Molecular aspects of the plasma membrane in tumor cells.

Abstract

It is well known that malignant neoplastic cells are different in their surface properties from their normal counterparts. 1,ZO) Unusual cell-to-cell interactions in the malignant cells are the most important behavior for distinguishing them from their normal counterparts and also for determining the prognosis of patients suffering from cancer. Decrease in or loss of the cell's ability of (1) sorting out each other, (2) mutual adhesiveness, (3) intercellular communication by exchange of small molecules, (4) contact inhibition of both growth and movement affecting the cell density of in vitro culture, and changes in the surface antigenisity, including changes in surface arrangement of various receptors, have been considered hitherto as specific abnormalities in the surface properties of malignant cells. A change in the association of plasma membrane with cytoskeletal structures also seems to have a close relation with these abnormalities. Almost all the details of the molecular mechanisms of these abnormalities, however, remain obscure. In this paper, to clarify some of these molecular mechanisms, we will elucidate some of the molecular events and discuss them in connection with abnormalities of the surface properties in tumor cells based on our analytical results obtained from the plasma memberane of tumor cells.