The HIF-1α subunit is subjected to oxygen-dependent post-translational degradation by hydroxylation of prolyl residues within the oxygen-dependent degradation domain, which promotes the interaction of HIF-1α with the von Hippel–Lindau tumour-suppressor protein, a component of the protein–ubiquitin ligase complex that targets HIF-1α for rapid degradation. This evidence concerns the gene HIF1A and neoplasm.