NPY and neuroblastoma: [55]. It has been shown that ID2 is involved in normal neural crest development. Hypoxia induces ID2 expression and hypoxia-induced ID2 expression play a significant role in dedifferentiation of hypoxic neuroblastoma cell [56]. Intermittent hypoxia also caused a decrease in the expression of SNS neuronal lineage-specific marker genes, including NPY, Hash-1 and dHAND. Others have reported that neuroblastoma cells lost their neuronal/ neuroendocrine features and gained immature, neural crest-like phenotype upon exposure to hypoxia [38], [57].