Histological and Immunohistochemical Evaluation of Phosphorylated Mechanistic Target of Rapamycin in Canine Skin Tumours.

Abstract

The mechanistic target of rapamycin (mTOR) plays an important role in cellular functions, including growth and metabolism. Recently, mTOR and the activated phosphorylated form of mTOR (p-mTOR) have been reported as potential prognostic markers in many human tumours. However, there are few studies on its activation in canine tumours. We investigated the expression of p-mTOR in 17 canine skin tumours (CSTs), of which 58.8% were epithelial and melanocytic and 41.2% were mesenchymal tumours. Seventy-six per cent of the CSTs had high or moderate expression of p-mTOR. Mean p-mTOR expression in the epithelial and melanocytic tumours (5.7&#xa0;&#xb1;&#xa0;0.56) was significantly higher (P&#xa0;<0.05) than that of the mesenchymal tumours (3.14&#xa0;&#xb1;&#xa0;0.55). The age of the animals had no influence on p-mTOR expression. These findings suggest that activation of m-TOR is important in the development of skin tumours in dogs and the study might form the basis for further research on utilizing m-TOR inhibitors as improved therapeutic modalities in canine skin tumours.