THE ASSOCIATION BETWEEN EXONUCLEASE1 GENE POLYMORPHISM T>C (RS1635498) AND RISK OF SPORADIC COLORECTAL CANCER IN AN IRANIAN POPULATION

One of the important DNA repair systems is Mismatch Repair (MMR). Mutation
in this system can cause different types of cancer. Exonuclease1 (Exo1) is the only exonuclease
involved in the human MMR system. Since Exo1 plays a distinctive role in the MMR system, this
gene has gained a great intrest as a potential risk factor in Colorectal Cancer (CRC). Single nucleotide
polymorphisms (SNP) involve in increasing or decreasing the risk of CRC. In this study, to find a
potential biomarker of CRC, we investigated the association between SNP of Exo1 gene, rs1635498,
and risk of colorectal cancer in patients who had referred to Taleghani hospital.
Materials & Methods: This case-control study was performed on 111 cases and 121 healthy controls
who had been registered in Taleghani hospital of Tehran. Genotyping analysis was performed by
polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and use HPYCHVI
restriction enzyme.
Result: According to our finding, while TT genotype was selected as a refrence, the frequency percent
of TT, CT and CC genotypes in the patients were %90.1, %9.0, %0.9 and in the control group were
%92.6, %7.4 and %0.0. We observed no significant difference. The frequency percent of T allele in
the patients was %94.6 and in the controls were %96.3. Also the frequency percent of C allele were
calculated in the patients and controls group respectively %5.4 and %3.7.
Conclusions: The findings indicated that rs1635498 polymorphism in Exo1 gene isn't associated with
susceptibility to CRC. So, we conclude that this polymorphism doesn’t have significant role in
incresing or decreasing risk of CRC