To analyse the concentration catecholamines in thrombocytes of patients with clear cell renal cell carcinoma and low grade neuroendocrine tumours.~To compare these concentrations with the concentrations catecholamines in thrombocytes of healthy controls.~To analyse the concentration catecholamines in thrombocytes of patients with clear cell renal cell carcinoma and patients with low grade neuroendocrine tumours with and without medication.
The primary objective of this study is to analyse the concentration dopamine and serotonin in thrombocytes of patients with renal cell carcinoma and neuro-endocrine tumours compared to the concentrations of these catecholamines in healthy volunteers. The concentration dopamine and serotonin in thrombocytes with and without medication will also be evaluated.