The ROC curve analysis of the relationship between the serum concentration of S100A15 in the individuals with HS in Hurley stage III and in the individuals with HS in Hurley stage I revealed an AUC of 0.95 (95%CI for AUC: 0.86–1) (p < 0.0001). The gene discussed is S100A7A; the disease is histiocytic sarcoma.