Abstract: Abstract Objective:To investigate the expression of Livin proteins and Smac proteins in the bladder transitional cell carcinoma (BTCC) and their correlation. Methods：The expression of Livin proteins and Smac proteins were assessed in 42 cases of the BTCC tissues and 18 cases of peritumorial normal mucosa tissue by SABC Immunohistochemistry,and their relationships with clinical pathological features were analyzed.Results:The expression of Livin proteins and Smac proteins in the BTCC were 73.8%(31/42) and 28.6%(12/42),while in 18 cases of peritumorial normal mucosa tissue,respectively, 0 and 77.8%(14/18).Significant differences of Livin proteins and Smac proteins expression were found between BTCC and peritumorial normal mucosa tissue groups(P＜0.01);and both were significantly correlated with recurrence(P＜0.05);but they didn’t correlate to sexualities, ages, histological grades, clinical stages, the number of tumors. And the expression levels of Livin proteins and Smac proteins showed a negative correlation in the BTCC (rs=-0.462, P＜0.05).Conclusion:The relatively high expression of Livin proteins and the low or not expression of Smac proteins may lead to the occurrence and recurrence of the BTCC, and both maybe play an important role in the cell apoptosis of the BTCC.

Key words: bladder transitional cell carcinoma (BTCC), Livin, Smac, apoptotic, Immunohistochemistry.