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

UNLABELLED: 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.

Lack of association of EPHX1 genotypes and haplotypes with oral cancer in South Indians.

As genetic variation is thought to contribute to the etiology of oral cancer, microsomal epoxide hydrolase (EPHX1) was chosen as a candidate gene. This study thus sought to investigate possible genetic associations between the rs1051740, rs2292566, and rs2234922 polymorphisms of EPHX1 and oral cancer. Oral cancer patients (n=157) and healthy control subjects (n=132) were screened for the genotypes using TaqMan allelic discrimination. The associations between genotypes, alleles, and haplotypes of the three mutations and oral cancer were then analyzed using a case-control study. All the three single-nucleotide polymorphisms were polymorphic, with minor allele frequencies of 0.368, 0.249, and 0.232, respectively, for rs1051740, rs2292566, and rs2234922. None of the polymorphic sites deviated from Hardy-Weinberg equilibrium. There were no significant differences in genotype or allele frequencies of three single-nucleotide polymorphisms between controls and cases with oral cancer. Of the three studied polymorphisms, two were in strong linkage disequilibrium and formed one haplotype block. None of the haplotypes showed significant association with oral cancer. EPHX1 gene polymorphisms and haplotypes were not involved in the susceptibility to oral cancer in South Indian subjects.