Frontiers in Bioscience-Elite (FBE) is published by IMR Press from Volume 13 Issue 2 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
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Extensive industrial use of arylamines started in the middle of the 19th century in the dye industry. Because of the high incidence of bladder cancer, arylamines belong to the first and most intensively studied occupational and environmental carcinogens. In workers, biomonitoring of exposure to arylamines including ortho-toluidine started in the first half of the 20th century. This review highlights the many gaps in our knowledge on the human carcinogen ortho-toluidine.