E-cadherin promoter hypermethylation may contribute to protein inactivation in pterygium
Abstract
Background
Our recent reports indicated that the molecular changes of pterygium are like tumor cells. We assume that pterygium may have this similar mechanism in oncogenesis. Some studies have revealed that E-cadherin associated protein expression decreases in many tumors and pterygium. It may be a marker for tumor metastasis and prognosis. However, there were limited studies examining the reason for E-adhesion protein inactivation in pterygium. Therefore, the aim of this study was to analyze the association of E-cadherin promoter hypermethylation with protein inactivation in pterygium tissues.
Material and Method
The E-cadherin methylation-status and the expression of E-cadherin and β-catenin protein were studied using methylation-specific PCR and immunohistochemistry respectively on 120 pterygial specimens and 30 normal conjunctivas.
Result
There were 79 (65.8%) pterygial specimens positive for E-cadherin protein expression and 41 (34.2%) specimens were negative. The E-cadherin staining was limited to the membrane of the epithelial layer. Hypermethylation of E-cadherin gene promoter was detected in 32 (26.7%) of the 120 pterygial specimens. There was a reverse correlation between E-cadherin gene promoter hypermethylation and E-cadherin protein expression (p<0.0001). In the E-cadherin negative group, aberrant localization of β-catenin was higher.
Conclusion
Our study demonstrates E-cadherin gene promoter hypermethylation suppresses the expression of E-cadherin protein. Moreover, loss of E-cadherin protein may contribute to aberrant localization of β-catenin. These data provide evidence that methylation exists in pterygium and may play a role in the development of pterygium.
