Purpose: The aim of our study was to determine the concentration of serum MMP-9 in healthy participants and in patients with salivary gland tumor. 

  Materials and Method: Using an ELISA kit, the circulating levels of MMP-9 in sera from 58 patients with salivary gland tumor (31 pleomorphic adenoma, 17 adenoid cystic carcinoma and 10 mucoepidermoid carcinoma) and 30 healthy controls was assessed.

Results: The serum MMP9 level in patients with salivary gland tumors (380.0±301.3 pg/ml) also patients with benign tumors (354.3±218.7 pg/ml) (354.3±218.7 pg/ml) were significantly lower than that in the healthy group (727.4±624.6 pg/ml) (Respectively p= 0.02 and p= 0.01). Mean serum MMP9 concentration in malignant tumors was (402.3±441.8pg/ml) higher than benign tumors (354.3±218.7 pg/ml) but the difference was not significant (p= 0.9). 

  Conclusion: Our results showed that serum level of MMP9 decreased in patients with salivary gland tumors which suggest that MMP9 may not have a potential role in development and pathogenesis of salivary gland tumor.