Use of a medium-term liver focus bioassay to assess the hepatocarcinogenicity of 1,2,4,5-tetrachlorobenzene and 1,4-dichlorobenzene.
1,2,4,5-Tetrachlorobenzene (TeCB) and 1,4-dichlorobenzene (DCB) are important environmental contaminants that have been used extensively for a variety of industrial applications. Limited data are available in the literature regarding the carcinogenicity of TeCB. DCB has been shown to cause renal adenocarcinomas in rats and hepatic adenomas and carcinomas in mice at high doses in a 2-year study. In the studies presented here, we report that TeCB can promote the formation of preneoplastic foci and DCB cannot in a medium-term initiation/promotion assay. These results suggest that TeCB is a liver tumor promoter and that DCB is not at fairly low doses (0.1 and 0.4 mmol/kg per day).
Gustafson
D L
DL
Department of Environmental Health, Center for Environmental Toxicology & Technology, Colorado State University, Fort Collins 80523-1680, USA. dangus@cvmbs.colostate.edu
Coulson
A L
AL
Feng
L
L
Pott
W A
WA
Thomas
R S
RS
Chubb
L S
LS
Saghir
S A
SA
Benjamin
S A
SA
Yang
R S
RS
D000818:Animals; D001835:Body Weight; D002273:Carcinogens / Q000633:toxicity*; D002722:Chlorobenzenes / Q000633:toxicity*; D005982:Glutathione Transferase / Q000378:metabolism; D008099:Liver / Q000201:enzymology / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced* / Q000201:enzymology / Q000473:pathology; D008297:Male; D009929:Organ Size; D011230:Precancerous Conditions / Q000139:chemically induced / Q000201:enzymology / Q000473:pathology; D051381:Rats; D011916:Rats, Inbred F344
D002273:Carcinogens; D002722:Chlorobenzenes; C018673:1,2,4,5-tetrachlorobenzene; C018511:4-dichlorobenzene; D005982:Glutathione Transferase