Editing Polychlorinated biphenyl (section)

===Cancer===
In 2013, the [[International Agency for Research on Cancer]] (IARC) classified dioxin-like PCBs as human [[carcinogen]]s.<!--"On the basis of sufficient evidence of carcinogenicity in humans and experimental animals, the Working Group classified PCBs as carcinogenic to humans (Group 1)"--><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 | display-authors = 3 | title = Carcinogenicity of polychlorinated biphenyls and polybrominated biphenyls | journal = The Lancet. Oncology | volume = 14 | issue = 4 | pages = 287–288 | date = April 2013 | pmid = 23499544 | doi = 10.1016/s1470-2045(13)70104-9 | url = https://hal.archives-ouvertes.fr/hal-01607039/file/lauby-secretan_lancet_2013_1.pdf }}</ref>
According to the U.S. EPA, PCBs have been shown to cause cancer in animals and evidence supports a cancer-causing effect in humans.<ref name="EPA" /> Per the EPA, studies have found increases in malignant melanoma and rare liver cancers in PCB workers.<!--"Studies of PCB workers found increases in rare liver cancers and malignant melanoma. The presence of cancer in the same target organ (liver) following exposures to PCBs both in animals and in humans and the finding of liver cancers and malignant melanomas across multiple human studies adds weight to the conclusion that PCBs are probable human carcinogens. --><ref name = "EPA"/>

In 2013, the IARC determined that the evidence for PCBs causing [[non-Hodgkin lymphoma]] is "limited" and "not consistent".<ref name="Lauby-Secretan"/> In contrast an association between elevated blood levels of PCBs and non-Hodgkin lymphoma had been previously accepted.<ref>{{cite journal | vauthors = Kramer S, Hikel SM, Adams K, Hinds D, Moon K |display-authors=3| 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 = 1067–1075 | date = August 2012 | pmid = 22552995 | pmc = 3440083 | doi = 10.1289/ehp.1104652 |bibcode=2012EnvHP.120.1067K}}</ref> PCBs may play a role in the development of cancers of the immune system because some tests of laboratory animals subjected to very high doses of PCBs have shown effects on the animals' immune system, and some studies of human populations have reported an association between environmental levels of PCBs and immune response.<ref name="EPA" />