HIF1A and neoplasm: In colon cancer, the interaction of the levels of interleukin-6 (IL-6) and the increase of hypoxia-inducible factor (HIF)1α favours the expression of the pro-angiogenic VEGF isoform, which contributes to tumour proliferation, the escape from apoptosis and the migration of the tumour cells, to which is added its affinity with the stage of the tumour [155].