SERUM PROTEINASE ACTIVITIES IN HEAD AND NECK SQUAMOUS-CELL CARCINOMA PATIENTS

Proteinases are known to be involved in carcinogenesis, and various su bstrates are now available to measure the activity of these enzymes. N o suitable serum tumour marker for head and neck squamous cell carcino ma (HNSCC) exists at this moment. Therefore, we compared proteinase-ac tivity in serum of 20 untreated HNSCC patients with that of 20 non-can cer individuals. When N-benzoyl-DL-arginine-beta-naphtylamide (BANA) w as used as the substrate, proteinase-activity seemed higher among pati ents, but this difference disappeared after adjustment for alcohol and tobacco consumption. Applying a-benzoyloxycarbonyl-L-arginyl-L-argini ne-7-amido- 4-methylcoumarine (ZAAM) as the substrate no difference wa s found. Addition of E-64, an inhibitor of cysteine proteinase showed that cathepsin B contributed minimally to the ZAAM-specific activity.