Expression of cyclooxygenase-2 in neoplasms of the mammary gland in bitches

The aim of the study was to investigate the cyclooxygenase-2 expression in correlation with other neoplasm traits such as: histological type, the differentiation grade, proliferative activity, estrogenic receptor, as well as Hsp70 and p53 proteins expression. Material for the investigation comprised mammary gland tumours, collected from dogs, the patients of veterinary clinics, during surgical procedures. All together 14 adenomas, 66 complex carcinomas, 47 simple carcinomas and 6 solid carcinomas were studied. Evaluations were conducted with histopathological and immunohistochemical methods using suitable antibodies. Expression of COX-2 was observed in 95% of cancers, in case of which, the complex cancers constituted the highest percentage (48.4%). The highest expression of COX-2 was revealed in simple and complex cancers and in cancers with the 3rd degree of histological malignancy. The significant correlation between expression of COX-2 and high mean value of the mitotic index was found. The high expression of COX-2 was also correlated with the expression of protein p53 and expression of the protein Hsp 70. Obtained results suggest that cyclooxygenase-2 may be a prognostic factor, but it requires detailed clinical confirmation.