We explored the role of PP2A-B55δ both in regulating the cell cycle, migration, colony formation, apoptosis, and proliferation of human hepatoblastoma HepG2 cells and in tumor growth in xenograft mice in the presence of cDDP, and we investigated the details of the microRNA-133b (miR-133b)/PPP2R2D signaling pathway. This evidence concerns the gene PPP2R2D and neoplasm.