DETECTION OF MAGE-4 PROTEIN IN SERA OF LUNG-CANCER PATIENTS

We investigated the level of MAGE-4 protein in sera of patients with p rimary lung cancer to understand better the biological roles of the MA GE proteins. MAGE-4 protein was detected as a non-degraded form in bot h the supernatant of a MAGE-4(+) tumor cell line and in a patient's se rum. Serum level of the MAGE-4 protein in lung cancer patients (n = 10 0, mean = 1.17 ng/ml) was significantly higher than that in either pat ients with benign pulmonary diseases (n = 80, 0.33 ng/ml) or healthy d onors (n = 68, 0.32 ng/ml). It was higher than the cutoff level (1.15 ng/ml) in 34 of 100 cancer patients, but not in anyone in the other gr oups.