In adapting to hypoxic microenvironment, tumour cells activate a variety of signal pathways and derive a large number of regulatory factors, which promote tumour tolerance to hypoxia and the tumour’s ability to metastasise as well as reducing sensitivity to radiotherapy and chemotherapy.16,17 Hypoxia-inducible factor 1 (HIF-1) is a transcription factor activated by hypoxia. Here, HIF1A is linked to neoplasm.