title: Microsomal Epoxide Hydrolase Polymorphisms and Haplotypes as Determinants of Hepatitis B Virusand Hepatitis C Virus-related Liver Disease in Indian Population.
abstract: BACKGROUND
  Hepatocellular carcinoma (HCC) is the fifth most common cancer and third leading cause of death worldwide. Main causes of HCC are hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. mEPHX, a xenobiotic metabolizing enzyme, exhibits a dual role of procarcinogen detoxification and activation, hence considered as a cancer risk factor as well as a protective factor. Two known polymorphic forms of mEPHX, exon in exon 3 and 4, are associated with the development of HCC.
  
  
  OBJECTIVE
  To determine the association of genotypes and haplotypes of mEPHX with risk of HCC developments separately in HBV- and HCV-infected carriers and patients with hepatitis.
  
  
  METHODS
  Polymerase chain reactions (PCR) were carried out using primers to amplify exon 3 (113 Tyr→His variant) and exon 4 (139 His→Arg) polymorphic sites. To distinguish the wild and variant forms, PCR amplification products were digested with restriction endonucleases EcoRV and Rsa1 for exons 3 and 4, respectively.
  
  
  RESULTS
  Exon 3 genotypes, Y113H and H113H, shared a protective association with HBV-chronic hepatitis infection (P < 0.001 and P< 0.01, respectively) as well as HBV-HCC development (P < 0.001) among HBV-carrier group, while Y113H acts as a risk factor for HCV-chronic hepatitis development (P < 0.001) as well as for HCC development (P < 0.01) with HCV-carrier group as reference. Both H139R and R139R, exon 4 genotypes, acted as a risk factor for HBV/HCV-chronic hepatitis infection and for HBV/HCV-HCC development (P ranges from < 0.05 to < 0.001) with HBV/HCV carriers as reference. 113His-139His and 113His-139Arg haplotypes shared a significant negative and positive association, respectively, with HBV hepatitis and HBV-HCC risk. 113Tyr-139Arg haplotype acted as a risk for HCV-HCC development.
  
  
  CONCLUSIONS
  Polymorphic and haplotypic variant forms of mEPHX exon 3 and 4 variably determine the susceptibility to develop HCC in HBV- and HCV-carrier subjects.
authors.affiliation: Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh - 160012, India.
authors.forename: Beenish
authors.initials: B
authors.lastname: Rahat
authors.affiliation: Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh - 160012, India.
authors.forename: Manjula
authors.initials: M
authors.lastname: Kiran
authors.affiliation: Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh - 160012, India.
authors.forename: Roli
authors.initials: R
authors.lastname: Saxena
authors.affiliation: Department of Hepatology, Postgraduate Institute of Medical Education and Research, Chandigarh - 160012, India.
authors.forename: Yogesh K
authors.initials: YK
authors.lastname: Chawla
authors.affiliation: Department of Transfusion Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh - 160012, India.
authors.forename: Rati R
authors.initials: RR
authors.lastname: Sharma
authors.affiliation: Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh - 160012, India.
authors.forename: Jyotdeep
authors.initials: J
authors.lastname: Kaur
keywords: AFB1, aflatoxin B1; AFP, alfa-fetoprotein; ALP, alkaline phosphatase; Genotype; HBV, hepatitis B virus; HCC, hepatocellular carcinoma; HCV, hepatitis C virus; haplotype; hepatitis B virus; hepatitis C virus; hepatocellular carcinoma; single nucleotide polymorphism; viral hepatitis