Prognostic significance of the hair follicle stem cell marker nestin in patients with malignant melanoma.

Nestin is an intermediate filament protein, and serves as a hair follicle stem cell and neural stem cell marker. Recent studies have suggested that nestin expression is also important for tumorigenesis. Previous reports from our laboratory have revealed that nestin is a marker of HMB-45-negative melanoma cells in dermal invasive lesions of nodular malignant melanoma. The present study examines nestin expression in malignant melanoma and investigates the relationship between nestin expression and prognosis in patients. We immunohistochemically stained 78 formalin-fixed and paraffin-embedded malignant melanomas for nestin, HMB-45 and S100 reactivity. We found that nestin, HMB-45 and S100 protein were detected in 56.5%, 88.4% and 100% of malignant melanomas, respectively. The 5-year survival rate of stage I and II nestin-positive cases was significantly decreased compared to the nestin-negative cases (p < 0.05). In addition, the 5-year survival rate exceeded 80% in nestin-negative malignant melanomas at all stages of tumor development. We conclude that nestin expression may be a predictor of poor prognosis in patients with malignant melanoma.