Lack of Association ofEPHX1Genotypes and Haplotypes with Oral Cancer in South Indians

Abstract

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.

Systematic Review and Meta-Analysis of the Relationship between EPHX1 Polymorphisms and the Risk of Head and Neck Cancer

“…Eight articles [ 24 – 29 , 31 – 32 ] included in this meta-analysis described 9 case-control studies, with 1890 cases and 1894 controls, revealing an association between the EPHX1 Tyr113His polymorphism and HNC susceptibility. The main results of this pooled analysis are presented in Table 2 and Fig 2 shows forest plots illustrating the effect of the EPHX1 Tyr113His polymorphism on HNC risk.…”

Quantitative assessment of the influence of EPHX1 gene polymorphisms and cancer risk: a meta-analysis with 94,213 subjects

“…Furthermore, 32 studies not in HWE and 39 with less 100 patients were also deleted. Hence, 45 studies [ 8 - 10 , 23 - 63 ] for Tyr113His polymorphism (20,091 cases and 27,396 controls) and 54 studies [ 8 - 10 , 24 - 26 , 28 , 29 , 32 , 34 - 45 , 47 - 51 , 53 , 55 - 61 , 63 - 81 ] for His139Arg polymorphism (19,437 cases and 27,289 controls) were included eventually. Genotype distributions in the controls of all selected studies are in agreement with HWE.…”

“…The findings from some previous studies suggested that genetic polymorphism in EPHX1 has important roles in the development of cancers [ 55 , 86 - 88 ]. However, others reported no association of EPHX1 polymorphisms with risk of cancers [ 24 , 26 , 34 , 45 ]. This inconsistency may be due to tremendous difference in sample size, diverse ethnic background, sampling bias, publication bias, or inadequate statistical power.…”

Quantitative assessment of the influence of EPHX1 gene polymorphisms and cancer risk: a meta-analysis with 94,213 subjects

“…The findings from some previous studies suggested that genetic polymorphism in EPHX1 has important roles in the development of cancers [55,[86][87][88]. However, others reported no association of EPHX1 polymorphisms with risk of cancers [24,26,34,45]. This inconsistency may be due to tremendous difference in sample size, diverse ethnic background, sampling bias, publication bias, or inadequate statistical power.…”

“…Furthermore, 32 studies not in HWE and 39 with less 100 patients were also deleted. Hence, 45 studies [8][9][10] for Tyr113His polymorphism (20,091 cases and 27,396 controls) and 54 studies [8][9][10][24][25][26]28,29,32,[34][35][36][37][38][39][40][41][42][43][44][45][47][48][49][50][51]53,[55][56][57][58][59][60][61][63][64][65][66][67][68][69][70][71][72][73][74][75][76]…”