Transferrin receptors in human cancerous tissues

The clinical significance of radioreceptor assay for transferrin receptors of human cancerous tissues was evaluated. Fresh surgical specimens from various carcinoma tissues were solubilized with 1% Triton X-100 and the extracts were mixed with 125I-labelled diferric transferrin. The free transferrin and the receptor-bound transferrin were separated by 15% polyethylene glycol precipitation. The % specific transferrin binding to gastric, colonic, lung and mammary carcinoma tissues ranged between 3.9 and 13.9%, whereas those for normal stomach and colon were less than 2%. The concentrations of transferrin receptors in these cancerous tissues ranged between 3.7 and 28.3 pmole/g tissues. It was concluded that the amounts of transferrin receptors were significantly increased in all of the tumor tissue extracts examined and may thereby provide a useful marker for the diagnosis of malignancies.