[S-100 beta protein in serum, a tumor marker in malignant melanoma-- current state of knowledge and clinical experience].

S100 is an acidic-calcium-binding protein, composed as a heterodimer of two isomeric subunits alpha and beta and was first described in cells of neuroendocrine origin. It plays an important role in various cellular processes such as cell differentiation and proliferation and interacts with the tumour suppressor gene p53.S100 is also present in melanoma cells and its immunhistochemical detection is widely used in the histopathological diagnosis of malignant melanoma. S100 has been detected in the serum of patients with malignant melanoma and many clinical studies have been performed to establish this protein as a tumor marker in different stages of the disease. The data suggest that S-100 beta-protein in serum of patients with malignant melanoma could be an independent prognostic marker and an additional clinical parameter for progression of metastatic disease and serological monitoring during systemic therapy. However there are patients in stage of lymph node- or systemic metastasis with negative S-100 beta-serum levels and no correlation to the course of disease. Our results confirm the findings for patients in stage III/IV. However, the percentage of S-100 beta-positive patients in stage III/IV is lower than reported in the literature, if repeatedly positive samples are excluded from statistical analysis. For monitoring in stage I and II it seems to be not helpful.