POSITRON EMISSION TOMOGRAPHY UTILIZING C-11 5-HYDROXYTRYPTOPHAN, PLASMA BIOCHEMISTRY AND NEUROENDOCRINE IMMUNOHISTOCHEMISTRY OF METASTATIC RENAL-CELL CARCINOMA

The aim of this study was to characterise metastatic renal cell carcin oma in 18 patients with positron emission tomography (PET) utilising C -11-5-hydroxytryptophan, plasma biochemistry and neuroendocrine immuno chemistry. Of these 18 patients, ten underwent the PET investigations. The standardised uptake values (SUVs) in hepatic deposits were higher than those in pulmonary lesions, with mean values of 3.15 and 2.35, r espectively. The immunohistochemical study included staining of 10/18 surgical tumour specimens with antibodies reactive with chromogranin ( Cg), neurone-specific enolase (NSE), and synaptophysin (Sy). In 17/18 patients, plasma measurements of the neuroendocrine peptides, CgA, CgB , pancreastatin, and serotonin, were performed. The results obtained i n this study show that PET with C-11-5-hydroxytryptophan, a precursor in serotonin synthesis in neuroendocrine cells, can be utilised to vis ualise primary renal cell cancer and its secondaries in vivo. The resu lts obtained also suggest that neuroendocrine differentiation may occu r in human RCC.