Uzay Gormus

Polymorphisms in the microsomal epoxide hydrolase gene: role in lung cancer susceptibility and prognosis

AIMS AND BACKGROUNDnThe aim of this study was to investigate the relationship between EPHXI exon 3 Tyr113His and exon 4 His139Arg polymorphisms, predicted microsomal epoxide hydrolase (mEH) activity, and lung cancer development. mEH is a protective enzyme involved in oxidative defences against a number of environmental chemicals and pollutants, but it is also responsible for the xenobiotic activation of carcinogens.nnnMETHODSnWe investigated the two polymorphisms of the mEH gene (EPHX1) in 58 lung cancer patients and 41 controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).nnnRESULTSnThe exon 3 Tyr113His polymorphism was associated with lung cancer (P < 0.001). The frequency of the His113His homozygote genotype in exon 3 was significantly increased in patients compared with controls (P < 0.001). In contrast, there was no significant difference in exon 4 polymorphisms between patients and controls. When the exon 3 and 4 polymorphisms were considered together, the combined EPHX1 His113His113/His139His139 genotype (very low predicted enzyme activity) was found to be associated with an increased risk of lung cancer (P = 0.044, OR = 3.063, CI = 0.932-10.069). We observed that patients with T3 + T4 tumors had an approximately 3-fold higher risk of the Tyr113/His113 genotype than patients with T1 + T2 tumors. Lung cancer patients carrying a heterozygote Tyr113/His 113 genotype had a 2-fold increased risk of lymph node metastases (P = 0.051).nnnCONCLUSIONnThese findings suggest that the exon 3 Tyr113His and exon 4 His139Arg polymorphisms of EPHXI may be associated with a increased risk of lung cancer and a worse prognosis.

The relationship of oral disturbances of diabetes mellitus patients with paraoxonase gene polymorphisms.

Diabetes Mellitus (DM) is a multisystemic disorder with serious complications and these patients may also have serious problems with their oral cavity probably because of the microangiopathic and neuropathic complications. In diabetic patients, there may be several problems of the oral cavity such as gingivitis, periodontitis, candidiasis, glossitis, oral ulcerations, loss of taste sensations, opportunistic infections and several other conditions dependent on these. One of the recent theories about complications in DM is the contribution of reactive oxygen radicals. Paraoxonase (PON1) is an enzyme that is synthesized in liver and having the capability of hydrolasing the active metabolite of an insectisid, parathion. Previously it was shown that there are two polymorphic areas on the PON1 gene: one causing a Leuu2009→u2009Met substitution at 55th position, the other causing Glnu2009→u2009Arg at the 192nd position. We investigated the differences in PON activities related to the oral lesions in Type 2 diabetics and control subjects to see their relationships with PON1 activity levels and the two main gene polymorphisms of PON1 genes, PON1 192 and PON1 55. We had 51 patients and 53 healthy subjects used in the study. PON activity was significantly decreased in Type 2 DM group compared to the control group. Neither PON1 192 nor PON1 55 genotypes had any differential effect on PON1 enzyme activity levels in either group. However, we found that PON1 55 M allele carriers had greater risk for general periodontal and/or gingival problems. Copyright

PCR-RFLP and Real-Time PCR Techniques in Molecular Cancer Investigations

The polymerase chain reaction (PCR) is a rapid scientific method for generating a 106-107fold increase in the number of copies of discrete DNA or RNA sequences (Boehm,1989; Imboden et al,1993). The use of PCR technology has greatly increased the ability to study on genetic material. PCR is a rapid and reliable molecular biology technique that allows quick replication of mainly DNA, the starting material can be a single molecule of rRNA or mRNA. It was developed by Kary Mullis in 1983, and he was awarded the Nobel Prize in 1993. PCR method is useful in situations of limited amount of DNA sample as in forensics, prenatal testing, because it amplifies a single or a few copies of DNA creating millions of copies of the region(1). The ability to quickly produce large quantities of genetic material has enabled significant scientific advances including DNA fingerprinting and sequencing of the human genome. As PCR technology allows taking specimen of genetic material even from just one cell, copy its genetic material several times, this facilitates genetic studies. Currently, besides research purposes, PCR technology is heavily used in diagnosis and patient management especially for viral diseases such as AIDS and hepatitis. Other than detection of infectious organisms, this technology is also useful for determination of genetic polymorphisms or mutations of individuals (Stahlberg,2011).