Shared carbohydrate antigenic determinant between the myelin-associated glycoprotein (MAG) and lung cancers. An immunohistochemical study by an anti-MAG IgM monoclonal antibody.

An immunochemical study has shown that monoclonal anti-myelin-associated glycoprotein (MAG) antibodies identify some membrane glycoproteins from cell lines of small cell lung cancer. We investigated immunohistochemically 85 specimens of lung cancer from resection and autopsy using one of the monoclonal antibodies against MAG. One adenocarcinoma was highly reactive with the anti-MAG antibody, and in three small cell carcinomas immunostained tumor cells were distributed either singly or in occasional small clusters. These results show that a shared antigenic determinant with MAG appears on the tumor cells. MAG is believed to play the role of antigen in the development of carcinomatous polyneuropathy, and contributes to cancer development by its reduction of natural killer (NK) cell activity.