Study On The Expression Of MDM2 And P21^WAF/CIP1 In Oral Submucous Fibrosis And OSF Concomitant With OSCC

Objective:To investigate the expression of MDM2 and p21^WAF/CIP1protein in oral submucous fibrosis(OSF)and oral submucous fibrosis concomitant with oral squamous cell carcinoma(OSCC),and to evaluate their possible roles in carcinogenesis of OSF.Method:MDM2 and p21^WAF/CIP1protein expressions were assessed in 44 cases of OSF,15 cases of OSF concomitant with OSCC and 8 cases of normal control tissues via SP immunohistochemistry with the MDM2 and p21^WAF/CIP1rat anti-human monoclonal antibody.Statistic analysis was performed to figure out their expressions or correlation among their expressions and clinicopathological parameters of the patients with OSF concomitant with OSCC.Results:Positive MDM2-immunoreactivities were seen in early,middle,late stage OSF and OSF concomitant with OSCC,but negative in normal contol group.Positive p21^WAF/CIP1-immunoreactivities were seen in normal contol tissues and OSF,however.The expression of MDM2 increased(P＜0.01),while the expression of p21^WAF/CIP1decreased(P＜0.01)in OSF concomitant with OSCC compared with those in normal control tissues.The expression of MDM2 in OSF concomitant with OSCC tissues was significantly higher than that in OSF and normal oral tissues(P＜0.01).The expression of MDM2 at middle and late stages increased when compared with early stage(P＜0.01). There was no significantly difference between middle and late stage of OSF.The expression of p21^WAF/CIP1in OSF concomitant with OSCC tissues was significantly lower than that in the early and middle stages of OSF tissues(P＜0.01).The expression of p21^WAF/CIP1in OSF concomitant with OSCC tissues was significantly lower than that in the late stage of OSF tissues(P＜0.05).There was a statistic inverse correlation between MDM2 and p21^WAF/CIP1expressions in OSF and OSF concomitant with OSCC tissues(r=-0.763,P＜0.01).Conclusion:The frequency of MDM2 protein positive expression in OSF concomitant with OSCC was obviously higher than thant in OSF tissues. It may act as an important role in carcinogenesis of OSF.The cyclin-dependent kinase inhibitor p21^WAF/CIP1protein positive expression was obviously lower in OSF concomitant with OSCC than in OSF.There was a statistic inverse correlation between MDM2 and p21^WAF/CIP1 expressions in OSF and OSF concomitant with OSCC tissues.MDM2 could decrease the expression of p21^WAF/CIP1protein in OSF concomitant with OSCC.This study supports the hypothesis that they may contribute to the carcinogenesis of OSF.