Objective To evaluate the changes of the activity of HAase in saliva of oral squamous cell carcinoma（OSCC） patients. Methods HAase levels present in saliva of normal cases, OSCC patients and benign individuals were measured using ELISA -like assay. Results The means of HAase levels in saliva of OSCC
patients were 2 to 3-fold elevated when compared to those of the normal cases and the benign individuals. And there was no significant difference between the benign tumors individuals and those of normal cases（P>0.05）. The cut-off level of HAase activity was defined as 5.0 U/L, and the HAase tests were showed 79.17% sensitivity, 65.00% specificity to detect OSCC patients. The HAase levels in saliva positively correlated with the TNM stages pathological grades and nodal metastasis of OSCC, not correlated with the pathological grades of OSCC（P>0.05）. Conclusion HAase plays an important role in the growth and metastasis of OSCC，and HAase in saliva can not be independently used in diagnosis of OSCC.
