Serum ferritin as a guide to therapy in neuroblastoma.

Elevated serum ferritin levels without a corresponding increase in tissue iron storage have been observed in patients with certain cancers. Increased synthesis of ferritin by cancer cells has also been reported. In order to see whether similar phenomena occurred in patients with neuroblastoma, we have screened serum ferritin levels in 58 children with neuroblastoma by counterelectrophoresis using antibody to human ferritin. Increased ferritin levels in serum, positive by counterelectrophoresis (greater than or equal to 400 ng/ml), correlated well with the presence of active disease (p less than 0.001 by Fisher's exact 2 X 2 test). A longitudinal study of serum ferritin levels in 34 of the 58 patients showed the same association of elevated serum ferritin with active disease; a return of ferritin levels to the normal ranges coincided with remission. Primary neuroblastoma tumors and cells from neuroblastoma cell lines contained ferritins with the electrophoretic characteristics different from normal liver ferritin. Supernatant fluids from six neuroblastoma cell lines grown in culture also contained ferritin. These findings suggest that the increased ferritin in the serum of patients is derived from the tumor. The serum ferritin level could be used as indicator of disease activity and as a guide to therapy.