A related immunosuppressant, mycophenolic acid, a potent inosine monophosphate dehydrogenase (IMPDH) inhibitor, was shown to induce senescence in imatinib-resistant chronic myelogenous leukemia cells [86], while hydroxyurea induced senescence in MYCN-amplified neuroblastoma cells [87]. This evidence concerns the gene MYCN and neuroblastoma.