[Blood concentration of laminin gamma2 chain in patients with head and neck cancer].

Laminin gamma2 chain (LN gamma2), expressed in human cancer cells and correlated with cancer malignancy, is cleaved by proteases and secreted into circulation. We measured the blood concentration of LN gamma2 in patients with head and neck cancer by an immuno-fluorescence assay using monoclonal antibodies against human LN gamma2. The normal blood concen- showed normal LN gamma2 concentration less than 50 ng/ml and 20 (33%) increased concentration exceeding 50 ng/ml. The relative ratio of the number of patients who showed increased LN gamma2 concentration correlated with the clinical stages of cancer. The blood concentration of LN gamma2 in 24 who initially showed normal concentrations did not change after radical treatments. Five who initially showed increased LN gamma2 concentration showed decreased concentration of less than 50 ng/ml after radical treatment. Four showed increased LN gamma2 concentration after treatment, and presented residual cancer, which killed them. Three of the 4 patients showed marked increase in LN gamma2 concentration exceeding 100 ng/ml and developed multiple distant metastases to the lung, liver, bone, and skin. The blood concentration of LN gamma2 in patients with head and neck cancer may thus indicate the amount of highly malignant cancer cells expressing LN gamma2. The blood concentration of LN gamma2 could therefore serve as a new tumor marker that might indicate the malignancy of and efficacy of treatments for head and neck cancer.