Transitional cell carcinoma (TCC) is the most common bladder cancer in dogs, and its prevalence is increasing. Most dogs are diagnosed late in the disease course and do not respond to therapy as well as dogs diagnosed earlier. A diagnostic screening test has low positive predictive value. MicroRNAs (miRNAs) have been used in human medicine as disease biomarkers and in determining prognosis. In mammals, miRNAs play a role in cell proliferation, differentiation, and apoptosis; in humans, they may be upregulated in cancerous cells.

One objective of this study was to determine expression of miRNAs in urinary bladder samples obtained from dogs. Diseased urinary bladder tissue samples were obtained from formalin-fixed paraffin-embedded archived samples; grossly normal bladder tissue samples were obtained from animals undergoing necropsy for reasons unrelated to the study. Included were tissues from 4 grossly normal bladders, 13 with nonneoplastic inflammatory bladder disease, and 18 with TCC. There was a significant difference in the expression of some miRNAs from all 3 groups. These results support the potential use for miRNAs as diagnostic biomarkers for identifying dogs with TCC.

Expression of microRNAs in urinary bladder samples obtained from dogs with grossly normal bladders, inflammatory bladder disease, or transitional cell carcinoma. Vinall RL, Kent MS, deVere White RW. AM J VET RES 73:1626-1633, 2012.