Mutation Research, 266 (1992) 43-60
43
© 1992 Elsevier Science Publishers B.V. All fights reserved 0027-5107/92/$05.00
MUTREV 07313
IHTERNATIONAL COHHISSIO~ FOR PROTECTION AGAINST ENVIRONHENTAL HUTAGENS AND CARCINOGENS
A method for comparing and combining short-term genotoxicity test data: Results and interpretation M.L. M e n d e l s o h n a, D . H . M o o r e II a a n d P . H . M . L o h m a n b a Biomedical Sciences, Lawrence Livermore National Laboratory, P.O. Box 5507, Livermore, CA 94550 (U.S.A.) and b MGC - - Laboratory of Radiation Genetics and Chemical Mutagenesis, University of Leiden (The Netherlands)
(Received 9 September 1991) (Accepted 7 October 1991)
Keywords: Short-term genotoxicity test data, comparing and combining; Test data, genotoxicity; Composite scoring system
In the previous papers in this series, we describe a general approach toward creating a composite scoring system for genotoxicity testing. The method combines dose, metabolic activation and sign of outcome information in a way that accommodates negative and positive outcomes. It organizes the data hierarchically into replicates within a given test, tests within a class, classes within families, and finally families within a single agent score for each chemical (Lohman et al., 1992). We developed an optimized method to use close information in such a system (Moore et al., 1992), and we applied the method to a sizable dataset prepared by Waters et al. (1988) for the International Agency for Research on Cancer (IARC). This paper summarizes and tries to interpret the overall behavior of the system, including the relationships among its components, its statistical properties, our understanding of its mechanisms, its potential for future development, and what it
Correspondence: Dr. M.L. Mendelsohn, Biomedical Sciences, Lawrence Livermore National Laboratory, P.O. Box 5507, Livermore, CA 94550 (U.S.A.).
might be telling us about environmental mutagenicity testing. Detailed chemical results will be presented in later papers, as will the relationship of the present data to the corresponding system that has been developed for carcinogenesis (Nesnow, 1990). The experience to be described is limited to using the system to estimate general genotoxicity; the system has yet to be adapted or applied to other targets such as genotoxicity in the contexts of carcinogenicity or heritable mutation. The database
The database presently contains 113 chemicals which meet the minimal criteria of 3 conventional tests in vitro and 2 conventional tests in vivo. it includes 85 tests which meet the minimal criterion of at least 5 cltcmicals per test. Detail on the data is given in ~'~e two previous papers. For present purposes ~t is important to know that collection and am~otation of the material was done by expert committees in the context of the IARC process of reviewing chemicals for their poten,~i~O carcinogenicity. The data thus come
44 TABLE 1 C H E M I C A L S O R D E R E D BY A G E N T S C O R E W I T H R E L A T E D S T A T I S T I C S Chemical
N u m b e r of classes tested
Agent score
Standard deviation
95% lower limit
95% upper limit
Ethanol Melamine Chlorodifluoromethane C.I. acid red 14 Pentachloronitrobenzene
16 5 7 6 6
-27.7 - 26.4 -26.1 - 23.3 - 20.5
15.1 4.3 16.4 6.1 7.4
-35.7 - 31.7 -41.2 - 29.7 - 28.2
-
Saccharin Halothane Isoniazid Phenylbutazone Caprolactam
11 9 1! 7 l0
-
18.8 18.7 18.6 18.4 18.2
14.0 25.2 10.3 5.8 12.6
-28.2 -38.0 -25.5 -23.8 - 27.2
-9.4 0,7 - 11,7 - 13,0 - 9,2
Diethylhexylphthalate Polychlorinated biphenyls Ethylenethioarea Saccharin, sodium Methoxychlor
15 8 14 15 7
-
17.4 16.9 16.8 15.8 15.7
15.1 12.1 14.0 16.4 15.2
- 25.7 -27.0 - 24.9 -24.8 -29.8
- 9,0 -6.8 - 8.7 -6.7 - 1.7
Polybrominated biphenyls Chloroform Chloramphenicol Metronidazole Maleie hydrazide
6 13 8 i2 9
15.5 15.3 - 15.1 - 14,8 - 14,1
5.5 9.6 14.8 14.1 16.3
- 21.3 -21.1 -27.5 - 23.7 -26.7
- 14,1 - 13,9 - 13,5 - 13,2 - 12,8
10.2 23.6 7.6 9.9 18,0
-21.4 - 29.7 - 20,5 - 18.7 -27.9
12,4 12,1 11.9 I 1.3 10.7
6,9 8.8 20.3 20.9 20.1
-21.0 -20.3 - 33.2 - 26.3 - 23.4
-3.9 9.4 3.7 2.1
-9,7 -8.9
8.6 10.5
- 8,7
14.0
-8.6 - 8,4
15.0 ! 5.0
- 15.2 - 16.0 - 17.6 -21.1 - 20.9
-4.3 - 1.8 0.2 4.0 4. I
- 12.4
- 1.9
Trichloroethane, 1,1.1-
I0
Dichlor~melhane
II 7 15
Tetrachloroethylene Phenobarbital
Endrin
8
Mestranol Progesterone Tetraethylthiuram disulfide Malathion Amittole
5 7 6 12
Nitrosodiphenylamine, IVAniline Lead Chrysene Asbestos
12 !1 12 8 8
Benzene Caffeine Fluoride, sodium Cyclohe~ylamine Heptachlor
15 15 10 10 5
Diazepam DDT Carbon tetrachloride Methyl parathion Dieldrin
7 I1 8 8 6
10
-
-
-
-
-7.1
9.5
- 6.7
12.4
-
5.9 -5.8
9.7 13.1
- 12.9 - 15.2
- 5,1
6.9
-
13.7
-4.7 4.3 -4,2 - 3.8 - 3.7
14.6 15.2 15.7 23.4 13.3
-
18.2 14.5 17.3 23.4 17.7
-
-
13.5
19.7 21.0 10,9 16,8 12.7
-9.6 -9.5
-2.7 -5.8 - 1.6 -6.7
2.0 - 6.5 -7.7
2.3 -3,9
0.2
1.1 3.6 3.5 8.8 5.9 9.0 15.7 10.3
45 TABLE I (continued) Chemical
Phenytoin Toluidine, oTrichloroethylene Benz[a]anthracene Styrene
Number of classes tested 8
12 10 14 11
Agent
Standard deviation
95% lower limit
95% upper limit
-3.3 -3.3 -2.3 - 1.4
17.6 10.7 12.0
- 1.3
15.0
- 18.1 - 10.1 - 10.9 - 9.8 - 11.4
11A 3.5 6.2 6.9 8.8
26.0 14.7 16.4 23.2 ! 6.5
- 21.2 -14.1 - 11.3 - 19.6 - 9.4
18.9 13.1 10.7 19.1 9.8
! 3.2
- 6.8
7.8
17.4
- 9.5
10.6
12.1 19.6 12.5
-5.5 - 19.8 -9.1
7.0 21.4 11.8
13.1
20.5 10.5
- 6.9 - 14.0 -6.7
9.8 17.5 10.9
14.5
- 5.9
10.8
16.6
-7.8
13.3
score
14.4
Hexachlorocyclohexane Pentachlorophenol Dimethoate Fluorouracil, 5Vinyl chloride
9 7 11 14
1.2 -0.5 -0.3 -0.3 0.2
Acrylonitrile Nitro-o-phenylenediamine, pDiethylstilboestrol Malonaldehyde TCDD, 2,3,7,8-
15 14 17 6 8
0.5 0.6 0.8 0.8 1.4
Naphthylamine, 1Vinylidene chloride Auramine Cadmium Methotrexate
12 9 8 14 12
1.5 1.7 2.1 2.4 2.7
2,4-D MCPA Aldrin Procarbazine HCI BenwI chloride
13 7 8 18 13
3.1 3.3 3.3 3.4 3.6
19.9 16.7 15.0 15.1 14.5
-8.9 - 12.1 -9.2 -4.2 -5.2
15.2 18.7 15.9 10.9 12,4
Dimethylcarbamoyl chloride Azathioprine Dibromochloropropane Nickel Benzidine
13 9 8 10 13
4.9 4.9 5.7 5.8 5.9
16.9 10.5
-5.3 -3.2
15,1 13.0
12.3
- 4.5
16.0
13.6
- 4.0
15.5
10,8
- 0.7
! 2,4
Hycanthone methanesulfonate Acetaldehyde Ethylene dibromide Diethyl sulphate Tris (2,3-dibromopropyl) PO 4
11 8 11 8 12
6.0 6.0 6.6 7.1 7.8
13,5 15,6 19,5 4.9 5.5
-3.1 - %0 - 6.5 3.0 4.3
15,0 19.1 19.7 11.2 11.3
Propylene oxide Arsenic +3 Hydrazine Styrene oxide Naphthylamine, 2-
10 13 11 12 13
7.8 8.0 8.3 8.5 9.1
! 4.8
- 2.8
18.4
20.1 16.2 16.7 10.7
-4.1 -2.6 -2.1 2.6
20.2 19.2 19.1 15.6
Benzo[a]pyrene Formaldehyde Myleran Vincristine sulphate Epichlorohydrin
19 15 12 8 16
9.5 9.7 10.0 10.4 10,6
12.8 14.6 10.4 20.5
3.3 1.7 3.4 - 6.7 4.6
15.7 17.8 16.5 27.5 16.6
8
-
11.3
46 TABLE 1 (continued)
95% upper limit
Chemical
Number of classes tested
Agent score
Standard deviation
95% lower limit
Uracil mustard Cyclophosphamide Mercaptopurine. 6Ethylene oxide Dimethyl sulphate
6 21 10 14 11
11.1 11.3 12.3 12.8 13.9
16.2 7.6 19.9 5.8 5.5
- 5.9 7.8 - 1.9 9.4 10.3
28.1 14.8 26.6 16.1 17.6
CCNU Chlorambucil BIcomycin Vinblastine sulphate MNNG
6 10 16 5 18
14.2 14.6 16.9 18.2 18.3
5.5 11.0 12.6 36.8 19.0
8.4 6.7 10.2 - 27.6 8.9
19.9 22.4 23.6 63.9 27.8
Chloroprene Methyl bromide Chromium +6 BCNU Mcthoxypsoralen, 8 ( + uvr)
6 7 15 12 11
18.3 18.3 19.0 19.5 19.8
16.0 24.7 19.6 7.9 14.4
1.5 - 4.6 8.2 14.5 10.1
35.1 41.2 29.9 24.5 29.5
Melphalan Actinomycin D Cisplatin Aflatoxin BI
10 10 13 18
23.1 23.1 23.3 24.7
11.6 19.9 9.2 15.8
14.8 8.9 17.7 16.8
31.4 37.3 28.9 32.5
Thiotepa
13
25.9
7.1
21.6
30.2
Nitrogen mustard Adriamycin
1! 13
26,7 29.2
10.8 18.3
19.5 18.2
33.9 40.3
Triaziqunne
11
49.7
17.8
37.7
61.6
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43
© 1992 Elsevier Science Publishers B.V. All fights reserved 0027-5107/92/$05.00
MUTREV 07313
IHTERNATIONAL COHHISSIO~ FOR PROTECTION AGAINST ENVIRONHENTAL HUTAGENS AND CARCINOGENS
A method for comparing and combining short-term genotoxicity test data: Results and interpretation M.L. M e n d e l s o h n a, D . H . M o o r e II a a n d P . H . M . L o h m a n b a Biomedical Sciences, Lawrence Livermore National Laboratory, P.O. Box 5507, Livermore, CA 94550 (U.S.A.) and b MGC - - Laboratory of Radiation Genetics and Chemical Mutagenesis, University of Leiden (The Netherlands)
(Received 9 September 1991) (Accepted 7 October 1991)
Keywords: Short-term genotoxicity test data, comparing and combining; Test data, genotoxicity; Composite scoring system
In the previous papers in this series, we describe a general approach toward creating a composite scoring system for genotoxicity testing. The method combines dose, metabolic activation and sign of outcome information in a way that accommodates negative and positive outcomes. It organizes the data hierarchically into replicates within a given test, tests within a class, classes within families, and finally families within a single agent score for each chemical (Lohman et al., 1992). We developed an optimized method to use close information in such a system (Moore et al., 1992), and we applied the method to a sizable dataset prepared by Waters et al. (1988) for the International Agency for Research on Cancer (IARC). This paper summarizes and tries to interpret the overall behavior of the system, including the relationships among its components, its statistical properties, our understanding of its mechanisms, its potential for future development, and what it
Correspondence: Dr. M.L. Mendelsohn, Biomedical Sciences, Lawrence Livermore National Laboratory, P.O. Box 5507, Livermore, CA 94550 (U.S.A.).
might be telling us about environmental mutagenicity testing. Detailed chemical results will be presented in later papers, as will the relationship of the present data to the corresponding system that has been developed for carcinogenesis (Nesnow, 1990). The experience to be described is limited to using the system to estimate general genotoxicity; the system has yet to be adapted or applied to other targets such as genotoxicity in the contexts of carcinogenicity or heritable mutation. The database
The database presently contains 113 chemicals which meet the minimal criteria of 3 conventional tests in vitro and 2 conventional tests in vivo. it includes 85 tests which meet the minimal criterion of at least 5 cltcmicals per test. Detail on the data is given in ~'~e two previous papers. For present purposes ~t is important to know that collection and am~otation of the material was done by expert committees in the context of the IARC process of reviewing chemicals for their poten,~i~O carcinogenicity. The data thus come
44 TABLE 1 C H E M I C A L S O R D E R E D BY A G E N T S C O R E W I T H R E L A T E D S T A T I S T I C S Chemical
N u m b e r of classes tested
Agent score
Standard deviation
95% lower limit
95% upper limit
Ethanol Melamine Chlorodifluoromethane C.I. acid red 14 Pentachloronitrobenzene
16 5 7 6 6
-27.7 - 26.4 -26.1 - 23.3 - 20.5
15.1 4.3 16.4 6.1 7.4
-35.7 - 31.7 -41.2 - 29.7 - 28.2
-
Saccharin Halothane Isoniazid Phenylbutazone Caprolactam
11 9 1! 7 l0
-
18.8 18.7 18.6 18.4 18.2
14.0 25.2 10.3 5.8 12.6
-28.2 -38.0 -25.5 -23.8 - 27.2
-9.4 0,7 - 11,7 - 13,0 - 9,2
Diethylhexylphthalate Polychlorinated biphenyls Ethylenethioarea Saccharin, sodium Methoxychlor
15 8 14 15 7
-
17.4 16.9 16.8 15.8 15.7
15.1 12.1 14.0 16.4 15.2
- 25.7 -27.0 - 24.9 -24.8 -29.8
- 9,0 -6.8 - 8.7 -6.7 - 1.7
Polybrominated biphenyls Chloroform Chloramphenicol Metronidazole Maleie hydrazide
6 13 8 i2 9
15.5 15.3 - 15.1 - 14,8 - 14,1
5.5 9.6 14.8 14.1 16.3
- 21.3 -21.1 -27.5 - 23.7 -26.7
- 14,1 - 13,9 - 13,5 - 13,2 - 12,8
10.2 23.6 7.6 9.9 18,0
-21.4 - 29.7 - 20,5 - 18.7 -27.9
12,4 12,1 11.9 I 1.3 10.7
6,9 8.8 20.3 20.9 20.1
-21.0 -20.3 - 33.2 - 26.3 - 23.4
-3.9 9.4 3.7 2.1
-9,7 -8.9
8.6 10.5
- 8,7
14.0
-8.6 - 8,4
15.0 ! 5.0
- 15.2 - 16.0 - 17.6 -21.1 - 20.9
-4.3 - 1.8 0.2 4.0 4. I
- 12.4
- 1.9
Trichloroethane, 1,1.1-
I0
Dichlor~melhane
II 7 15
Tetrachloroethylene Phenobarbital
Endrin
8
Mestranol Progesterone Tetraethylthiuram disulfide Malathion Amittole
5 7 6 12
Nitrosodiphenylamine, IVAniline Lead Chrysene Asbestos
12 !1 12 8 8
Benzene Caffeine Fluoride, sodium Cyclohe~ylamine Heptachlor
15 15 10 10 5
Diazepam DDT Carbon tetrachloride Methyl parathion Dieldrin
7 I1 8 8 6
10
-
-
-
-
-7.1
9.5
- 6.7
12.4
-
5.9 -5.8
9.7 13.1
- 12.9 - 15.2
- 5,1
6.9
-
13.7
-4.7 4.3 -4,2 - 3.8 - 3.7
14.6 15.2 15.7 23.4 13.3
-
18.2 14.5 17.3 23.4 17.7
-
-
13.5
19.7 21.0 10,9 16,8 12.7
-9.6 -9.5
-2.7 -5.8 - 1.6 -6.7
2.0 - 6.5 -7.7
2.3 -3,9
0.2
1.1 3.6 3.5 8.8 5.9 9.0 15.7 10.3
45 TABLE I (continued) Chemical
Phenytoin Toluidine, oTrichloroethylene Benz[a]anthracene Styrene
Number of classes tested 8
12 10 14 11
Agent
Standard deviation
95% lower limit
95% upper limit
-3.3 -3.3 -2.3 - 1.4
17.6 10.7 12.0
- 1.3
15.0
- 18.1 - 10.1 - 10.9 - 9.8 - 11.4
11A 3.5 6.2 6.9 8.8
26.0 14.7 16.4 23.2 ! 6.5
- 21.2 -14.1 - 11.3 - 19.6 - 9.4
18.9 13.1 10.7 19.1 9.8
! 3.2
- 6.8
7.8
17.4
- 9.5
10.6
12.1 19.6 12.5
-5.5 - 19.8 -9.1
7.0 21.4 11.8
13.1
20.5 10.5
- 6.9 - 14.0 -6.7
9.8 17.5 10.9
14.5
- 5.9
10.8
16.6
-7.8
13.3
score
14.4
Hexachlorocyclohexane Pentachlorophenol Dimethoate Fluorouracil, 5Vinyl chloride
9 7 11 14
1.2 -0.5 -0.3 -0.3 0.2
Acrylonitrile Nitro-o-phenylenediamine, pDiethylstilboestrol Malonaldehyde TCDD, 2,3,7,8-
15 14 17 6 8
0.5 0.6 0.8 0.8 1.4
Naphthylamine, 1Vinylidene chloride Auramine Cadmium Methotrexate
12 9 8 14 12
1.5 1.7 2.1 2.4 2.7
2,4-D MCPA Aldrin Procarbazine HCI BenwI chloride
13 7 8 18 13
3.1 3.3 3.3 3.4 3.6
19.9 16.7 15.0 15.1 14.5
-8.9 - 12.1 -9.2 -4.2 -5.2
15.2 18.7 15.9 10.9 12,4
Dimethylcarbamoyl chloride Azathioprine Dibromochloropropane Nickel Benzidine
13 9 8 10 13
4.9 4.9 5.7 5.8 5.9
16.9 10.5
-5.3 -3.2
15,1 13.0
12.3
- 4.5
16.0
13.6
- 4.0
15.5
10,8
- 0.7
! 2,4
Hycanthone methanesulfonate Acetaldehyde Ethylene dibromide Diethyl sulphate Tris (2,3-dibromopropyl) PO 4
11 8 11 8 12
6.0 6.0 6.6 7.1 7.8
13,5 15,6 19,5 4.9 5.5
-3.1 - %0 - 6.5 3.0 4.3
15,0 19.1 19.7 11.2 11.3
Propylene oxide Arsenic +3 Hydrazine Styrene oxide Naphthylamine, 2-
10 13 11 12 13
7.8 8.0 8.3 8.5 9.1
! 4.8
- 2.8
18.4
20.1 16.2 16.7 10.7
-4.1 -2.6 -2.1 2.6
20.2 19.2 19.1 15.6
Benzo[a]pyrene Formaldehyde Myleran Vincristine sulphate Epichlorohydrin
19 15 12 8 16
9.5 9.7 10.0 10.4 10,6
12.8 14.6 10.4 20.5
3.3 1.7 3.4 - 6.7 4.6
15.7 17.8 16.5 27.5 16.6
8
-
11.3
46 TABLE 1 (continued)
95% upper limit
Chemical
Number of classes tested
Agent score
Standard deviation
95% lower limit
Uracil mustard Cyclophosphamide Mercaptopurine. 6Ethylene oxide Dimethyl sulphate
6 21 10 14 11
11.1 11.3 12.3 12.8 13.9
16.2 7.6 19.9 5.8 5.5
- 5.9 7.8 - 1.9 9.4 10.3
28.1 14.8 26.6 16.1 17.6
CCNU Chlorambucil BIcomycin Vinblastine sulphate MNNG
6 10 16 5 18
14.2 14.6 16.9 18.2 18.3
5.5 11.0 12.6 36.8 19.0
8.4 6.7 10.2 - 27.6 8.9
19.9 22.4 23.6 63.9 27.8
Chloroprene Methyl bromide Chromium +6 BCNU Mcthoxypsoralen, 8 ( + uvr)
6 7 15 12 11
18.3 18.3 19.0 19.5 19.8
16.0 24.7 19.6 7.9 14.4
1.5 - 4.6 8.2 14.5 10.1
35.1 41.2 29.9 24.5 29.5
Melphalan Actinomycin D Cisplatin Aflatoxin BI
10 10 13 18
23.1 23.1 23.3 24.7
11.6 19.9 9.2 15.8
14.8 8.9 17.7 16.8
31.4 37.3 28.9 32.5
Thiotepa
13
25.9
7.1
21.6
30.2
Nitrogen mustard Adriamycin
1! 13
26,7 29.2
10.8 18.3
19.5 18.2
33.9 40.3
Triaziqunne
11
49.7
17.8
37.7
61.6
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