Investigation Of The Differential Expression Of INOS In OSF, OLP, OLK And OSCC

Object: To investigate the different expression of inducible nitric oxide synthase(iNOS) among normal buccal mucous (NBM), oral submucous fibrosis(OSF), oral lichen planus(OLP), oral leukoplakia(OLK) and oral squamous cell carcinoma(OSCC), so as to evaluate the carcinogenic ability of OSF and discuss the role of iNOS in the carcinogenesis of OSF.Method: The expression of iNOS was examined by immunohistochemical SP method in 30 cases of OSF(comprises of 10 initial, 10 medium-term and 10 advanced stage cases), 15 cases of OLP, 15 cases of OLK, 15 cases of OSCC and 10 cases of NBM. The different positive cell rates and expression intensity of iNOS in the five groups were compared by statistics analysis.Results:1. NBM showed negative positive expression of iNOS. There were obvious expressions of iNOS in OSF, OLP, OLK and OSCC. Positive brown staining was mostly presented in plasm and membrane of basal and spinous cells.2. The differences of positive cell rates and expression intensity of iNOS between OSF, OLP, OLK, OSCC and NBM were statistically significant (P<0.05), but there were no significant differences between OSF and OLP, OSF and OLK.(P>0.05). There were no significant differences among the three stages in OSF(P>0.05). The difference of positive cell rates of iNOS between OSF and OSCC was no statistically significant (P<0.05), but the expression intensity of OSF is lower than that of OSCC, the difference is statistically significant(P<0.05).3. The carcinogenesis rates of OLP, OSF, OLK were related to the expression intensity of iNOS (P<0.05).Conclusion:1. The overexpression of iNOS in initial, medium-term and advanced stages of OSF possibly indicates the malignant potential of epithelia cells of three groups. There is possibly no correlation between malignant potential and the clinical pathological stage.2. The iNOS may involve in initiation and development of several oral precancerous lesions including OSF, and the malignant potential may have close relationship with the expression intensity of iNOS. The malignant potential order is OLP, OSF, OLK, the most intense expression of iNOS can be seen in OSCC.