CDK4 and neoplasm: Tumor suppressive miR-34 family members targets MYCN and inhibit the growth of NB cell lines In addition, other genes also targeted by miR-34a, including E2F3, BCL2, CCND1 and CDK4 were found to be involved in cell proliferation or apoptosis Over expression of miR-34a in NB cell lines induces cell cycle arrest decreases cell number and induces apoptosis. miR-34a significantly reduces tumor growth in anin vivo orthotopic murine model.