title: Human health effects of tetrachloroethylene: key findings and scientific issues.
abstract: BACKGROUND
  The U.S. Environmental Protection Agency (EPA) completed a toxicological review of tetrachloroethylene (perchloroethylene, PCE) in February 2012 in support of the Integrated Risk Information System (IRIS).
  
  
  OBJECTIVE
  We reviewed key findings and scientific issues regarding the human health effects of PCE described in the U.S. EPA's Toxicological Review of Tetrachloroethylene (Perchloroethylene).
  
  
  METHODS
  The updated assessment of PCE synthesized and characterized a substantial database of epidemiological, experimental animal, and mechanistic studies. Key scientific issues were addressed through modeling of PCE toxicokinetics, synthesis of evidence from neurological studies, and analyses of toxicokinetic, mechanistic, and other factors (tumor latency, severity, and background rate) in interpreting experimental animal cancer findings. Considerations in evaluating epidemiological studies included the quality (e.g., specificity) of the exposure assessment methods and other essential design features, and the potential for alternative explanations for observed associations (e.g., bias or confounding).
  
  
  CONCLUSIONS
  Toxicokinetic modeling aided in characterizing the complex metabolism and multiple metabolites that contribute to PCE toxicity. The exposure assessment approach-a key evaluation factor for epidemiological studies of bladder cancer, non-Hodgkin lymphoma, and multiple myeloma-provided suggestive evidence of carcinogenicity. Bioassay data provided conclusive evidence of carcinogenicity in experimental animals. Neurotoxicity was identified as a sensitive noncancer health effect, occurring at low exposures: a conclusion supported by multiple studies. Evidence was integrated from human, experimental animal, and mechanistic data sets in assessing adverse health effects of PCE.
  
  
  CONCLUSIONS
  PCE is likely to be carcinogenic to humans. Neurotoxicity is a sensitive adverse health effect of PCE.
authors: National Center for Environmental Assessment.
authors: Kathryn Z
authors: KZ
authors: Guyton
authors: Karen A
authors: KA
authors: Hogan
authors: Cheryl Siegel
authors: CS
authors: Scott
authors: Glinda S
authors: GS
authors: Cooper
authors: Ambuja S
authors: AS
authors: Bale
authors: Leonid
authors: L
authors: Kopylev
authors: Stanley
authors: S
authors: Barone
authors: Susan L
authors: SL
authors: Makris
authors: Barbara
authors: B
authors: Glenn
authors: Ravi P
authors: RP
authors: Subramaniam
authors: Maureen R
authors: MR
authors: Gwinn
authors: Rebecca C
authors: RC
authors: Dzubow
authors: Weihsueh A
authors: WA
authors: Chiu
mesh_terms: D000818:Animals; D002274:Carcinogens, Environmental / Q000633:toxicity*; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000139:chemically induced; D009101:Multiple Myeloma / Q000139:chemically induced; D013750:Tetrachloroethylene / Q000633:toxicity*; D014481:United States; D014484:United States Environmental Protection Agency; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced
chemical_list: D002274:Carcinogens, Environmental; D013750:Tetrachloroethylene