Ferritin-bearing lymphocytes in patients with cancer

Ferritins, a group of isomeric proteins that have important functions in iron metabolism and storage, have been demonstrated to be carcinoembryonic antigens. It has been recently shown that a subpopulation of lymphocytes from the peripheral blood of patients with Hodgkin's disease or breast cancer bear ferritin on their surface membranes. In view of the potential diagnostic and prognostic value of ascertaining the number of ferritin-bearing lymphocytes, the authors developed a simple indirect immunofluorescent technique for identifying them and used this technique to examine the peripheral blood lymphocytes of 44 patients with carcinomas of the head and neck (26), colon (14), and lung (4). It was found that patients with cancer had a mean percentage of 10% ferritin-bearing lymphocytes in their peripheral blood as compared with 3.1% in controls. Ferritin binding did not appear to be influenced by a cell's capacity to form sheep erythrocyte (E) rosettes since no correlation could be found between the percentages of lymphocytes bearing ferritin and those forming three different varieties of E-rosettes. There appeared to be no correlation of the percentages of ferritin-bearing lymphocytes with clinical staging except for a small, but significant (P less than 0.05), increase in the number of patients with head and neck cancer and nodal metastases. Although the functional significance of ferritin-bearing lymphocytes is currently unknown, the appearance of this subpopulation of cells in the blood appears to be associated with cancer. This assay may prove to be useful as a diagnostic tool, as a prognostic tool, or as a means of identifying patients at a risk for developing cancer and, therefore, it deserves further exploration.