STC1 and renal cell carcinoma: Su et al. discovered that the knockdown of POLE2 in renal cell carcinoma causes the cell cycle to stop at the S phase and increase cell apoptosis via AKT/mTOR signaling 51, whereas Zhang et al. found that POLE2 knockdown attenuates cell proliferation and migration by reducing the expression of its downstream gene STC1 (Stanniocalcin 1) gene, which is a tumor promoter 52.