The aim of this study was to investigate the presence of
lactotransferrin receptor on breast non-malignant SV-40 immortalized cells (HBL100 and NB54T), benign mastopathy immortalized cells (NPM14T and NPM21T1), hst oncogene transformed HBL100 cell line (tumorigenic HH9 cells) and
breast carcinoma cells (T47D, MCF7, VHB1, BT20 and MDA-MB 231). Flow cytometry analyses of the reversible binding of
lactotransferrin labeled on its
glycan moiety with
fluorescein indicate, for the first time, that all these epithelial breast cell lines, express a specific
lactotransferrin receptor. The binding parameters of [125I]-
lactotransferrin to non-malignant cells, hst oncogene transformed cells and benign mastopathy cells are of the same order of magnitude as those determined for activated lymphocytes and for cancerous breast cell lines, except for MDA-MB 231 cells. MDA-MB 231 cells bind
lactotransferrin with the lowest affinity and, in contrast to other analyzed breast cells, are not recognized by
antibodies directed against lymphocyte
lactotransferrin receptor. These results suggest that MDA-MB 231
lactotransferrin receptor is different from that characterized at the cell surface of other breast cells. In conclusion, since the
lactotransferrin receptor expression was not enhanced at the surface of cancerous cell lines and was not altered by the oncogene transformation of a normal cell (HBL100) to a tumorigenic cell (HH9), the
lactotransferrin receptor cannot be considered as a marker of
tumor progression.