SPHK2 and neoplasm: Previous studies demonstrate that miR-577 is a well-recognized tumor suppressor and it negatively regulates a lot of oncogenes and oncogenic pathways, including Sphk2, Smurf1, Rab14, Rab25, LRP6, β-catenin, Wnt2b, and so on [12–14, 16–18, 30–32].