Objective:To investigate the clinicopathlogical significance of the CyclinE,p21WAF1/CIP1 and p53 expression in laryngeal carcinogenesis.Method:The expression of CyclinE,p21WAF1/CIP1 and p53 was examined by using immunohistochemical method in normal epithlia (20),dysplastic epithlia (40) and laryngeal cancers (60).Result:①In normal epithlium,dysplastic squamous epithlium and in squamous cell carcinoma of the larynx,the positive immunostaining rate of CyclinE protein was 5.0%(1/20),20.0%(8/40) and 45.0%(27/60) respectively (P＜0.001),and p21WAF1/CIP1 protein was 95.0%(19/20)，75.0%(30/40) and 63.3%(38/60) respectively (P＜0.01),while the rate of p53 was 0,30.0%(12/40) and 61.7%(37/60)(P＜0.001) respectively.②p21WAF1/CIP1 positive expression in highly、moderately and poorly differtiated carcinomas were 76.2%(16/21)、66.5%(19/29) and 30.0%(3/10) respectively (P＜0.05),p21WAF1/CIP1 protein expression was significantly associated with tumour cell differentiation.③The positive expression of CyclinE closely related with the positive expression of p53 (P＜0.05).No correlation was found between p21WAF1/CIP1 expression and p53 expression.Conclusion:①CyclinE and p53 could be an early molecular event in the carcinogenesis of larynx.②p21WAF1/CIP1 expression is associated with tumour cell differentiation.③The mutual mechenism of cell cycle regulators (CyclinE、p21WAF1/CIP1 and p53) play an important role in the laryngeal carcinoma.