To investigate the impact of inhibition of PI3K/Akt/mTOR axis pathway on the chemosensitivity of canine tumours, we evaluated the effects of the combination of the class I PI3K pathway inhibitors and Doxorubicin on the viability of canine SB and REM cells and utilized the Bliss additivism model to analyze the effects. This evidence concerns the gene MTOR and neoplasm.