[Serum S100B protein and stage of cutaneous melanoma: a prospective study].

OBJECTIVE: We searched for a correlation between serum S100B protein and cutaneous malignant melanoma stage, according to the American Joint Committee on Cancer staging system, and between elevation of serum S100B protein and development of metastasis.

PATIENTS AND METHODS: We conducted a prospective bicentric study for 20 months in 122 patients with malignant melanoma. LIA-mat(R) assay was used to determine serum S100B at each examination. The optimal cut-off value was determined from the ROC curve.

RESULTS: The optimal cut-off value to discriminate patients with metastases from patients in remission was 0.09 microg/l. Sensitivity was 46 p. 100 in patients with stage III and 86 p. 100 in patients with stage IV disease. The positive predictive value for stage III/IV was 77 p. 100 and the negative predictive value was 89 p. 100. Serial measurements were made in 56 patients. The serum S100B protein level was elevated in 69 p. 100 of the patients disclosing disease progression (9/13). In 44 p. 100 of the patients (4/9), serum S100B protein level rose within a delay of 3 months before new metastases were detected.

DISCUSSION: Our study confirms that serum S100B protein is a tumor marker for melanoma staging and follow-up. A rise in S100B protein precedes or reveals metastasis.