Pterygium is a chronic condition characterized by the encroachment of a fleshy triangle of conjunctiv al tissue into the cornea. Epidemiological evidence suggests that UV irradiation plays the most important role. In our previous studies, abnormal levels of the p53 protein being found in pterygial epithelium. Mutations in the p53 gene could lead to tumor formation and have been found in various types of tumor cells. We assume that pterygium may have the similar mechanism in oncogenesis. However, the most different in pterygial cell and other cancer cells is that pterygium does not have the activity of invasion and metastasis. Recently, many studies revealed that E-cadherin expression decreases in many tumors, and it may be a marker for tumor metastasis and prognosis. We already known that E-cadherin has no bioactivity until binding on cell membrane as a complex with α-catenin、β-catenin and p120ctm . It has been well understood that ligand can active EGFR pathway and phosphorylate ceterin to digest E-cadherin. β-catenin is one part of Wnt family in signal transduction. Unconjugated β-catenin in cytoplasma will interactive with Wnt and get into cell nucleus, resulting in cell proliferation and tumor cell metastasis. In our study, we use immunohistochemistry to analyze the E-cadherin in 30 pterygial samples and the unexpression rate up to 40%. Therefore, we try to using immunohistochemistry to analyze the protein expression in E-cadherin、α-catenin、β-catenin and p120ctm in pterygium, to investigate if the abnormal expression in E-cadherin complex will cause cell proliferation. E-cadherin signal pathway not only causes cell proliferation but also changes the activity of cell invasion. However, E-cadherin signal pathway only results in cell proliferation but no metastasis in pterygium. To investigate this, in our second year plan, we use cultured pterygium cell and analyze the process of the Wnt signal pathway, also analyzing the gene expression by PCR. We try to investigate the role of E-cadherin and Wnt in pterygium formation, also compare with other tumor cell and find out the difference between each other. Our study result could give more information about the pterygium formation, and also offer a solution in suppressing tumor metastasis.
