Analysis of associations of NAT2 gene polymorphisms with the risk of lung cancer

Studying polymorphic variants of the NAT2 gene (NAT2*5 and NAT2*7) in Nenets populations of Northern Siberia

Background

N-acetyltransferase 2 plays a crucial role in the metabolism of a wide range of xenobiotics, including many drugs, carcinogens, and other chemicals in the human environment. The article presents for the first time data on the frequency of two important “slow” variants of NAT2 gene (NAT2*5, rs1801280 and NAT2*7, rs1799931), which significantly affect the rate of xenobiotics acetylation, among representatives of indigenous populations of Forest and Tundra Nenets in Northern Siberia. The aim of this study was to identify the frequencies of these variants and compare them with frequencies in other ethnic populations.

Results

NAT2*5 (T341C) genotyping revealed frequencies of 28,0% and 38,6% for Tundra and Forest Nenets, respectively. The frequencies of NAT2*7 (G857A) variant were 9,8% and 8,2% for Tundra and Forest Nenets, respectively. Polymorphic variants frequencies for Nenets are intermediate between those in populations of Europeans and Asians. These results can probably be explained by the presence of both European and Asian components in Nenets gene pools.

Conclusions

The results of this study expand the knowledge of NAT2 polymorphism in world populations. These data may also help assess the genetic predisposition of Nenets to multifactorial diseases associated with polymorphism in the NAT2 gene and, in general, contribute to the development of personalized medicine in reference to native people of Siberia.

Association between NAT2 polymorphisms and acute leukemia risk: A meta-analysis

BACKGROUND

N-acetyl-transferase 2 (NAT2) polymorphisms have been demonstrated to be associated with acute leukemia (AL); however, the results remain controversial. The present meta-analysis was performed to provide more precise results.

METHODS

Pubmed, Embase, Cochrane Library, China National Knowledge Infrastructure, and Wanfang databases were used to identify eligible studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the association between NAT2 polymorphisms and AL risk.

RESULTS

Increased risk was found under both heterozygous (OR 1.24, 95% CI 1.02-1.51) and recessive model (OR 1.28, 95% CI 1.06-1.55) for rs1801280. The slow acetylator phenotype (OR 1.22, 95% CI 1.07-1.40) also increased AL risk. Subgroup analysis demonstrated that rs1801280 increased AL risk under the recessive model (OR 1.14, 95% CI 0.93-1.41) in Caucasian population and the co-dominant (OR 1.77, 95% CI 1.40-2.23), homozygous (OR 3.06, 95% CI 1.88-4.99), dominant (OR 2.22, 95% CI 1.56-3.17), recessive model (OR 2.06, 95% CI 1.35-3.16) in the Mixed populations. Association between rs1799929 and decreased AL risk was found in the co-dominant (OR 0.82, 95% CI 0.70-0.97), homozygous (OR 0.65, 95% CI 0.46-0.93), heterozygous (OR 0.71, 95% CI 0.51-1.00), and the recessive model (OR 0.68, 95% CI 0.49-0.94) in the Caucasian group. As for rs1799931, the same effects were found in the co-dominant (OR 0.68, 95% CI 0.49-0.94) and the dominant model (OR 0.68, 95% CI 0.48-0.97) in the mixed group.

CONCLUSION

rs1801280 and the slow acetylator phenotype are risk factors for AL.

Association Between NAT2 Polymorphisms and Lung Cancer Susceptibility

To further investigate the association between NAT2 polymorphisms and lung cancer susceptibility.In terms of phenotypes, we investigated the acetylator status of NAT2 polymorphisms associated with lung cancer risk. Additionally, in view of genotypes, we mainly analyzed 5 single nucleotide polymorphisms (SNPs) in NAT2 gene, namely C282T, A803G, C481T, G590A, and G857A. Twenty-six eligible studies were included in our meta-analysis by searching PubMed, Embase, and CNKI databases. We used odds ratios (ORs) with corresponding 95% confidence intervals (CIs) to evaluate the susceptibility to lung cancer associated with NAT2 polymorphisms.Overall, based on phenotypes, the pooled ORs showed no significant association between NAT2 polymorphisms and lung cancer susceptibility. In the subgroup analyses by ethnicity and source of control, there was still no significant association. In terms of genotypes, overall, no obvious relationship was observed between NAT2 polymorphisms and lung cancer risk. But increased risk of lung cancer was found in association with NAT2 C282T polymorphism (TT vs. CC + TC: OR = 1.58, 95% CI = 1.11-2.25).Our meta-analysis demonstrates that TT genotype in NAT2 C282T polymorphism may be a risk factor for lung cancer susceptibility. Additionally, the acetylator status of 5 SNPs in NAT2 gene may not be associated with lung cancer risk.

An unlikely role for the NAT2 genotypes and haplotypes in the oral cancer of south Indians

The arylamine N-acetyltransferase 2 (NAT2) enzyme detoxifies a wide spectrum of naturally occurring xenobiotics including carcinogens and drugs. Acetylation catalysed by the NAT2 is an important process in metabolic activation of arylamines to electrophilic intermediates that initiate carcinogenesis. Polymorphism in N-acetyltransferase 2 gene was reported to be associated with the susceptibility of various cancers.

OBJECTIVE

The aim of our study was to determine whether there is any association between the susceptibility to oral cancer amongst the variations of NAT2 genotypes.

DESIGN

This study was carried out in 157 patients with oral cancer. The control group consisted of 132 healthy volunteers. The most common polymorphisms rs1799929, rs1799930 and rs1799931 on the NAT2 gene were screened for the genotypes using TaqMan allelic discrimination.

RESULTS

All the three SNPs were polymorphic with minor allele frequency of 0.339, 0.372 and 0.061 for rs1799929, rs1799930 and rs1799931, respectively. None of the polymorphic site deviated from HWE in controls. There were no significant differences in genotype or allele frequencies of three SNPs between controls and cases with oral cancer. Risk of oral cancer development for the carriers of the individual deduced phenotypes was also not statistically significant. Of the 3 studied polymorphisms, 2 were in strong LD and form one haplotype block. None of the haplotype had shown significant association with the oral cancer.

CONCLUSIONS

Our study concludes that the NAT2 genotypes, phenotypes and haplotypes are not involved in the susceptibility to oral cancer in South Indian subjects.

Genetic polymorphism in N-Acetyltransferase (NAT): Population distribution of NAT1 and NAT2 activity

N-Acetyltransferases (NAT) are key enzymes in the conjugation of certain drugs and other xenobiotics with an arylamine structure. Polymorphisms in NAT2 have long been recognized to modulate toxicity produced by the anti-tubercular drug isoniazid, with molecular epidemiologic studies suggesting a link between acetylator phenotype and increased risk for bladder cancer. Recent evidence indicates that the other major NAT isozyme, NAT1, is also polymorphic. The current analysis characterizes the main polymorphisms in both NAT2 and NAT1 in terms of their effect on enzyme activity and frequency in the population. Multiple NAT2 alleles (NAT2*5, *6, *7, and *14) have substantially decreased acetylation activity and are common in Caucasians and populations of African descent. In these groups, most individuals carry at least one copy of a slow acetylator allele, and less than 10% are homozygous for the wild type (fast acetylator) trait. Incorporation of these data into a Monte Carlo modeling framework led to a population distribution of NAT2 activity that was bimodal and associated with considerable variability in each population assessed. The ratio of the median to the first percentile of NAT2 activity ranged from 7 in Caucasians to 18 in the Chinese population. This variability indicates the need for more quantitative approaches (e.g., physiologically based pharmacokinetic [PBPK] modeling) to assess the full distribution of internal dose and adverse responses to aromatic amines and other NAT2 substrates. Polymorphisms in NAT1 are generally associated with relatively minor effects on acetylation function, with Monte Carlo analysis indicating less interindividual variability than seen in NAT2 analysis.