Serum dipeptidyl peptidase (DPP) IV activities in oral cancer patients.

Dipeptidyl peptidase (DPP) IV activities in normal human sera and in the sera of patients with malignant tumors of the oral region were assayed. Patients with oral squamous cell carcinoma had significantly lower enzyme activity than that of normal controls (p less than 0.001). Patients with advanced carcinoma showed a more significant reduction of serum enzyme activity. On the other hand, in oral squamous cell carcinoma patients with hepatic dysfunction, the serum enzyme activity was significantly increased (p less than 0.02).