Associations of ICOS and PD.1 Gene Variants with Colon Cancer Risk in The Iranian Population

Document Type: Research Articles

Authors

1 Gastroenterohepatology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.

2 Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.

3 Colorectal Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.

4 Fasa University of Medical Sciences, Fasa, Iran.

Abstract

Background: Positive and negative co-stimulatory molecules are important factors determining the outcome
of immune responses to the presence of tumors. Since co-stimulatory molecule expression may be affected by gene
polymorphisms, we aimed to investigate associations between variants of PD.1 and ICOS and susceptibility to colon
cancer. Material and methods: ICOS (-693A/G), ICOS (+1720C/T) and PD.1 (-538G/A) gene polymorphisms were
evaluated by the PCR-RFLP method in 76 colon cancer patients and 73 healthy controls. Results: The frequencies
of the GG genotype and the G allele at position -693 of the ICOS gene were significantly higher in the patient group
(P=0.014 and p=0.0002), while the AA genotype was significantly more common in controls (P=0.0016). At position
-538 of PD.1, GG genotype and G allele frequencies were higher in the patient group (PAA and also AG genotypes significantly predominated in controls (Pand alleles of ICOS at position +1720. Frequencies of GCG and GTG haplotypes were higher in patients compared
to those of controls (P=0.016 and P<0.0001), while, frequencies of GTA, ATA and ATG haplotypes were higher in
controls (P=0.0017, Ppatients compared to controls (P=0.0147 and P=0.0071). Conclusion: Our study clarified that PD.1 (-538G/A) and
ICOS (-693A/G) gene polymorphisms can be considered as genetic risk factors for the development of colon cancer
among Iranian patients.

Keywords

Main Subjects