Assessment of Promoter Hypermethylation and Expression Profile of P14ARF and MDM2 Genes in Patients With Pterygium.

Abstract

Pterygium is a fairly general condition in many regions of the world. The cause of this abnormality is still ambiguous. However, recent findings suggest that pterygium is a benign progressive tissue and not a degenerative disorder. The main goal of our study was to investigate the effects of P14 and MDM2 promoter methylation on the risk of pterygium. In this study, the DNA of 81 primary pterygium and 75 normal conjunctiva tissues was extracted and modified for the assessment of methylation of P14 and MDM2 promoters by methylation-specific polymerase chain reaction (MSP). We also estimated the mRNA expression levels of these genes in 23 pterygium and 18 normal conjunctiva tissue samples using real-time quantitative reverse transcriptase polymerase chain reaction. The frequency of methylation for P14 was 92.6% for cases and 97.3% for controls. MDM2 gene methylation at the promoter site was 39.5% and 72.0% for pterygium and normal conjunctiva tissues, respectively. So statistically, a significant relationship between MDM2 gene promoter methylation and the risk of disease was found (odds ratio=5.3; 95% confidence limit, 2.6-10.8; P<0.0001). In addition, the expression of MDM2 gene has increased in pterygium (1.371548±0.6727) in comparison with conjunctiva tissues as control (1.20621±1.0) (P<0.05), but it was not significant for P14 gene. Our results have indicated that hypomethyaltion and overexpression of MDM2 gene take place in patients with the pterygium. To confirm the presented data, suggesting further studies with a larger sample size in various genetic populations.