1. Division of Endocrinology and Diabetes, Department of Medicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany
2. Core Unit Clinical Mass Spectrometry, Central Laboratory, University Hospital Würzburg, 97080 Würzburg, Germany
3. Comprehensive Cancer Center Mainfranken, University of Würzburg, 97080 Würzburg, Germany