Evaluation of Polymorphisms rs762624 and rs3176336 of CDKN1A Gene and Risk of Colorectal Cancer

Aims: Progressive loss of cell cycle control is an important feature on the colorectal cancer. CDKN1A gene encoded p21 protein that’s one of the cyclin-dependent kinase inhibitors, plays a key role in regulating the cell cycle. The aim of this study was to investigate associations of the CDKN1A gene polymorphism rs762624 and rs3176336 with risk of colorectal cancer in an Iranian population.
Methods: A case-controls study was conducted to investigate the association of polymorphism rs3176336 and rs762624, with colorectal cancer risk in Iranian population. In this study 150 cases of sporadic CRC and 150 healthy controls were recruited, genomic DNA were extracted from peripheral blood, the genotypes were determined using the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method and the result was validated by direct sequencing.
Results: The rs762624 frequencies of the AA, AC, and CC genotypes among cases were 9.3%, 74.7%, and 16%, respectively, while in controls genotype frequencies were 10%, 74%, and 16%, respectively. The rs3176336 frequencies of the AA, AC, and CC genotypes among cases were 29.3%, 18% and 52.7%, respectively, while in controls genotype frequencies were18%, 20%, and 62%, respectively. No association was found for the CDKN1A rs3176336 AT/AA genotype (Adjusted odds ratio (OR), 0.726, 95% confidence interval (CI), 0.365–1.443 for AT genotype; OR, 1.67, 95% CI, 0.754–3.702 for AA genotype) with risk of colorectal cancer, compared with the TT genotype. In our research, we could not found significant relation between stage of colorectal cancer and genotypes of rs762624 and rs3176336 polymorphisms (p=0.081, p=0.988).
Conclusion: Present data do not confirm association of rs3176336 and rs762624 polymorphisms with susceptibility of Iranian to colorectal cancer.