HPLC-mass spectrometry method for quantitative detection of neuroendocrine tumor markers: vanillylmandelic acid, homovanillic acid and 5-hydroxyindoleacetic acid

BACKGROUND: The urinary excretion of vanillylmandelic acid (VMA), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) can be increased in the presence of neuroblastic and carcinoid tumors. The former is characterized by defective catecholamine metabolism which results in high urinary levels of VMA and HVA. The latter shows an altered metabolism of tryptophan and an increased synthesis of serotonin, producing high 5-HIAA urinary concentrations. METHODS: We describe an HPLC-tandem mass spectrometric method for the simultaneous quantification of VMA, HVA and 5-HIAA in human urine. The chromatographic separation is performed on a reversed-phase C18 column. Instrumental analysis is performed on a Q-Trap 2000 triple quadrupole/ion trap mass spectrometer. RESULTS: The method is fast and does not require sample pre-treatment. Multiple calibration curve exhibited consistent linearity and reproducibility. Linear responses were observed in the concentration range 0-50 mg/l for each analyte. Limits of detection were 0.001 mg/l for VMA, 0.015 mg/l for 5-HIAA and 0.050 mg/l for HVA with a signal-to-noise ratio of 3. Limits of quantification were 0.005 mg/l for VMA, 0.050 mg/l for 5-HIAA and 0.1 mg/l for HVA with a signal-to-noise ratio of 10. CONCLUSIONS: This method can be proposed as a tool for neuroendocrine tumor markers detection.