Editing Hypoxia (medicine) (section)

=====Tumor hypoxia=====
{{main|Tumor hypoxia}}
Tumor hypoxia is the situation where [[tumor]] cells have been deprived of oxygen. As a tumor grows, it rapidly outgrows its blood supply, leaving portions of the tumor with regions where the oxygen concentration is significantly lower than in healthy tissues. Hypoxic microenvironements in solid tumors are a result of available oxygen being consumed within 70 to 150 μm of tumour vasculature by rapidly proliferating tumor cells thus limiting the amount of oxygen available to diffuse further into the tumor tissue. The severity of hypoxia is related to tumor types and varies between different types. Research has shown that the level of oxygenation in hypoxic tumor tissues is poorer than normal tissues and it is reported somewhere between 1%–2% O2.<ref>Nejad, A.E. et al. (2021) The role of hypoxia in the tumor microenvironment and development of Cancer Stem Cell: A novel approach to developing treatment - cancer cell international, BioMed Central. Available at: https://cancerci.biomedcentral.com/articles/10.1186/s12935-020-01719-5#:~:text=Hypoxia%20is%20a%20common%20feature,blood%20vessels%20supplying%20the%20tumor (Accessed: 01 December 2023). </ref> In order to support continuous growth and proliferation in challenging hypoxic environments, cancer cells are found to alter their metabolism.  Furthermore, hypoxia is known to change cell behavior and is associated with extracellular matrix remodeling and increased migratory and metastatic behavior.<ref name="Gilkes et al 2014" /><ref name="Spill et al 2016" /> Tumour hypoxia is usually associated with highly malignant tumours, which frequently do not respond well to treatment.<ref name="Lumb 2017" />