Background: The Wnt (Wg/Wnt) signaling cascade plays an important role in tumorigenesis. Our previous report indicated that aberrant localization of beta-catenin proteins was a feature of pterygia. Therefore, this study aimed to analyze the association of beta-catenin protein and expression of a downstream gene, cyclin D1, in pterygial tissues. Methods: Using immunohistochemistry, beta-catenin and cyclin D1 protein expression was studied, in 150 pterygial specimens and 30 normal conjunctivas. Results: Seventy-three (48.7%) and 60 (40.0%) pterygial specimens tested positive for beta-catenin and cyclin D1 protein expression, respectively. Cyclin D1protein expression was significantly higher in beta-catenin-nuclear/cytoplasmic positive groups than in beta-catenin membrane positive and negative groups (p<0.0001). In addition, cyclin D1 expression was significantly higher in the fleshy group than in the atrophic and intermediate groups (p=0.006). Conclusions: Our study demonstrated that beta-catenin expressed in nuclei/cytoplasm increases cyclinD1 protein expression, which invokes pterygial cell proliferation.
