Value of serum S-100B for prediction of distant relapse and survival in stage III B/C melanoma

Background: The biochemical marker serum S-100B has been proven to reflect the stage of melanoma and to be useful for disease monitoring and prediction of survival, mainly in stage IV disease. For stage III melanoma, limited data are available and its predictive value for relapse is unknown. Serum S-100B was evaluated prospectively for monitoring response and its predictive value for relapse and overall survival in stage IIIB/C melanoma patients. Patients and Methods: Treatment consisted of one cycle of neoadjuvant and adjuvant chemo(immuno) therapy, around surgery. S-100B was measured at enrollment and prior to and following surgery. The levels of S-100B in serum were compared to the pattern and intensity of the expression of S-100B in the melanoma tissue. Results: Some patients with normal initial S-100B values (n=18) showed responses (3 complete remission and 2 partial remission), in contrast to patients with elevated S-100B values. Distant relapse within one year was found in 11/23 (48%) patients with increased S-100B versus 2/18 (11%) patients with a normal value (p=0.01). Overall survival was decreased in patients with increased S-100B compared to those with normal S-100B (p=0.02). Correlations between the pattern and intensity of S-100B expression in the tumor specimen and the value of serum the S-100B did not reach statistical significance. Conclusion: Serum S-100B is a valuable biomarker for the evaluation of response to treatment and prediction of early distant relapse and survival in stage IIIB/C melanoma. The marginal correlation between serum S-100B values and expression of S-100B in the tumor specimens needs further study.