Localization of transferrin receptors (TFRs) in human non functioning thyroid nodules and in extranodular thyroid tissue.

In this research the TFR localization in non functioning human thyroid nodules and in the extranodular thyroid tissue, using an immunohistochemical technique, has been studied. For this study a monoclonal antibody (B3/25) against TFR and the peroxidase technique have been utilized. Moreover a morphometric comparative analysis was carried out based on the following parameters: 1) mean immunoreactive area for microscopic field, 2) mean value of immunoreactive follicular perimeter, 3) integrated optical density, 4) % of immunoreactive area on total examined area in nodular and extranodular tissue. The immunoreactivity was detected in some follicular cells in a number of follicles randomly distributed in the extra nodular tissue. As concern the non functioning thyroid nodules, the positivity was localized in the generality of the follicles both in the flattened epithelial cells of the larger follicles and in the cuboidal cells of the smaller ones. The morphometric parameters confirm a statistically significant difference of immunoreactivity between extranodular and nodular tissue. These results suggest that TF might play a role in the cellular proliferation of thyroid gland.