CDKN1B and neuroblastoma: Our previous studies have shown that the ODC inhibitor DFMO depletes intracellular polyamine levels, induces p27Kip1 protein accumulation and G1 cell cycle arrest, downregulates MYCN protein, but also promotes cell survival by modulating the phosphorylation of Akt/PKB via the PI3K/Akt signaling pathway in MYCN-amplified NB cells (10,11).