Inverse correlation between N-myc amplification and catecholamine metaolism in children with advanced neuroblastoma

The relationship between urinary excretion of catecholamine and/or its metabolites before the initiation of therapy and the genomic amplification of N-myc of the extirpated primary tumors was studied in 32 patients who had advanced neuroblastoma (stages III and IV). Values of vanillylmandelic acid, homovanillic acid, and noradrenaline excreted in urine were significantly higher in patients with 1 to 10 copies of N-myc (L-group) than in those patients who had more than 10 copies (H-group), whereas values of dopamine in urine were not significantly different between the groups. The ratio of urinary noradrenaline and dopamine was also significantly higher in the L-group. N-myc amplification, urinary excretion of vanillylmandelic acid and the noradrenaline/dopamine ratio significantly affected the prognosis. These data suggest that an inverse regulatory mechanism might be present between the N-myc amplification and catecholamine metaolism in patients who have advanced neuroblastoma, possibly at the level of gene and/or enzyme. These events would influence the prognosis. The main blockade of metabolism may be in the metabolic processes from dopamine to noradrenaline.