MTOR and renal cell carcinoma: Different approaches (WB, IF, and IHC) to identify molecules related to mTOR activity such as mTOR, p-mTOR, and its targets, p-p70S6K, p-S6Rb, and p-4E-BP1 were compared in renal cell carcinoma biopsies using different approaches in order to find the best strategy to identify mTORC1 active tumors.