Indeed, there was no apparent induction of HIF-1α pathways in IKKαKD A549 and H1299 tumor xenografts, even though IKKα knockdown also enhanced their tumor burdens (albeit to a lesser degree than observed for IKKαKD H1437 cells in which IKKα loss resulted in the up-regulation of HIF-1α protein levels and activity). Here, HIF1A is linked to neoplasm.