HIF1A and cancer: Hypoxia is a characteristic of invasive cancers that can lead to the development of an aggressive phenotype through a mechanism mediated mainly by HIF-1α, which includes cell immortalisation and dedifferentiation, pH regulation, autocrine growth/survival, angiogenesis, invasion/metastasis, and resistance to chemotherapy (Semenza, 2006, 2009; Grothey and Galanis, 2009).