Demonstration of the transferrin receptor in human breast cancer tissue. Potential marker for identifying dividing cells.
A transferrin receptor was demonstrated in tumor tissue from 10 patients with breast carcinoma and one patient with breast sarcoma. Binding studies were conducted by measuring the amont of 1251-transferrin binding to microsomal preparations of the tumor tissue. Elevated levels of specific transferrin binding were found in the tumors with a range of 11-35% of bound transferrin, whereas microsomes prepared from non-neoplastic breast tissue samples bound only 2.3% and 2.4% of the transferrin. Scatchard analysis of binding studies conducted with tissues from a breast cancer and from a breast sarcoma indicate that the receptor has a Ka = 9.0 x 10(8)M. The binding site is specific for transferrin, as studies show that non-radioactive transferrin displaced labelled transferrin, while human IgG and human albumin did not. The receptor-transferrin complex was precipitated from a detergent extract of the breast sarcoma with antiserum to human transferrin. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis of the immunoprecipitate gave a polypeptide of M 90,000 daltons, which is of similar molecular weight found for the putative transferrin receptor in all of a series of human cultured cell lines previously examined.
D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division; D002462:Cell Membrane / Q000378:metabolism; D005260:Female; D006801:Humans; D008861:Microsomes / Q000378:metabolism; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000302:isolation & purification*; D011990:Receptors, Transferrin; D014168:Transferrin / Q000378:metabolism*
D011956:Receptors, Cell Surface; D011990:Receptors, Transferrin; D014168:Transferrin