HIF1A expression in neuroblastomas has been positively correlated with tumor aggressiveness, probably to protect against the hypoxic conditions created by their rapid growth, and hypoxia has been shown to inhibit the differentiation of neuroblastoma cell lines grown in culture or as xenografts, and may induce neuroblastoma cells to acquire a stem cell-like phenotype [48]. Here, HIF1A is linked to neuroblastoma.