ARNT and neuroblastoma: The induced transcription of HIF target genes in case of HIF-1β knockdown could be due to the remaining HIF-1β or compensation by HIF-2β subunits as has been reported for other NB cells.23 When mRNA levels measured in shHIF-1β or digoxin-treated cells were normalised to their counterpart WT untreated cells (Figures 6h and i), all genes promoting metastatic dissemination were significantly reduced both in vitro and in tumours, in line with the absence of invasion.