Beschreibung:
<jats:title>Summary</jats:title><jats:sec><jats:title>Background and objectives</jats:title><jats:p>Serum levels of S100B are standard in monitoring advanced malignant melanoma patients in order to discriminate progressive from non‐progressive disease. False‐positive results lead to distress among patients and increase the amount of cost‐intensive diagnostics. We therefore analyzed reported comorbid diseases as putative sources of excessive S100B release.</jats:p></jats:sec><jats:sec><jats:title>Patients and methods</jats:title><jats:p>Here, we report a single‐center experience on serum S100B levels in 2,664 blood samples from 1,113 stage IB to IV melanoma patients (AJCC) who presented for follow‐up examinations over a period of 24 months.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Overall, 295 (11 %) of patients developed disease progression. In patients with a high tumor load, the rate of false‐negative results was 30/185 (16 %). The rate of false‐positive results was 247/2369 (12 %). One hundred and six false‐positive results (69 %) compared to 46 true‐positive results (31 %) were found in patients with cardiovascular diseases such as arrhythmia (50/32) or previous myocardial infarction (22/14). Moreover, obesity (85/14), liver cirrhosis (31/10), migraine (18/2), chronic kidney disease (13/2), and previous stroke (11/1) were found to be associated with false‐positive S100B levels.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>Serum S100B is a useful quantitative biomarker in routine follow‐up of high‐risk melanoma patients. While false‐negative results are frequent in patients with low tumor load, false‐positive results are associated with several comorbid diseases and warrant careful reevaluation.</jats:p></jats:sec>