Differential Expression of Sox2 in Human Ocular Surface and Its Implication in Pterygium Pathogenesis.

INTRODUCTION: The precise etiology and molecular mechanisms underlying pterygium pathogenesis remain poorly understood, and the expression pattern of pluripotency-associated transcription factor SOX2 in human ocular surface has not been fully characterized. Therefore, we aimed to investigate the expression profile of SOX2 and its potential role in pterygium formation. METHODS: We thoroughly investigated the expression of SOX2 in the cornea, limbus, healthy conjunctiva and pteyrigium by immunohistochemistry, immunocytochemistry and RT-PCR. RESULTS: We found that SOX2 is aberrantly expressed in different cellular layers of cornea, limbus and conjunctiva in human ocular surface tissues. Comparative analysis further revealed a sustained elevated SOX2 expression in the pterygium tissues compared with healthy conjunctiva. This increased SOX2 expression was accompanied by upregulation of Ki67 but not CK15. CONCLUSIONS: Our results suggest that SOX2 is expressed at varying levels in human ocular surface tissues. Also, we report, for the first time, that SOX2 may play a regulatory role in the development of pterygium by promoting cellular proliferation during the abnormal extension of conjunctival tissue onto the corneal surface.