TDK conference 2011

The aim of this study was to investigate immunohistochemical expression of cycloogygenase-2 (Cox-2) in canine mammary tumors of different histological types. Cox-2 enzyme expression was evaluated in 39 samples, 34 from mammary tumours, 5 from dogs with lymphoma. Among the breast tumors, there were 12% benign tumours, 48% carcinoma simplex, 8% adenocarcinoma, 12% tubulopapillary carcinoma and 12% other histological types.

Metastasis was observed in two cases among the patients with carcinoma simplex, and in a case with tubulopapillary carcinoma. In other cases, metatasis formation was not observed. We examined samples that resulted from recurrent tumors in two cases. These occured in patients with tubulopapillary carcinoma.

The tumours were surgically excised, and routine histopathological examination was performed. The extent of Cox-2 expression was detected by immunohistochemical analysis. We used monoclonal IgG1 (Rat Cox-2 aa. 368 to 604) antibody of mouse origin (BD Biosciences). The stainting was performed by the Vectastain Elite ABC kit (Vector Laboratories).

Cox-2 expression percentage was confirmed in benign tumours as an average of 3, in carcinoma simplex 37, in tubulopapillary carcinoma 77, in adenocarcinoma 15, in other histological types 45, and in lymphomas average 1.6.

Statistical analysis was taken after the summary of the data. Significant difference could be detected in carcinoma and tubulopapillary carcinoma (P=0.003063). The Cox-2 expression was higher in carcinomas than in benign tumours (P=0.007611). In addition, there were significant differences between the carcinomas and lymphomas (P=0.005718).

The study showed that the tendency to metastasis and recurrent disease is related to the level of Cox-2 expression. In addition, the malignant tumors had the highest values of Cox- 2 expression, from which we can conclude, that the malignancy is closely associated with levels of Cox-2. This finding suggests that Cox-2 inhibitor non-steroidal anti-inflammatory drugs (NSAID’s) may be helful in the treatment of carcinoma simplex and tubulopapillary carcinoma in addition to conventional anticancer therapies.