI=1.07-2.50) but not in hospital-based control subgroup (OR=1.19, 95% CI=0.84-1.69). There is a significant association between NAT2 acetylator phenotype and esophageal cancer in both smokers (OR=1.681, 95% CI=1.179-2.395) and non-smokers (OR=1.614, 95% CI=1.173-2.222). In conclusion, NAT2 slow acetylator phenotype was a significant risk factor of ESCC in Asian populations.

Andersen V, Holst R, Vogel U
Systematic review: diet-gene interactions and the risk of colorectal cancer.
Aliment Pharmacol Ther. 2013; 37(4):383-91 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
BACKGROUND: Diet contributes significantly to colorectal cancer (CRC) aetiology and may be potentially modifiable.
AIM: To review diet-gene interactions, aiming to further the understanding of the underlying biological pathways in CRC development.
METHODS: The PubMed and Medline were systematically searched for prospective studies in relation to diet, colorectal cancer and genetics.
RESULTS: In a meta-analysis, no interaction between NAT1 phenotypes and meat intake in relation to risk of CRC was found (P-value for interaction 0.95). We found a trend towards interaction between NAT2 phenotypes and meat intake in relation to risk of CRC. High meat intake was not associated with risk of CRC among carriers of the slow NAT2 phenotype, whereas NAT2 fast acetylators with high meat intake were at increased risk of CRC (OR = 1.25; 95% confidence interval (CI): 0.92-2.01) compared with slow acetylators with low meat intake (reference), P-value for interaction = 0.07. Low meat intake in the studied populations may influence the result. Interactions between meat, cruciferous vegetables, fibres, calcium, vitamins, and alcohol and ABCB1, NFKB1, GSTM1, GSTT1, CCND1, VDR, MGTM, IL10 and PPARG are suggested.
CONCLUSIONS: A number of interactions between genetic variation and diet are suggested, but the findings need replication in independent, prospective, and well-characterised cohorts before conclusions regarding the underlying biological mechanisms can be reached. When the above criteria are met, studies on diet-gene interactions may contribute valuable insight into the biological mechanisms underlying the role of various dietary items in colorectal carcinogenesis.

Reynolds P
Smoking and breast cancer.
J Mammary Gland Biol Neoplasia. 2013; 18(1):15-23 [PubMed] Related Publications
The potential role of smoking in breast cancer risk has been the subject of over 100 publications, numerous scientific reviews, and animated debate. Tobacco exposure is a well-established cause of lung cancer, and is thought to account for nearly one third of all cancer deaths. Tobacco smoke contains thousands of chemicals, many of which are known to be mammary carcinogens. Although not initially thought to be a tobacco-related cancer, over the last several decades evidence has been accumulating on the role of both active smoking and secondhand smoking in the etiology of breast cancer. The human health evidence has been systematically evaluated not only by several independent researchers but also by several expert agency panels including those of the U.S. Surgeon General, the International Agency for Research on Cancer, the California Environmental Protection Agency, and a coalition of Canadian health agencies. Although the assessments have varied with time and across reviewers, the most recent weight of the evidence has suggested a potentially casual role for active smoking and breast cancer, particularly for long-term heavy smoking and smoking initiation at an early age. The role of secondhand smoking and breast cancer is less clear, although there has been some suggestion for an increased risk for premenopausal breast cancer. Recent studies evaluating the possible modifying role of polymorphisms in genes involved in the metabolism of tobacco products, particularly NAT2, have contributed another dimension to these assessments, although to date that evidence remains equivocal.

Majumder M, Ghosh S, Roy B
Association between polymorphisms at N-acetyltransferase 1 (NAT1) & risk of oral leukoplakia & cancer.
Indian J Med Res. 2012; 136(4):605-13 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
BACKGROUND & OBJECTIVES: N-acetyltransferases 1 and 2 (NAT1 and NAT2) are important enzymes for metabolism of tobacco carcinogens. Due to polymorphisms, improper activities of these enzymes might lead to the formation of DNA adducts that may modulate risk of tobacco related oral precancer and cancer. Previously, it was shown that NAT2 polymorphisms did not modulate the risk of oral precancer and cancer. We undertook this study to check whether polymorphisms at NAT1 can modulate the risk of oral leukoplakia and cancer either alone or in combination with NAT2.
METHODS: Genotypes at four SNPs on NAT1 were determined by TaqMan method in 389 controls, 224 leukoplakia and 310 cancer patients. Genotype data were analyzed to know haplotypes and acetylation status of individuals and, then to estimate the risk of diseases. Using our previously published NAT2 data, combination of NAT1 and NAT2 acetylation genotypes of patients and controls were also analyzed to estimate the risk of diseases.
RESULTS: Analysis of NAT1 genotype data revealed that 1088T and 1095C alleles exist in strong linkage disequilibrium (r 2 =0.97, P<0.0001) and SNPs are in Hardy-Weinberg Equilibrium (P=0.1). Wild type or normal acetylating and variant or rapid acetylating alleles were two major alleles (frequencies 0.62 and 0.36, respectively) present in the control population. NAT1 rapid acetylation could not modulate the risk of leukoplakia and cancer (OR=0.9, 95% CI: 0.6-1.3; OR=1.0, 95% CI: 0.7-1.4, respectively). Analysis of combined NAT1 and NAT2 acetylating data also showed no significant enhancement of the risk of diseases.
INTERPRETATION & CONCLUSIONS: NAT1 rapid acetylation alone as well as combination of NAT1 rapid-NAT2 slow acetylation did not modulate the risk of oral precancer and cancer in our patient population. So, NAT1/NAT2 metabolized carcinogen products may not be involved in tobacco related oral precancer and cancer. It may be interpreted that large sample size as well as combination of polymorphisms at other candidate loci may be important to estimate the risk of a complex disease like oral cancer.

Gibson TM, Smedby KE, Skibola CF, et al.
Smoking, variation in N-acetyltransferase 1 (NAT1) and 2 (NAT2), and risk of non-Hodgkin lymphoma: a pooled analysis within the InterLymph consortium.
Cancer Causes Control. 2013; 24(1):125-34 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
PURPOSE: Studies of smoking and risk of non-Hodgkin lymphoma (NHL) have yielded inconsistent results, possibly due to subtype heterogeneity and/or genetic variation impacting the metabolism of tobacco-derived carcinogens, including substrates of the N-acetyltransferase enzymes NAT1 and NAT2.
METHODS: We conducted a pooled analysis of 5,026 NHL cases and 4,630 controls from seven case-control studies in the international lymphoma epidemiology consortium to examine associations between smoking, variation in the N-acetyltransferase genes NAT1 and NAT2, and risk of NHL subtypes. Smoking data were harmonized across studies, and genetic variants in NAT1 and NAT2 were used to infer acetylation phenotype of the NAT1 and NAT2 enzymes, respectively. Pooled odds ratios (ORs) and 95 % confidence intervals (95 % CIs) for risk of NHL and subtypes were calculated using joint fixed effects unconditional logistic regression models.
RESULTS: Current smoking was associated with a significant 30 % increased risk of follicular lymphoma (n = 1,176) but not NHL overall or other NHL subtypes. The association was similar among NAT2 slow (OR 1.36; 95 % CI 1.07-1.75) and intermediate/rapid (OR 1.27; 95 % CI 0.95-1.69) acetylators (p (interaction) = 0.82) and also did not differ by NAT1*10 allelotype. Neither NAT2 phenotype nor NAT1*10 allelotype was associated with risk of NHL overall or NHL subtypes.
CONCLUSION: The current findings provide further evidence for a modest association between current smoking and follicular lymphoma risk and suggest that this association may not be influenced by variation in the N-acetyltransferase enzymes.

Satagopan JM, Elston RC
Evaluation of removable statistical interaction for binary traits.
Stat Med. 2013; 32(7):1164-90 [PubMed] Article available free on PMC after 01/08/2015 Related Publications
This paper is concerned with evaluating whether an interaction between two sets of risk factors for a binary trait is removable and, when it is removable, fitting a parsimonious additive model using a suitable link function to estimate the disease odds (on the natural logarithm scale). Statisticians define the term 'interaction' as a departure from additivity in a linear model on a specific scale on which the data are measured. Certain interactions may be eliminated via a transformation of the outcome such that the relationship between the risk factors and the outcome is additive on the transformed scale. Such interactions are known as removable interactions. We develop a novel test statistic for detecting the presence of a removable interaction in case-control studies. We consider the Guerrero and Johnson family of transformations and show that this family constitutes an appropriate link function for fitting an additive model when an interaction is removable. We use simulation studies to examine the type I error and power of the proposed test and to show that, when an interaction is removable, an additive model based on the Guerrero and Johnson link function leads to more precise estimates of the disease odds parameters and a better fit. We illustrate the proposed test and use of the transformation by using case-control data from three published studies. Finally, we indicate how one can check that, after transformation, no further interaction is significant.

Roth E, Selinski S, Schikowsky C, et al.
Bladder cancer survival in a former industrial area in Saxony-Anhalt, Germany.
J Toxicol Environ Health A. 2012; 75(19-20):1216-25 [PubMed] Related Publications
Long-term follow-ups on bladder cancer patients from highly industrialized areas are rare. Therefore, we present a follow-up of bladder cancer patients from the greater area Lutherstadt Wittenberg, a center of the chemical industry of the former German Democratic Republic. Relapse-free survival times of 213 confirmed bladder cancer cases from the greater area Lutherstadt Wittenberg were collected between 2008 and 2009. Data on lifestyle and occupational exposure to potential carcinogens was recorded by questionnaire. Genotypes of N-acetyltransferase 2 (NAT2), glutathione S-transferase M1 (GSTM1), glutathione S-transferase T1 (GSTT1), rs710521, and rs9642880 were determined by standard methods. Cox models were used to evaluate differences in relapse-free survival. Clear differences in relapse-free survival could be observed for the number of relapses, multilocular tumor growth, and relapses with higher staging or grading than the primary tumor, as well as GSTT1. None of the other investigated polymorphisms showed significant impact on prognosis. This is the first study on two recently detected single-nucleotide polymorphisms (SNPs) showing that these polymorphisms may also contribute to shorter relapse-free times.

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