MTOR and renal cell carcinoma: Previous literature has reported a close relationship between POSTN and TGFBI [19–22], We analyzed the correlation between TGFBI and POSTN at RNA, total protein, and phosphoprotein levels and found a positive correlation between the expression of the two (Fig. 4E), whereas previous studies have been performed on POSTN indicating the importance of the AKT/mTOR pathway in RCC [23].