R. Baan, Y. Grosse, K. Straif
Dec 1, 2009
Citations
21
Influential Citations
761
Citations
Quality indicators
Journal
The Lancet. Oncology
Abstract
In October, 2009, 23 scientists from six countries met at the International Agency for Research on Cancer (IARC) to reassess the carcinogenicity of several chemical and occupational exposure circumstances previously classifi ed as ”carcinogenic to humans” (Group 1) and to identify additional tumour sites and mechanisms of carcinogenesis (table). These assessments will be published as the sixth and last part of Volume 100 of the IARC Monographs. Four aromatic amines and two related industrial processes were reaffi rmed as Group-1 carcinogens based on suffi cient evidence that they cause urinary bladder cancer in humans. The Group-1 classifi cation of dyes metabolised to benzidine and of 4,4’-methylenebis(2-chloroaniline) was based on suffi cient evidence in animal models and strong mechanistic evidence. Exposure to polycyclic aromatic hydro carbons (PAHs) causes cancers of the skin and lung in humans. Various PAH-related industries and PAHcontaining complex mixtures were confi rmed as Group-1 carcinogens. Although there are no epidemiological studies of benzo[a]pyrene, carcinogenicity in many animal species and strong mechanistic evidence justifi ed its classifi cation in Group 1. The carcinogenicity to humans of other chemicals and exposure scenarios was reaffi rmed (table). For ethylene oxide, the epidemiological evidence was limited, but there is suffi cient evidence for its carcinogenicity in rodents. Additionally, ethylene oxide is genotoxic and mutagenic in many in-vitro tests and in-vivo studies in animals, and its cytogenetic eff ects in lymphocytes of exposed workers provided strong support for its classifi cation in Group 1. Workers in the rubber-manufacturing industry have an increased risk for leukaemia, lymphoma, and cancers of the urinary bladder, lung, and stomach. Due to the diversity and com plexity of the exposures in this industry, it is diffi cult to identify causative agents, but there is strong evidence of genotoxic eff ects in these workers. The Working Group reviewed more than 100 epidemiological studies of benzene and confi rmed its carcinogenicity, with suffi cient evidence for ANLL, and limited evidence for ALL, CLL, MM, and NHL (for abbreviations, see table footnote). The Working Group also found limited evidence of an association between maternal exposure to painting—before and during pregnancy—and an increased risk of childhood leukaemia in the off spring. Dioxin (2,3,7,8-tetrachlorodibenzopara-dioxin, TCDD) was classifi ed in Group 1 in 1997, based on limited evidence of carcinogenicity in humans, For more on the IARC Monographs see http:// monographs.iarc.fr