S100B and neoplasm: Thus, early diagnosis and treatment of malignant melanoma is extremely important to improve survival.5 As an acidic calcium-binding protein, S-100B is the first marker to specifically label tumor cells of malignant melanoma and its value in the early diagnosis of malignant melanoma has been fully confirmed.6 When the level of S-100B in serum exceeds 0.5 ng mL−1, it is generally considered to be a pathological concentration.