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Study Information
Study Attribute Value
CEBS Accession Number: 002-01553-0002-0000-8
Chemical Name: 6-Mercaptopurine
CASRN: 50-44-2
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 310403_CA
Study Result: Positive

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

Trial #:1   Activation: No Activation    Date: 08/13/1986    Harvest Time: 17 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: Dimethyl Sulfoxide 
0         
 200 3 0.015 1.0 0 0.000 0.0 3 0.015 1.0 0 0.000 0.0
Test Chemical: 6-Mercaptopurine 
100         
 200 12 0.060 6.0 1 0.005 0.5 11 0.055 5.5 0 0.000 0.0 
160         
 200 16 0.080 7.0 1 0.005 0.5 15 0.075 6.5 0 0.000 0.0 
300         
 200 17 0.085 7.0 2 0.010 1.0 15 0.075 6.0 0 0.000 0.0 
500         
 200 14 0.070 7.0 4 0.020 2.0 10 0.050 5.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.0625    
 200 35 0.175 14.5 14 0.070 5.5 21 0.105 10.0 0 0.000 0.0
Mitomycin-C 
 0.25      
 50 32 0.640 40.0 17 0.340 26.0 15 0.300 20.0 0 0.000 0.0
Trend: 2.494 2.270 1.736  
Probability: 0.006 0.012 0.041  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 06/17/1986    Harvest Time: 13 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: Dimethyl Sulfoxide 
0         
 200 6 0.030 1.5 0 0.000 0.0 6 0.030 1.5 0 0.000 0.0
Test Chemical: 6-Mercaptopurine 
160         
 200 5 0.025 2.5 0 0.000 0.0 5 0.025 2.5 0 0.000 0.0 
300         
 200 11 0.055 5.5 2 0.010 1.0 9 0.045 4.5 0 0.000 0.0 
500         
 200 10 0.050 4.0 2 0.010 1.0 8 0.040 3.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
2.5       
 200 33 0.165 15.5 4 0.020 2.0 29 0.145 13.5 0 0.000 0.0
Cyclophosphamide 
7.5       
 50 22 0.440 34.0 4 0.080 8.0 18 0.360 26.0 0 0.000 0.0
Trend: 1.895 1.820 1.279  
Probability: 0.029 0.034 0.100  


Trial #:2   Activation: No Activation    Date: 06/17/1986    Harvest Time: 13 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: Dimethyl Sulfoxide 
0         
 200 3 0.015 1.5 1 0.005 0.5 2 0.010 1.0 0 0.000 0.0
Test Chemical: 6-Mercaptopurine 
100         
 200 14 0.070 6.5 1 0.005 0.5 13 0.065 6.0 0 0.000 0.0 
160         
 200 12 0.060 6.0 0 0.000 0.0 12 0.060 6.0 0 0.000 0.0 
300         
 200 9 0.045 4.5 0 0.000 0.0 9 0.045 4.5 0 0.000 0.0 
500         
 200 4 0.020 2.0 0 0.000 0.0 4 0.020 2.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.0625    
 200 60 0.300 23.5 22 0.110 10.5 38 0.190 16.0 0 0.000 0.0
Mitomycin-C 
 0.25      
 50 40 0.800 48.0 20 0.400 30.0 20 0.400 36.0 0 0.000 0.0
Trend: -0.273 -1.478 0.062  
Probability: 0.607 0.930 0.475