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Study Information
Study Attribute Value
CEBS Accession Number: 002-01863-0001-0000-1
Chemical Name: Chlorobenzene
CASRN: 108-90-7
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 930766_SCE
Study Result: Positive

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

Trial #: 1    Activation: No Activation    Date: 01/25/1985    Trial Call: Positive   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1046 320 0.306 6.40 26.5 0.000
Test Chemical Chlorobenzene 
100         
 50 1046 361 0.345 7.22 26.5 12.813 
300         
 50 1048 415 0.396 8.30 26.5 29.440 
999         
 50 1039 458 0.441 9.16 26.5 44.089
Positive Control Mitomycin-C 
 0.0015    
 50 1050 496 0.472 9.92 26.5 54.410
Mitomycin-C 
 0.01      
 10 209 308 1.474 30.80 26.5 381.711
Trend: 5.392        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 02/06/1985    Trial Call: Positive   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1045 392 0.375 7.84 26.5 0.000
Test Chemical Chlorobenzene 
100         
 50 1042 392 0.376 7.84 26.5 0.288 
300         
 50 1050 467 0.445 9.34 26.5 18.565 
500         
 50 1045 497 0.476 9.94 26.5 26.786 
1000         
 50 1040 531 0.511 10.62 26.5 36.110
Positive Control Mitomycin-C 
 0.0015    
 50 1049 611 0.582 12.22 26.5 55.273
Mitomycin-C 
 0.01      
 10 211 290 1.374 29.00 26.5 266.392
Trend: 5.742        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 01/25/1985    Trial Call: Negative   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1049 376 0.358 7.52 26.0 0.000
Test Chemical Chlorobenzene 
30         
 50 1048 393 0.375 7.86 26.0 4.621 
100         
 50 1047 394 0.376 7.88 26.0 4.987 
300         
 50 1046 372 0.356 7.44 26.0 -0.780
Positive Control Cyclophosphamide 
 0.5       
 50 1050 659 0.628 13.18 26.0 75.099
Cyclophosphamide 
2.5       
 10 211 406 1.924 40.60 26.0 436.823
Trend: -0.073        
Probability: 0.529