Editing Non-Hodgkin lymphoma (section)

==Causes==
Lymphomas are types of [[cancer]] that develop from [[lymphocyte]]s, a type of [[white blood cell]].<ref name="SEER2016">{{cite web |date=April 2016 |title=SEER Stat Fact Sheets: Non-Hodgkin Lymphoma |url=http://seer.cancer.gov/statfacts/html/nhl.html |url-status=live |archive-url=https://web.archive.org/web/20140706125600/http://www.seer.cancer.gov/statfacts/html/nhl.html |archive-date=6 July 2014 |access-date=13 August 2016 |website=NCI |df=dmy}}</ref> Risk factors include [[immunodeficiency|poor immune function]], [[autoimmune disease]]s, [[Helicobacter pylori infection|''Helicobacter pylori'' infection]], [[hepatitis C]], [[obesity]], and [[Epstein–Barr virus infection]].<ref name="NCI2016AdPt" /><ref name="WCR2014Cp2">{{cite book |title=World Cancer Report 2014 |date=2014 |publisher=World Health Organization |isbn=978-92-832-0429-9 |pages=Chapter 2.4, 2.6}}</ref> The [[World Health Organization]] <!-- (WHO) --> classifies lymphomas into five major groups, including one for Hodgkin lymphoma.<ref>{{cite web |date=1 June 2016 |title=Adult Non-Hodgkin Lymphoma Treatment (PDQ®)–Health Professional Version |url=http://www.cancer.gov/types/lymphoma/hp/adult-nhl-treatment-pdq#section/all |url-status=live |archive-url=https://web.archive.org/web/20160812081200/http://www.cancer.gov/types/lymphoma/hp/adult-nhl-treatment-pdq#section/all |archive-date=12 August 2016 |access-date=13 August 2016 |website=NCI |df=dmy}}</ref> Within the four groups for NHL are over 60 specific types of lymphoma.<ref>{{cite web |title=Different types of non Hodgkin lymphoma |url=http://www.cancerresearchuk.org/about-cancer/type/non-hodgkins-lymphoma/about/types/the-most-common-types-of-non-hodgkins-lymphoma |url-status=live |archive-url=https://web.archive.org/web/20160814034909/http://www.cancerresearchuk.org/about-cancer/type/non-hodgkins-lymphoma/about/types/the-most-common-types-of-non-hodgkins-lymphoma |archive-date=14 August 2016 |access-date=13 August 2016 |website=Cancer Research UK |df=dmy}}</ref><ref>{{cite book |last1=Bope |first1=Edward T. |url=https://books.google.com/books?id=_x_mCgAAQBAJ&pg=PT914 |title=Conn's Current Therapy 2016 |last2=Kellerman |first2=Rick D. |date=2015 |publisher=Elsevier Health Sciences |isbn=978-0-323-35535-3 |page=878 |language=en |archive-url=https://web.archive.org/web/20170910182735/https://books.google.com/books?id=_x_mCgAAQBAJ&pg=PT914 |archive-date=10 September 2017 |url-status=live |df=dmy}}</ref> Diagnosis is by [[bone marrow biopsy|examination of a bone marrow]] or [[lymph node biopsy]].<ref name="NCI2016AdPt" /> [[Medical imaging]] is done to help with [[cancer staging]].<ref name="NCI2016AdPt" />

The many different forms of lymphoma probably have different causes. These possible causes and associations with at least some forms of NHL include:
* Infectious agents:
** [[Epstein–Barr virus]]: associated with [[Burkitt's lymphoma]], [[follicular dendritic cell sarcoma]], [[extranodal NK-T-cell lymphoma]] and [[Epstein Barr virus positive diffuse large B-cell lymphoma, not otherwise specified|diffuse large B-cell lymphoma]].<ref name="Maeda2009">{{cite journal|vauthors=Maeda E, Akahane M, Kiryu S, Kato N, Yoshikawa T, Hayashi N, Aoki S, Minami M, Uozaki H, Fukayama M, Ohtomo K|title=Spectrum of Epstein-Barr virus-related diseases: A pictorial review|journal=Japanese Journal of Radiology|volume=27|issue=1|pages=4–19|year=2009|pmid=19373526|doi=10.1007/s11604-008-0291-2|s2cid=6970917}}</ref>
** [[Human T-cell leukemia virus]]: associated with [[adult T-cell lymphoma]].
** ''[[Helicobacter pylori]]'': associated with [[gastric lymphoma]].
** [[HHV-8]]: associated with [[primary effusion lymphoma]], [[Castleman disease#Multicentric|multicentric Castleman disease]].
** [[Hepatitis C virus]]: associated with [[splenic marginal zone lymphoma]], [[lymphoplasmacytic lymphoma]] and [[diffuse large B-cell lymphoma]].<ref name="Peveling-Oberhag">{{cite journal|vauthors=Peveling-Oberhag J, Arcaini L, Hansmann ML, Zeuzem S|title=Hepatitis C-associated B-cell non-Hodgkin lymphomas. Epidemiology, molecular signature and clinical management|journal=Journal of Hepatology|volume=59|issue=1|pages=169–177|year=2013|pmid=23542089|doi=10.1016/j.jhep.2013.03.018|doi-access=free}}</ref>
** [[HIV]] infection.<ref name="PinzoneFiorica2012" />
* Some chemicals, like [[polychlorinated biphenyls]] (PCBs),<ref name="Kramer">{{cite journal|vauthors=Kramer S, Hikel SM, Adams K, Hinds D, Moon K|title=Current Status of the Epidemiologic Evidence Linking Polychlorinated Biphenyls and Non-Hodgkin Lymphoma, and the Role of Immune Dysregulation|journal=Environmental Health Perspectives|volume=120|issue=8|pages=1067–75|year=2012|pmid=22552995|pmc=3440083|doi=10.1289/ehp.1104652|bibcode=2012EnvHP.120.1067K }}</ref><ref>{{cite journal|vauthors=Zani C, Toninelli G, Filisetti B, Donato F|title=Polychlorinated biphenyls and cancer: an epidemiological assessment|journal=J. Environ. Sci. Health C |volume=31|issue=2|pages=99–144|year=2013|pmid=23672403|doi=10.1080/10590501.2013.782174|bibcode=2013JESHC..31...99Z |s2cid=5294247}}</ref><ref name="Lauby-Secretan">{{cite journal|vauthors=Lauby-Secretan B, Loomis D, Grosse Y, El Ghissassi F, Bouvard V, Benbrahim-Tallaa L, Guha N, Baan R, Mattock H, Straif K|title=Carcinogenicity of polychlorinated biphenyls and polybrominated biphenyls|journal=Lancet Oncology|volume=14|issue=4|pages=287–288|year=2013|pmid=23499544|doi=10.1016/s1470-2045(13)70104-9|url=http://prodinra.inra.fr/ft/25BCE4BA-5EA4-4AA1-A446-23A01442B32E}}</ref> [[diphenylhydantoin]], [[Dioxins and dioxin-like compounds|dioxins]], and [[phenoxy herbicide]]s.
* Medical treatments, like [[radiation therapy]] and [[chemotherapy]].{{citation needed|date=August 2022}}
* Genetic diseases, like [[Klinefelter syndrome]], [[Chédiak–Higashi syndrome]], ataxia–telangiectasia syndrome.{{citation needed|date=August 2022}}
* Autoimmune diseases, like [[Sjögren syndrome]], [[celiac disease]], [[rheumatoid arthritis]], and [[systemic lupus erythematosus]].<ref name="Tobias2015">{{cite book|title=Cancer and its Management| vauthors = Tobias J, Hochhauser D |publisher=Wiley-Blackwell|year=2015|isbn=978-1-118-46871-5|edition=7th}}</ref><ref name=Freedman>{{cite book|veditors=Kufe DW, Pollock RE, Weichselbaum RR, ((Bast RC Jr)), Gansler TS, Holland JF, ((Frei E III))|title=Holland-Frei Cancer Medicine|author1=Arnold S Freedman|author2=Lee M Nadler|chapter=Chapter 130: Non–Hodgkin's Lymphomas|edition=5th|publisher=B.C. Decker|location=Hamilton, Ont|year=2000|isbn=1-55009-113-1|chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK20925/|url-status=live|archive-url=https://web.archive.org/web/20170910182735/https://www.ncbi.nlm.nih.gov/books/NBK20925/|archive-date=10 September 2017|df=dmy}}</ref>
* Bone trauma and microfractures associated with [[diffuse large B-cell lymphoma]] originating in [[bone marrow]].<ref>{{cite journal|last1=Subik|first1=M. Kristina|last2=Herr|first2=Megan|last3=Hutchison|first3=Robert E.|last4=Kelly|first4=Jennifer|last5=Tyler|first5=Wakenda|last6=Merzianu|first6=Mihai|last7=Burack|first7=W. Richard|date=November 2014|title=A Highly Curable Lymphoma Occurs Preferentially in the Proximal Tibia of Young Patients|journal=Modern Pathology |volume=27|issue=11|pages=1430–1437|doi=10.1038/modpathol.2014.51|issn=0893-3952|pmc=4201907|pmid=24743213}}</ref><ref>{{cite journal|last1=Stein|first1=M. E.|last2=Lewis|first2=D. C.|last3=Gershuny|first3=A. R.|last4=Quigley|first4=M. M.|last5=Zaidan|first5=J.|last6=Danieli|first6=N. Siegelmann|last7=Whelan|first7=J.|last8=Subramanian|first8=R.|date=April 2003|title=Trauma as an etiologic factor of primary bone lymphoma: a report of 4 cases|url=https://pubmed.ncbi.nlm.nih.gov/17472245/|journal=Journal of B.U.ON.|volume=8|issue=2|pages=163–166|issn=1107-0625|pmid=17472245}}</ref>
* Implants, made from hard metals or silicone, associated with [[Anaplastic large-cell lymphoma|anaplastic large cell lymphoma]].<ref>{{cite journal|last1=Palraj|first1=Bharath|last2=Paturi|first2=Anil|last3=Stone|first3=Ross G.|last4=Alvarez|first4=Harold|last5=Sebenik|first5=Matjaz|last6=Perez|first6=Maria T.|last7=Bush|first7=Larry M.|date=2010-11-01|title=Soft Tissue Anaplastic Large T-Cell Lymphoma Associated with a Metallic Orthopedic Implant: Case Report and Review of the Current Literature|url=https://www.jfas.org/article/S1067-2516(10)00326-1/abstract|journal=The Journal of Foot and Ankle Surgery|language=en|volume=49|issue=6|pages=561–564|doi=10.1053/j.jfas.2010.08.009|issn=1067-2516|pmid=20870426}}</ref><ref>{{cite journal|last1=Popplewell|first1=Leslie|last2=Chang|first2=Karen|last3=Olevsky|first3=Olga|last4=Nademanee|first4=A.|last5=Forman|first5=Stephen|date=2004-11-16|title=Primary Anaplastic Large Cell Lymphoma of the Breast Occurring in Patients with Silicone Breast Implants.|url=https://ashpublications.org/blood/article/104/11/4563/56021/Primary-Anaplastic-Large-Cell-Lymphoma-of-the|journal=Blood|language=en|volume=104|issue=11|pages=4563|doi=10.1182/blood.V104.11.4563.4563|issn=0006-4971}}</ref>

===Familial component===
Familial lymphoid cancer is rare. The familial risk of lymphoma is elevated for multiple lymphoma subtypes, suggesting a shared genetic cause. However, a family history of a specific subtype is most strongly associated with risk for that subtype, indicating that these genetic factors are subtype specific. [[Genome-wide association study|Genome-wide association studies]] <!-- (GWAS) --> have successfully identified 67 [[single-nucleotide polymorphism]]s <!-- (SNPs) --> from 41 [[Locus (genetics)|loci]], most of which are subtype specific.<ref>{{cite journal | vauthors = Cerhan JR, Slager SL | title = Familial predisposition and genetic risk factors for lymphoma | journal = Blood | volume = 126 | issue = 20 | pages = 2265–73 | date = November 2015 | pmid = 26405224 | pmc = 4643002 | doi = 10.1182/blood-2015-04-537498 }}</ref>

=== HIV/AIDS ===
The [[Centers for Disease Control and Prevention]] (CDC) included certain types of non-Hodgkin lymphoma as AIDS-defining cancers in 1987.<ref>{{cite journal | title = Revision of the CDC surveillance case definition for acquired immunodeficiency syndrome. Council of State and Territorial Epidemiologists; AIDS Program, Center for Infectious Diseases | journal = MMWR Supplements | volume = 36 | issue = 1 | pages = 1S–15S | date = August 1987 | pmid = 3039334 | url = https://www.cdc.gov/mmwr/pdf/other/mmsu3601.pdf | url-status = live | archive-url = https://web.archive.org/web/20170609012431/https://www.cdc.gov/mmwr/pdf/other/mmsu3601.pdf | df = dmy | archive-date = 9 June 2017 | author1 = Centers for Disease Control (CDC) }}</ref> Immune suppression rather than HIV itself is implicated in the pathogenesis of this malignancy, with a clear correlation between the degree of immune suppression and the risk of developing NHL. Additionally, other retroviruses, such as [[HTLV]], may be spread by the same mechanisms that spread [[HIV]], leading to an increased rate of co-infection.<ref>{{cite journal| vauthors = Lee B, Bower M, Newsom-Davis T, Nelson M |title=HIV-related lymphoma|journal=HIV Therapy|volume=4|issue=6|year=2010|pages=649–659|issn=1758-4310|doi=10.2217/hiv.10.54}}</ref> The natural history of HIV infection has greatly changed over time. As a consequence, rates of non-Hodgkin lymphoma (NHL) in people infected with HIV has significantly declined in recent years.<ref name="PinzoneFiorica2012">{{cite journal | vauthors = Pinzone MR, Fiorica F, Di Rosa M, Malaguarnera G, Malaguarnera L, Cacopardo B, Zanghì G, Nunnari G | title = Non-AIDS-defining cancers among HIV-infected people | journal = European Review for Medical and Pharmacological Sciences | volume = 16 | issue = 10 | pages = 1377–88 | date = October 2012 | pmid = 23104654 }}</ref>