Tissue Factor Expression In Human Pterygium

Abstract

Purpose: : A pterygium represents tumor-like characteristics such as proliferation, invasion and epithelial-mesenchymal transition (EMT). It has been demonstrated that tissue factor (TF) expression is relevant to the EMT in tumor cells, contributing to tumor progression. However, TF expression in pterygium has yet to be elucidated. In this study, we examined the expression and immunolocalization of TF in human pterygial and normal conjunctival tissues.

Methods: : Eight pterygia and three normal bulbar conjunctivas, surgically removed, were used in this study. Formalin-fixed, paraffin-embedded tissues were processed for immunohistochemistry with anti-TF and alpha-smooth muscle actin (α-SMA), a mesenchymal marker, antibodies. TF expression and co-localization with α-SMA were evaluated by double staining immunohistochemistry.

Results: : TF was expressed in all pterygial tissues examined. TF immunoreactivity was detected in the cytoplasm of pterygial epithelial cells. The number of TF-immunopositive cells (54.8%) in pterygial epithelial cells was significantly higher than in normal conjunctival epithelial cells (0%, p<0.001). TF was detected in α-SMA-positive or -negative pterygial epithelial cells.

Conclusions: : Our data demonstrated the marked expression of TF in the pterygial epithelial cells compared to normal conjunctiva, suggesting a potential role of TF in the pterygium pathogenesis. TF expression may be regulated by not only EMT but also other TF-related molecules.

Keywords: pterygium • immunohistochemistry