Objective To study the expression and its relationship of murine double minute 2（MDM2）, P53 protein in oral leukoplakia and squamous cell carcinoma. Methods Immunohistochemical assay was used to detect the expression of MDM2 and P53 proteins in 15 normal oral epithelium tissues, 24 cases of oral leukoplakias and 41 cases of oral squamous cell carcinomas. Results There were no positive expression of MDM2 and P53 in normal mucosa. With significantly difference compared with the normal group（P0.05）, while P53-positive rate was significant difference（P
