Expression of the Hair Stem Cell-Specific Marker Nestin in Epidermal and Follicular Tumors

The study investigated the expression of hair stem cell-specific markers, particularly nestin, in normal human skin and various epidermal and follicular tumors. It was found that nestin, a marker for neural stem cells, was expressed in hair follicle stem cells and played a role in differentiating into various cell types. In normal skin, nestin was present in hair follicle cells below sebaceous glands, while in tumors, nestin was observed in trichilemmoma but not in basal cell carcinoma (BCC) or squamous cell carcinoma (SCC). The study suggested that trichilemmoma originated from nestin-positive/K15-positive/CD34-negative outer-root sheath cells, BCC from more mature nestin-negative/K15-positive/CD34-negative cells, and SCC from nestin-negative/K15-positive/CD34-negative keratinocytes in the epidermis.