Pretreatment tumor prostaglandin E 2 concentration and cyclooxygenase-2 expression are not associated with the response of canine naturally occurring invasive urinary bladder cancer to cyclooxygenase inhibitor therapy

• Published in: Prostaglandins, leukotrienes and essential fatty acids Vol. 72; no. 3; pp. 181 - 186
• Main Authors: Mutsaers, A.J., Mohammed, S.I., DeNicola, D.B., Snyder, P.W., Glickman, N.W., Bennett, P.F., de Gortari, A.E., Bonney, P.L., Knapp, D.W.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2005
• ISSN: 0952-3278; 1532-2823
• DOI: 10.1016/j.plefa.2004.10.017

The purpose of this study was to determine the extent to which pretreatment prostaglandin E 2 (PGE 2) concentration and cyclooxygenase-2 (cox-2) expression could be used to predict the antitumor activity of cox inhibitor treatment in naturally occurring canine transitional cell carcinoma of the urinary bladder (TCC). Snap frozen tissues (to measure PGE 2) and formalin-fixed TCC samples (for cox-2 immunohistochemistry) were obtained by cystoscopy or surgery. Complete tumor staging was performed before and after one month of treatment with the cox inhibitor, piroxicam (0.3 mg/kg q24h po). The pretreatment PGE 2 concentration ranged from 57 to 1624 ng/g of TCC tissue; n = 18 dogs). Cox-2 immunoreactivity was observed in all TCC samples. There was no association between PGE 2 concentration, cox-2 expression, and change in tumor volume with piroxicam treatment. In conclusion, cox-2 expression or PGE2 concentration alone, or the combination of the two was not useful in predicting response to piroxicam treatment in canine TCC.