THE TRANSFERRIN RECEPTOR - ITS DIAGNOSTIC-VALUE AND ITS POTENTIAL AS THERAPEUTIC TARGET

Transferrin receptors are present on almost all mammalian cells. The r eceptor participates in the cellular acquisition of iron from transfer rin by receptor-mediated endocytosis. Receptor abundancy is generally regulated by two factors: i) cellular iron status and ii) cell growth. These two factors form the basis for the utilization of transferrin r eceptor determination as a diagnostic tool. In the assessment of body iron status and erythropoietic activity the measurement of circulating transferrin receptor has proved to be of value as a measure of mild t issue iron deficiency, to distinguish iron deficiency anemia from the anemias of chronic disease, and as a sensitive index of iron deficienc y during pregnancy. Histochemical analysis of the presence and abundan cy of the transferrin receptor will continue to serve as an additional tool in special cases to distinguish between malignant and normal cel l growth, and to provide additional information about the biological b ehaviour of tumor cells. Finally, die transferrin receptor holds a pot ential as a target for direct and indirect drug delivery in the therap y of malignant cell growth.