Objective To investigate the expression of a dismtegnn and metalloproteinase-12 (ADAM12) and proliferating cell nuclear antigen (PCNA) in human bladder carcinoma,and to explore their correlation with different grades and stages of bladder cancer.Methods Biopsies of 12 normal bladder and 43 bladder tumors were performed.And immunohistochemistry was conducted to detect the expression of ADAM12 and PCNA in the biopsies.Results Positive expression signals of ADAM12 were detected significantly higher inthe bladder cancer biopsies than that in the normal ones (Z =4.879,P ＜ 0.05),and the expression level of ADAM-12 in lower histological grade was significantly higher than that in the moderate and higher histological grades (x2 =22.3685,P ＜ 0.01).Positive expression signals of PCNA were detected significantly higher in the bladder cancer biopsies than that in the normal ones (Z =4.879,P ＜ 0.05)).Those with lower histological grade had a higher expression level of PCNA when compared with the moderate and higher histological grades (x2 =10.665,P =0.0137).The expression of ADAM-12 was positively correlated with PCNA in bladder cancer (r =1.000,P ＜ 0.0001).Conclusion The over expression of ADAM12 and PCNA maybe play an important role in development of the bladder tumors.And ADAM12 may be a promising biomarker of bladder cancer in the clinical behavior.