Ferritin was extracted from human
hepatocellular carcinoma tissue and purified using column chromatography, gradient gel electrophoresis and
cadmium sulphate crystallization.
DEAE cellulose chromatography showed a difference between
hepatoma and normal liver
ferritin, indicative of a more
acidic isoferritin profile in the tumour. Column-purified and crystalline
ferritin and that remaining in the mother-liquor after crystallization was subjected to isoelectric focusing.
Hepatoma ferritin showed higher concentrations of acidic isoferritins than liver
ferritin. This was most obvious with mother-liquor
ferritin, as crystallization tended to select out more basic isoferritins. Subunit analysis of
hepatoma and liver
ferritin showed a higher proportion of heavy subunits in the tumour
ferritin, in keeping with the presence of acidic isoferritins. An antibody against
hepatoma mother-liquor
ferritin was raised in rabbits. However,
hepatoma ferritin proved to be antigenically identical with normal liver
ferritin, and we were thus unable to develop a specific radioimmunoassay for
hepatoma ferritin.