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

BACKGROUND: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.