We would like to thank Kase et al for their interesting report1 on p27 and cyclin expression in pterygium. The authors have reported in table 11 that cyclin D was upregulated and p27 downregulated in pterygium, and concluded that a disorder of epithelial cell proliferation or cell cycle was involved. However, several important issues have not been addressed. We would like to highlight three points:

1. p27 is usually regarded …