Editing Malignancy (section)

===Photoradiation===
[[Hematoporphyrin|Hematoporphyrin derivative]] (HPD) is a drug which was developed to be absorbed by malignant cells and only becomes active when exposed to light.<ref>{{cite web | title = Hematoporphyrin derivative | work = NCI Dictionary of Cancer Terms. | date = 2021 | access-date = 23 April 2021 | url = https://www.cancer.gov/publications/dictionaries/cancer-terms/def/hematoporphyrin-derivative }}</ref> It is commonly used to identify and localise cancers as when it is under activation of blue light the red fluorescence of the malignant tumour (due to the HPD) can be observed easily.<ref name = "Dougherty_1978">{{cite journal | vauthors = Dougherty TJ, Kaufman JE, Goldfarb A, Weishaupt KR, Boyle D, Mittleman A | title = Photoradiation therapy for the treatment of malignant tumors. | journal = Cancer Research | date = August 1978 | volume = 38 | issue = 8 | pages = 2628–2635 | pmid = 667856 | url = https://cancerres.aacrjournals.org/content/38/8/2628.short }}</ref>

The combination of HPD with red light (photoradiation) has been used on various malignant tumours including malignant [[melanomas]] and [[carcinomas]] on a range of different organs including the breast and colon.<ref name = "Dougherty_1978" /> This form of treatment produces a [[singlet oxygen]] through the photodynamic process;<ref name = "Dougherty_1978" /> where the oxygen molecule exists in an electronically excited state.<ref>{{cite book | vauthors = Hrycay EG, Bandiera SM | title = Cytochrome P450 Function and Pharmacological Roles in Inflammation and Cancer | chapter = Involvement of Cytochrome P450 in Reactive Oxygen Species Formation and Cancer | series = Advances in Pharmacology | volume = 74 | pages = 35–84 | date = 2015 | pmid = 26233903 | doi = 10.1016/bs.apha.2015.03.003 | isbn = 9780128031193 | veditors = Hardwick JP }}</ref> The singlet oxygen is a cytotoxic agent <ref name = "Dougherty_1978" /> which holds the ability to eradicate malignant cells by preventing both [[nucleic acid]] and [[protein synthesis]].<ref>{{cite book | vauthors = Papadimitraki ED, Bertsias G, Chamilos G, Boumpas DT | chapter = Systemic Lupus Erythematosus | date = January 2011 | pages = 1083–1108 | publisher = Academic Press | doi = 10.1016/B978-0-12-374994-9.10058-0 | isbn = 9780123749949 }}</ref> The treatment process also utilises HPD's capability of accumulating at higher levels in malignant tissues compared to most other tissues.<ref name = "Dougherty_1978" />

In the case of deeply pigmented or larger tumours, a stronger course of this treatment process is required in order to be effective.<ref name = "Dougherty_1978" />