CDK4 and neoplasm: In view of these results, we assessed whether the sponging of miR-198 by circSP3 promoted tumor growth by de-repressing CDK4. Hep-3B cells were transfected with circSP3-overexpressing plasmids, NC plasmids, circSP3+CDK4-homo-520 (CDK4 knockdown) plasmids or circSP3+CDK4-homo-520-NC plasmids.