Expression of p27(KIP1) and cyclin D1, and cell proliferation in human pterygium

Abstract

Background: The pterygium is a growth onto the cornea of fibrovascular tissue that is continuous with the conjunctiva, whereas the mechanisms of cell proliferation in pterygium epithelium are unknown. Aim: To analyse the histopathology and the expression of cell cycle-related molecules in pterygium tissues. Methods: Seven pterygia were surgically removed using the bare-sclera procedure, and three normal bulbar conjunctivas were also obtained. Formalin-fixed, paraffin-wax-embedded tissues were analysed by immunohistochemistry with antip27(KIP1), cyclin D1 and Ki-67 antibodies. Results: Conjunctival epithelium consisted of several layers of round cells with a few goblet cells. Nuclear immunoreactivity for p27(KIP1) was noted in many normal epithelial cells, where cyclin D1 and Ki-67-positive nuclei were intermingled. A variety of goblet cells were located in the superficial layer of the pterygium head as well as those of the body epithelia. Several pterygium epithelial cells were p27(KIP1) positive, whereas nuclear immunoreactivity for cyclin D1 and Ki-67 was detected in many epithelial cells. By contrast, immunoreactivity for p27(KIP1), cyclin D1 and Ki-67 was hardly detected in the pterygium stroma. Conclusion: It is suggested that pterygium growth and development are associated with the proliferation of epithelium, which is possibly involved in the expression of cell cycle-related molecules.

Proliferative and migratory aptitude in pterygium

“…This is in accordance with the higher expression of E-cadherin and -catenin in the head than body region (Kase et al 2007a). In addition, proliferation-associated p27 Kip1 , cyclin D1, Ki-67 and CD30 were detected in the pterygium epithelium; however, no spatial identiWcation was explored (GarWas et al 2009;Kase et al 2007b). …”

Molecular Basis of Pterygium Development

“…Pterygium basal epithelial cells exhibit molecular markers that are associated with an increased proliferation rate and low or negligible apoptosis, 5,93 suggesting that the pathways related to proliferation play key roles in pterygium formation.…”

Cultivation and characterization of pterygium as an ex vivo study model for disease and therapy

“…The proliferation marker Ki-67 has been found to be overexpressed in the epithelial cell layer of pterygium rather than in the stromal fibroblasts, in particular, the head and the body parts compared to the healthy conjunctiva. Accordingly, corneal invasion by the pterygium might be associated with proliferation of the epithelium, although it is clear that fibroblasts play important role in epithelial-mesenchymal interactions [6,[20][21][22]. Ki-67 has also been expressed in conjunctival and eyelid tumours [23], the positivity of which was low in the pterygium graft containing cultures, which was additionally five times less expressed in the multi-layered outgrowing tissue.…”