Neutrophil Gelatinase-Associated Lipocalin Is a Marker for Dysregulated Keratinocyte Differentiation in Human Skin

The study investigated the expression of Neutrophil gelatinase‐associated lipocalin (NGAL) in human skin during embryonic development, in normal adult skin, and in skin with inflammation and neoplastic transformation. NGAL was found to be regulated in a spatio-temporal pattern during embryogenesis, initially appearing in the interfollicular epidermis and later receding to hair follicles. In normal adult skin, NGAL was associated only with hair follicles. However, in skin disorders with dysregulated epithelial differentiation, such as psoriasis and squamous cell carcinoma, NGAL was strongly induced in the epidermis, particularly in areas of parakeratosis. This suggests that NGAL is a marker for disturbed terminal differentiation in keratinocytes and may play a role in epithelial differentiation pathways.