Identification of survivin, an inhibitor of apoptosis, in canine urinary bladder transitional cell carcinoma

Survivin, an inhibitor of apoptosis, is overexpressed in human invasive transitional cell carcinoma (TCC) of the urinary bladder. Survivin expression in canine TCC has not been defined. This study was designed to compare survivin expression between canine TCC and normal urinary bladder tissue. Reverse-transcriptase polymerase chain reaction (PCR) and immunohistochemistry (IHC) were performed on fresh-frozen and formalin-fixed tissues, respectively. All TCC tissues (n = 6) and 11/22 normal tissues assessed by PCR were positive for survivin. This difference was not significant (P = 0.06). With regard to IHC, 28/41 TCC samples were positive for nuclear survivin, whereas 0/46 normal tissues had nuclear immunoreactivity (P < 0.001). Cytoplasmic immunoreactivity did not significantly differ between TCC (7/41) and normal tissues (17/46) (P = 0.07). We conclude that nuclear survivin is present in canine TCC, but not in normal bladder urothelium. Future studies will evaluate the role of nuclear survivin in TCC development and as a potential therapeutic target.