HIF1A and cancer: As a subunit of the heterodimeric transcription factor hypoxia-inducible factor 1 (HIF1), HIF-1α is a key transcription factor in hypoxia that contributes to the regulation of energy metabolism, the maintenance of hematopoietic stem cells, angiogenesis, proliferation, apoptosis, invasion, and metastasis of cancer cells [8–11].