Other groups demonstrated upregulation of the HERV-W expression in neuroblastoma cell lines due to hypoxic conditions (Hu et al., 2016) or upregulation of the HERV-E expression in renal cell carcinomas due to inactivation of the von Hippel-Lindau factor and subsequent stabilization of the oxygen sensor protein HIF-1α (Cherkasova et al., 2011). Here, HIF1A is linked to neuroblastoma.