Gene expression of neuronal nitric oxide synthase and adrenomedullin in human neuroblastoma using real-time PCR

The objective of our study was to assess the gene expression of the antipro liferative systems neuronal nitric oxide synthase (nNOS) and adrenomedullin (AM) in human neuroblastoma. A novel real-time PCR method was evaluated us ing neuropeptide Y (NPY) for validation. Glyceraldehyd-3-phospate dehydroge nase (GAPDH) and NPY gene expression in neuroblastomas of 50 patients were measured in parallel by competitive quantitative and TaqMan real-time RT-PC R, AM and nNOS mRNA were determined by real-time PCR. Our results-showed a linear relationship between competitive quantitative and real-time RT-PCR m easurements of NPY and GAPDH (r = 0.87 and r = 0.92, respectively). AM and nNOS mRNA was found in all tumor samples. AM/GAPDH mRNA increased with high er differentiation according to Shimada (p = 0.013). There was no relation between MYCN amplification nor with the tumor stage (p = 0.78 and p = 0.30; respectively). AM/GAPDH did not relate to recurrence or death in a 5-year follow-up period. Neuronal NOS/GAPDH expression did not relate to any biolo gical or clinical parameter of prognosis or differentiation. Similar result s were obtained when the neuronal marker protein gene product 9.5 (PGP9.5) was used to normalize mRNA concentration. In conclusion, TaqMan real-time P CR appears to be a reliable method to quantify gene expression in neuroblas tomas. Adrenomedullin mRNA in neuroblastoma is linked to tumor differentiat ion but not to prognostic markers. Int. J. Cancer 88: 172-175, 2000. (C) 20 00 Wiley-Liss, Inc.