Increased CCL17 serum levels are associated with improved survival in advanced melanoma.

BACKGROUND: Prognostic factors of melanoma patients with distant metastases remain poorly established. This study aimed to compare the prognostic impact of putative serum biomarkers, namely S100B, YKL-40 or CCL17, in stage IV melanoma patients. PATIENTS AND METHODS: Serum concentrations were analyzed by ELISA. Disease-specific survival of 80 patients according to S100B, YKL-40 or CCL17 and clinical factors were calculated by univariate Kaplan-Meier survival and multivariate analysis. RESULTS: Low serum levels of S100B, high concentrations of CCL17 and female gender correlated with improved survival. A trend for favorable prognosis was observed for the M categories M1a/b versus M1c according to the AJCC classification. No correlation with survival was evident for YKL-40 serum levels and age. In multivariate analysis, S100B (HR 2.1; p = 0.005) and CCL17 (HR 1.8; p = 0.029) had independent prognostic impact. Patients with a combination of normal S100B and high CCL17 had a high chance for long-term survival, which was 43 % after 3 years. CONCLUSION: Serum levels of CCL17 and S100B represent independent prognostic markers for melanoma patients with distant metastases. These biomarkers were more powerful than the M category according to the AJCC classification to indicate overall survival. CCL17 represents a promising biomarker upon immune checkpoint blockade in melanoma.