HIF1A and neoplasm: HIF-1α is a subunit of HIF-1 that accumulates under hypoxic conditions and binds to HIF-1β to form a heterodimer that is transported into the nucleus and binds to hypoxia response elements in the genome, regulating the transcription and expression of a variety of downstream target genes, including the genes related to apoptosis, angiogenesis and tumor metastasis [13, 14].