title: Methyl tertiary-butyl ether mode of action for cancer endpoints in rodents.
abstract: There are no reports of studies that evaluate if methyl tertiary-butyl ether (MTBE) exposure causes cancer in humans. This evaluation of MTBE carcinogenicity is based on the results of animal studies. A weak tumorigenic response was reported for both MTBE and TBA in one tumor type (kidney) in male rats, for MTBE in one other tumor type (testicular) in male rats, for MTBE in one tumor type (liver) in female mice, and for TBA in one tumor type (thyroid) in female mice. The weight of the evidence does not support a genotoxic mode of action (MOA). Non-genotoxic MOAs have been demonstrated or suggested that correspond to the weak tumorigenic responses. These MOAs either do not occur in humans or humans are much less susceptible to these effects. It is, therefore, unlikely that humans would be exposed to sufficient levels of MTBE to cause these tumorigenic responses.
authors.affiliation: ToxWorks, Bridgeton, NJ, USA.
authors.forename: George
authors.initials: G
authors.lastname: Cruzan
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Borghoff
authors.forename: Ann
authors.initials: A
authors.lastname: de Peyster
authors.forename: Gordon C
authors.initials: GC
authors.lastname: Hard
authors.forename: Michael
authors.initials: M
authors.lastname: McClain
authors.forename: Douglas B
authors.initials: DB
authors.lastname: McGregor
authors.forename: Michael G
authors.initials: MG
authors.lastname: Thomas
mesh_terms: D000818:Animals; D015197:Carcinogenicity Tests; D002273:Carcinogens / Q000008:administration & dosage / Q000633:toxicity*; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D008297:Male; D008738:Methyl Ethers / Q000008:administration & dosage / Q000633:toxicity*; D051379:Mice; D009152:Mutagenicity Tests; D009369:Neoplasms / Q000139:chemically induced; D011237:Predictive Value of Tests; D051381:Rats; D012737:Sex Factors; D013045:Species Specificity
chemical_list: D002273:Carcinogens; D008738:Methyl Ethers; C043243:methyl tert-butyl ether