Hypoxia-inducible factor 1 (HIF1) is a heterodimer, which contains a HIF1α regulatory subunit and a HIF1β constitutive subunit, that plays a critical role in facilitating the transcription of a panel of genes related to tumor proliferation, metastasis, angiogenesis, and glycolysis, such as lactate dehydrogenase A (LDHA), phosphoglycerate kinase 1 (PGK1), and monocarboxylate transporter 4 (MCT4) [74,75,76]. The gene discussed is ARNT; the disease is neoplasm.