CDKN1B and pterygium: In the present study, we investigated if small interfering RNA (siRNA)-mediated gene silencing of S phase-kinase-interacting protein 2 (Skp2) can be employed to inhibit protein 27 kinase inhibition protein 1 (p27kip1) down-regulation in pterygium fibroblast cells (PFC) in vitro and in vivo.