MTOR and renal cell carcinoma: 72 h TAC treatment modestly increased the p-mTOR/mTOR ratio in all investigated RCC cell lines (A498 [1.71 vs 0.61; p = 0.04], 786-O [1.63 vs 0.74; ns], ACHN [1.77 vs 0.61; ns]), indicating a slight increase in mTOR activity.