The evidence for increased risk of non-Hodgkin lymphoma in exposed workers is "suggestive" for the following agents: non-arsenical insecticides, TCDD, tetrachloroethylene, and trichloroethylene. The evidence is also suggestive for hairdressers and barbers. [Siemiatycki, p. 334] "Patients who have received immunosuppressive therapy and/or organ transplants are at increased risk for non-Hodgkin's lymphoma, suggesting that there may be a combination of chemical immunosuppression and viral infection resulting in lymphomas in some individuals." [APHA, p. 331] "Our results support previously reported increased risks among farmers, printers, medical professionals, electronic workers, and leather workers." [
PMID 18805886] "The Working Group concluded that there is sufficient evidence of excess malignant lymphoma among rubber workers." [IARC 2012: Occupational Exposures in the Rubber-Manufacturing Industry] "Studies from the styrene-butadiene industry show an excess of leukaemia, and a dose-response relationship with cumulative exposure to butadiene, while studies from the monomer industry show an excess of haematolymphatic malignancies in general, attributable both to leukaemia and malignant lymphoma." [IARC 2012: 1,3-Butadiene] Data on the carcinogenicity of butadiene in humans derive essentially from studies conducted among workers employed in the production of the monomer and in the production of styrene-butadiene rubber (SBR), where high exposure levels occurred in the past." [Siemiatycki, p. 338]