Salivary peroxidases have biological functions of particular importance to oral health. The aim of this paper is to shed the light on saliva and serum total peroxidases activity as well as the activity of each of salivary peroxidase (SPO) and myeloperoxidase (MPO) in patients with oral tumors. The studied participants were divided into two groups: the first group included 18 oral squamous cell carcinoma patients and 20 age and gender-matched healthy controls while the second group consisted of 20 oral ossifying fibroma patients and 23 age and gender-matched healthy controls. Total peroxidases activity was determined, and its specific activity was calculated in serum and whole mixed saliva as well as in the supernatant and pellet fractions of saliva. Furthermore, the activities of SPO and MPO were determined in each of saliva’s supernatants and saliva’s pellet fractions, and the thiocyanate (SCN-) concentration was measured in the supernatants fraction only. The results indicated the presence of a significant increase in the activity of both total peroxidase and MPO (p = 0.0001) in the salivary supernatants of oral squamous cell carcinoma patients relative to the control group. A significant increase (p = 0.0001) in total peroxidase activity in patients with oral ossifying fibroma was also found in serum compared with healthy individuals. In this study, we have shown that the measurement of total peroxidase and MPO activities in saliva may be used as an adjuvant tool for monitoring patients with oral malignancies
