Limbal Dermoid Epithelium Shares Phenotypic Characteristics Common to Both Hair Epidermal and Limbal Epithelial Stem Cells

Purpose: To determine putative limbal epithelial stem cell marker expression in human limbal dermoids compared to stem cell niches in normal limbus and hair follicles of normal human dermis. Methods: Human limbal dermoids (n = 7), normal skin (n = 2) and normal limbal (n = 7) tissue were examined. Immunohistochemistry was performed on paraffin embedded specimens using automated and manual immunostaining with primary antibodies to CK15, CK14, Cadherin-P (CDH3), Wnt-3, Wnt-4, Wnt-5a, Dickkopf (DKK)-3, Sox-2, Sox-10, Sox-13, PEDF, NGFR p75 and beta-catenin. Results: Positive immunostaining was found for CK15, CK14, CDH3, NGFR p75, PEDF, Sox-2, Sox-10 and Wnt 4 in the basal dermoid epithelium, limbus and hair follicles. Suprabasal epithelium was immunostained with PEDF, Sox-2 and Wnt-4 in these tissues. The sebaceous and sweat glands, vascular endothelium and nerves of the limbal dermoid immunostained with PEDF and Sox-2. Sebaceous and sweat glands stained for Sox-10. DKK-3 immunostaining occurred in the dermoids' suprabasal epithelium and vascular endothelium but not in the limbus or hair follicle. Conclusion: Human limbal dermoids share a similar antigenic expression profile similar to the basal limbal epithelium and to the stem cell niche of hair follicles. This supports the notion that limbal dermoids could have properties in common with limbal and/or dermal epithelial stem cells.