Cox-2 expression after chemotherapy in a canine nasal transitional cell carcinoma: a case report

An eight year-old mixed breed dog was referred for evaluation with chronic sneezing, epistaxis and nasal bone deformation. A clinical exam revealed a deformity of the left nasal bone. Cytological evaluation of the nasal cavity showed round and cuboid cells in different stages of maturation. Computed tomography images identified a diffuse soft tissue mass in the nasal cavity. The histopathological diagnosis was transitional cell carcinoma. Chemotherapy with cisplatin and piroxicam was initiated. Computed tomography was used to follow the chemotherapy outcome. As many nasal carcinomas express COX-2, its expression was evaluated before and after chemotherapy. Computed tomography revealed a significant reduction of the tumour mass. Inmunohistochemistry showed a marked decrease in COX-2 expression and after 1120 days, the dog remained without clinical signs. Thus, the use of piroxicam and cisplatin is revealed to be effective in the treatment of a nasal transitional carcinoma in a dog. Also, it is possible to postulate that a decrease in COX-2 expression after chemotherapy may be regarded as an indication for a good response to the treatment and favourable outcome. To the authors’ knowledge this is the first report that evaluates COX-2 expression after chemotherapy.