Biochemical activity in the metastatic lesions of neuroblastoma.

Catecholamine biosynthesis in tumor cells was studied in four patients, who expired from disseminated neuroblastoma. 1. The activity of tyrosine hydroxylase was detected in tumor tissues of all but one patient. 2. Dopamine-beta-hydroxylase activity was assayabel in almost all tissues, except in the primary tumor of one patient. 3. The enzyme activities in the metastatic lesions were at the same levels in two cases, but much higher in the other two cases, as those in the primary tumours. 4. It was learned that the urinary excretion of vanilmandelic acid (VMA) and homovanillic acid (HVA) in these patients reflects the tissue levels of catecholamine synthesizing enzymes as well as the tumor mass.