Abstract: Objective:To investigate the possible relationship betwween P16 PCNA expression and their significance in human esophageal squamous cell carcinoma Methods:84 resected esophageal carcinomas speciments was examined for the expression of P16 PCNA proteins by using immunohistochemical S P method Results:The expression of P16 gene was 54 8%.The lower the differentiation of esophageal carcinoma,the lower the P16 positive rate ( P 0 01).The positive rate was significantly related to the ability of node metastasis TNM staging and postoperative ( P 0 05).The PCNA positive cell rates of esophageal cancer were 12 9%、26 9%、and 47 5% in well、moderately and poorly differentiated carcinoma respectively and showed a significant negative correlation with survival the differentiation degree of the tumor and the ability of node metastasis( P 0 001). Conclusion :the results suggest expression of P16 in esophageal carcinoma play an important role in suppression of invasive growth and metastasis P16 and PCNA may serve as a marker of predicting metastasis and prognosis of esophageal carcinoma.