HIF-1α has been identified as one of the key regulators in tumour progression, cancer cell proliferation, invasion and angiogenesis [46,47] by the activation of the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathways [48]. Here, MTOR is linked to cancer.