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Study Information
Study Attribute Value
CEBS Accession Number: 002-02434-0002-0000-7
Chemical Name: Methyl ethyl ketone peroxide
CASRN: 1338-23-4
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 774268_CA
Study Result: Positive

Study Result: Positive
Activation Trial Trial Call
No Activation  1  Positive 
Induced Rat Liver S9  1_S9  Weakly Positive 
No Activation  2  Weakly Positive 
Induced Rat Liver S9  2_S9  Questionable 

Trial #:1   Activation: No Activation    Date: 06/21/1984    Harvest Time: 12 hour(s)   Trial Call: Positive   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 1 0.010 1.0 0 0.000 0.0 1 0.010 1.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Methyl ethyl ketone peroxide 
20         
 100 4 0.040 4.0 3 0.030 3.0 1 0.010 1.0 0 0.000 0.0 
30         
 100 15 0.150 11.0 10 0.100 8.0 5 0.050 5.0 0 0.000 0.0 
40         
 100 26 0.260 16.0 11 0.110 10.0 14 0.140 8.0 1 0.010 1.0 
50         
 100 10 0.100 8.0 3 0.030 3.0 7 0.070 6.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.25      
 100 31 0.310 23.0 19 0.190 17.0 12 0.120 10.0 0 0.000 0.0
Mitomycin-C 
1         
 50 43 0.860 50.0 26 0.520 34.0 17 0.340 28.0 0 0.000 0.0
Trend: 3.572 2.215 3.191  
Probability: 0.000 0.013 0.001  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 06/21/1984    Harvest Time: 10.8 hour(s)   Trial Call: Weakly Positive   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 2 0.020 2.0 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Methyl ethyl ketone peroxide 
16         
 100 2 0.020 2.0 2 0.020 2.0 0 0.000 0.0 0 0.000 0.0 
25         
 100 2 0.020 2.0 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0 
50         
 100 2 0.020 2.0 0 0.000 0.0 1 0.010 1.0 1 0.010 1.0 
75         
 100 7 0.070 6.0 3 0.030 3.0 4 0.040 4.0 0 0.000 0.0 
75         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
15         
 100 26 0.260 25.0 13 0.130 12.0 13 0.130 13.0 0 0.000 0.0
Cyclophosphamide 
50         
 50 54 1.080 32.0 21 0.420 32.0 13 0.260 26.0 20 0.400 2.0
Trend: 2.406 1.033 2.584  
Probability: 0.008 0.151 0.005  


Trial #:2   Activation: No Activation    Date: 05/23/1984    Harvest Time: 12 hour(s)   Trial Call: Weakly Positive   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 2 0.020 2.0 0 0.000 0.0 2 0.020 2.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Methyl ethyl ketone peroxide 
1.6       
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
5         
 100 2 0.020 2.0 0 0.000 0.0 2 0.020 2.0 0 0.000 0.0 
16         
 100 2 0.020 2.0 2 0.020 2.0 0 0.000 0.0 0 0.000 0.0 
50         
 69 10 0.145 7.0 4 0.058 4.0 6 0.087 4.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.25      
 100 53 0.530 40.0 38 0.380 31.0 15 0.150 13.0 0 0.000 0.0
Mitomycin-C 
1         
 100 72 0.720 48.0 57 0.570 43.0 15 0.150 12.0 0 0.000 0.0
Trend: 3.201 2.762 2.076  
Probability: 0.001 0.003 0.019  


Trial #:2_S9   Activation: Induced Rat Liver S9    Date: 05/22/1984    Harvest Time: 12 hour(s)   Trial Call: Questionable   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 9 0.090 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Methyl ethyl ketone peroxide 
1.6       
 100 2 0.020 2.0 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0 
5         
 100 4 0.040 2.0 1 0.010 1.0 3 0.030 1.0 0 0.000 0.0 
16         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
50         
 100 7 0.070 5.0 3 0.030 3.0 4 0.040 3.0 0 0.000 0.0 
160         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
15         
 100 55 0.550 40.0 31 0.310 25.0 24 0.240 21.0 0 0.000 0.0
Cyclophosphamide 
50         
 50 72 1.440 68.0 34 0.680 48.0 28 0.560 36.0 10 0.200 1.0
Trend: 1.898 1.586 1.586  
Probability: 0.029 0.056 0.056