USE OF THE SYRIAN-HAMSTER EMBRYO CELL-TRANSFORMATION ASSAY FOR DETERMINING THE CARCINOGENIC POTENTIAL OF HEAVY-METAL COMPOUNDS

Cobalt sulfate hydrate, gallium arsenide, molybdenum trioxide, vanadiu m pentoxide, and nickel sulfate heptahydrate were tested in the Syrian hamster embryo (SHE) assay in order to increase the SHE assay databas e for heavy metals. All five compounds produced significant morphologi cal transformation at one or more doses in a dose-responsive manner. C obalt sulfate hydrate, gallium arsenide, molybdenum trioxide, and nick el (II) sulfate heptahydrate were all positive with a 24-hr exposure, suggesting direct DNA perturbation. Vanadium pentoxide was negative wi th a 24-hr exposure, but positive with a 7-day exposure. This pattern of response (24-hr SHE negative/7-day SHE positive) has been seen with other chemicals which have tumor promotion-like characteristics. Sinc e the inception of the use of the SHE cell transformation assay for de tecting the neoplastic transformation potential of chemicals, over 42 heavy metal compounds have been tested in this assay. Based on the 24 metal compounds which have been tested in the SHE, Salmonella, and som e type of rodent bioassay, the SHE assay is 92% concordant with rodent bioassay carcinogenicity results, including a sensitivity of 95% (21/ 22) and a specificity of 50% (1/2). At this time, the measure of SHE a ssay specificity for rodent carcinogenicity of metals is limited by th e paucity of metal compounds which are rodent noncarcinogens. The Salm onella assay results are only 33% concordant with the rodent bioassay for these same chemicals. This relatively high concordance between the SHE assay and the rodent bioassay carcinogenicity results demonstrate s the utility of the SHE assay for determining the carcinogenic potent ial of heavy metal compounds in rodent cancer bioassays. (C) 1996 Soci ety of Toxicology.