Abstract
We have established an ELISA system for assessing the tumor-associated antigen MK-1 and determined serum levels of MK-1 in cancer patients, which had scarcely been elucidated. MK-1 was increased in sera of about 10 percent of the patients tested, while it was undetectable in sera of healthy volunteers, suggesting that MK-1, a transmembrane protein, can be released from tumor cells in certain cases. This should be taken into consideration when MK-1 is used as a target molecule for in vivo immunodetection or immunotherapy.
