Editing Brain tumor (section)

==Cause==
A known cause of brain cancers is [[ionizing radiation]].<ref name=nrsCT1/><ref name="nrsIR1">{{cite journal | last1=Smoll | first1=Nicolas R. | last2=Brady | first2=Zoe | last3=Scurrah | first3=Katrina | last4=Mathews | first4=John D. | title=Exposure to ionizing radiation and brain cancer incidence: The Life Span Study cohort | journal=Cancer Epidemiology | date=June 2016 | volume=42 | pages=60–65 | doi=10.1016/j.canep.2016.03.006 | pmid=27038588 }}</ref> Approximately 4% of brain cancers in the general population are caused by [[CT-scan]] radiation.<ref name="nrsCT1" /> For brain cancers that follow a CT scan at lags of 2 years or more, it has been estimated that 40% are attributable to CT-scan radiation.<ref name="nrsCT1" /> The risk of brain cancer is dose dependent, with the relative risk increasing by 0.8 for each 100 [[Gray (unit)|gray]] of ionizing radiation received. At this dose, approximately 6391 people would have to be exposed to cause 1 case of brain cancer.<ref name="nrsCT1" /> Ionizing radiation to the head as part of treatment for other cancers is also a risk factor for developing brain cancer.<ref name="Schaff 2023" />

Mutations and deletions of [[tumor suppressor gene]]s, such as [[P53]], are thought to be the cause of some forms of brain tumor.<ref>{{cite book | vauthors=Kleihues P, Ohgaki H, Eibl RH, Reichel MB, Mariani L, Gehring M, Petersen I, Höll T, von Deimling A, Wiestler OD, Schwab M | chapter = Type and frequency of p53 mutations in tumors of the nervous system and its coverings | title = Molecular Neuro-oncology and Its Impact on the Clinical Management of Brain Tumors | pages = 25–31 | year = 1994 | publisher = Springer | isbn=978-3-540-57351-7 | series=Recent results in cancer research | volume=135}}</ref> Inherited conditions, such as [[Von Hippel–Lindau disease]], [[tuberous sclerosis]], [[multiple endocrine neoplasia]], and [[Neurofibromatosis|neurofibromatosis type 2]] carry a high risk for the development of brain tumors.<ref name=PDQ2014MD/><ref name=HodgsonNielsen2016>{{cite journal | vauthors = Hodgson TS, Nielsen SM, Lesniak MS, Lukas RV | title = Neurological Management of Von Hippel-Lindau Disease | journal = The Neurologist | volume = 21 | issue = 5 | pages = 73–8 | date = September 2016 | pmid = 27564075 | doi = 10.1097/NRL.0000000000000085 | s2cid = 29232748 | type = Review }}</ref><ref name=RogersBarani2015>{{cite journal | vauthors = Rogers L, Barani I, Chamberlain M, Kaley TJ, McDermott M, Raizer J, Schiff D, Weber DC, Wen PY, Vogelbaum MA | title = Meningiomas: knowledge base, treatment outcomes, and uncertainties. A RANO review | journal = Journal of Neurosurgery | volume = 122 | issue = 1 | pages = 4–23 | date = January 2015 | pmid = 25343186 | pmc = 5062955 | doi = 10.3171/2014.7.JNS131644 | type = Review }}</ref> People with [[celiac disease]] have a slightly increased risk of developing brain tumors.<ref name=Hourigan2006>{{cite journal | vauthors = Hourigan CS | title = The molecular basis of coeliac disease | journal = Clinical and Experimental Medicine | volume = 6 | issue = 2 | pages = 53–9 | date = June 2006 | pmid = 16820991 | doi = 10.1007/s10238-006-0095-6 | s2cid = 12795861 | type = Review }}</ref> Smoking may increase the risk, but evidence of this remains unclear.<ref>{{cite web | title=Brain Cancer Causes, Symptoms, Stages & Life Expectancy | url=https://www.medicinenet.com/brain_cancer/article.htm#do_cell_phones_cause_brain_cancer | website=MedicineNet | access-date=24 February 2020 | language=en | quote = Other risk factors such as smoking, radiation exposure, and viral infection (HIV) have been suggested but not proven to cause brain cancer.}}</ref>

Although studies have not shown any link between [[Mobile phone radiation and health|cell-phone or mobile-phone radiation]] and the occurrence of brain tumors,<ref>{{cite journal | vauthors = Frei P, Poulsen AH, Johansen C, Olsen JH, Steding-Jessen M, Schüz J | title = Use of mobile phones and risk of brain tumours: update of Danish cohort study | journal = BMJ | volume = 343 | pages = d6387 | date = October 2011 | pmid = 22016439 | pmc = 3197791 | doi = 10.1136/bmj.d6387 }}</ref> the [[World Health Organization]] has classified mobile-phone radiation on the [[International Agency for Research on Cancer|IARC]] scale into [[List of IARC Group 2B carcinogens|Group 2B]] – possibly carcinogenic.<ref name="WHO_IARC_110531">{{cite press release |url= http://www.iarc.fr/en/media-centre/pr/2011/pdfs/pr208_E.pdf |title= IARC classifies radiofrequency electromagnetic fields as possibly carcinogenic to humans |work= [[World Health Organization]] press release N° 208 |publisher= [[International Agency for Research on Cancer]] |date= 31 May 2011 |access-date= 2 June 2011 |url-status= live |archive-url= https://web.archive.org/web/20110601063650/http://www.iarc.fr/en/media-centre/pr/2011/pdfs/pr208_E.pdf |archive-date= 1 June 2011 |df= dmy-all}}</ref>
The claim that cell-phone usage may cause brain cancer is likely based on epidemiological studies which observed a slight increase in [[glioma]] risk among heavy users of wireless phones. When those studies were conducted, GSM (2G) phones were in use. Modern, third-generation (3G) phones emit, on average, about 1% of the energy emitted by those GSM (2G) phones, and therefore the finding of an association between cell-phone usage and increased risk of brain cancer is not based upon current phone usage.<ref name=WCR2014CNS/>