FKBP8 and breast cancer: disclosed that SPP could promote lung cancer and breast cancer progression by facilitating the degradation of FKBP8 to enhance mTOR signaling.[21] To confirm whether circSATB1 could regulate the metastasis of CRC cells via activating mTOR signaling through the proteasomal degradation of FKBP8, WB was performed to detect the activity of mTOR signals.