Ya Association of Paraoxonase-1(Q192R and L55M) gene polymorphisms and activity with colorectal cancer and   effect of surgical intervention

Nagwa S. Ahmed^a, Noha M shefik^b, Omar Abd.Elraheem^c and Saad-Eldin. A. Abou-Elnoeman^b

^a,b Departments of Medical Biochemistry, Faculty of Medicine. Sohag University, Sohag, Egypt,

^cGeneral Surgery Faculty of Medicine. Sohag University, Sohag, Egypt. ^a.cSohag

.^bTanta University, Egypt.

Corresponding Author’s Email. dr_nagwa69@yahoo.com

Accepted 21 December, 2014

Abstract

Background: Colorectal cancer (CRC) is the leading cause of cancer-related deaths. Oxidative DNA damage may contribute to the cancer risk. The antioxidant paraoxonase is an endogenous free radical scavenger in the human body. The aim of this study was to find association between preoperative and postoperative serum paraoxonase-1 (PON1) and arylesterase (ARE) activities in patients with newly diagnosed CRC and to determine (PON1) Q192R and L55M gene polymorphisms. Patients and Methods:  this study involved a total of 50 patients with newly diagnosed CRC and   80 healthy controls. PON1 and ARE activities were determined using an enzymatic spectrophotometric method. PON1 Q192R and L55M gene polymorphism was determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based restriction fragment analysis. The restriction enzyme AlwI was used to examine the Q192R polymorphism and Hsp92II for the L55M polymorphism. Significant differences in the PON1 Q192R polymorphism were found between patients and controls. The Q allele was more frequent in the patient group than in controls, while the R al­lele was more frequent in the control group. No significant differences were found in the L55M polymorphism. Additionally, there were no significant differences in L and M allele frequencies. The activities of PON1 and ARE lower in QQ and MM genotype, Conclusion: serum PON1 and ARE activities were significantly lower in CRC Patients compared to healthy subjects. The R allele may protect against colorectal cancer.

Keywords: colorectal cancer. Paraoxonase-1, Q192R and L55M gene polymorphisms.