Muscle-invasive transitional cell carcinoma of the urinary bladder is associated with down-regulated CPP32 expression and Bcl-2 positivity

Abstract

The objective was to get insight into the role of executive apoptotic enzyme caspase 3 (CPP32) and regulatory anti apoptotic protein Bcl-2 in the malignant pheno type of TCC. Samples were obtained from 84 TCC patients, who underwent transurethral resection, partial or radical cystectomy. Staging showed a superficial growth pattern in 41 patient, while other 43 showed invasive characteristics. Expression of CPP32 and Bcl-2 was determined by immunocytochemistry. Levels of expression were correlated with tumor stage and grade. Expression of CPP32 was positive in 80% of TCC patients. Low-, medium-and high positive status were observed in 18%, 24% and 38% of patients, respectively. There was a significant difference in the CPP32 expression between groups with superficial and invasive TCC tumors (p = 0.032), with frequency of CPP32 negative samples being higher and CPP32 high-positive samples being lower in patients with muscle-invasive tumors. Significant association was also found between CPP32 expression and tumor stage (p = 0.043). The positive rate of Bcl-2 protein expression was 48%. There was a statistically significant difference in the rate of Bcl-2 positivity between superficial and invasive TCC (p = 0.005), with frequency of Bcl-2 positive patients being higher in muscle-invasive TCC. Significant association was also found between Bcl-2 expression and both tumor grade (p=0.032) and stage (p=0.007). Muscle invasive TCC of the urinary bladder is associated with down-regulated expression of CPP32 and Bcl-2 positivity. Down-regulation of CPP32 and up-regulated Bcl-2 might, at least partially, play a role in the development of invasive characteristics of TCC.

Keywords

• cpp32
• bcl-2
• apoptosis
• tcc
• urinary bladder