HIF1A and neoplasm: In normal conditions, HIF-1α is continuously synthesized and hydroxylated through HIF prolyl-4-hydroxylases, leading to its rapid ubiquitination and proteasomal degradation (ubiquitin proteasome 26S), the von Hippel–Lindau (pVHL) function as a tumor suppressor binds to the ubiquitin ligase complex E3 targeting the HIF-1α subunit destruction in the O2 degradation domain, causing its short life.