POSSIBLE FUNCTION OF CEA AS CELL-CONTACT INHIBITORY MOLECULE

Ever since it was discovered that CEA, as member of the CEA-gene famil y, is part also of the Ig-supergene family, to which molecules involve d in cell interactions like cell adhesion or cell recognition belong, great efforts were made to prove that CEA is also an adhesion molecule . At present this seems to be an accepted fact. In the present study w e advance a different theory which is based on the expression pattern of CEA during ontogeny and in malignancy and which is suggestive of CE A functioning more as a signal protein prohibiting further cell/cell c ontact rather than as an adhesion molecule. In the malignant state the expression of this molecule on the surface of tumor cells would facil itate migration and motility, i.e. metastases formation. Furthermore i t would prevent a tight contact between cytotoxic effector cells and C EA expressing target cells.