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Study Information
Study Attribute Value
CEBS Accession Number: 002-01202-0001-0000-8
Chemical Name: 2,4,5-Trichlorophenoxyacetic acid
CASRN: 93-76-5
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 759776_SCE
Study Result: Positive

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

Trial #: 1    Activation: No Activation    Date: 03/12/1982    Trial Call:   
  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 1040 547 0.526 10.94 25.5 0.000
Test Chemical 2,4,5-Trichlorophenoxyacetic acid 
167         
 50 1038 642 0.618 12.84 25.8 17.594 
500         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C 
 0.005     
 25 520 643 1.237 25.72 25.5 135.101
Trend: 2.788        
Probability: 0.003        

Trial #: 2    Activation: No Activation    Date: 03/25/1982    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 1038 533 0.513 10.66 25.8 0.000
Test Chemical 2,4,5-Trichlorophenoxyacetic acid 
300         
 50 1032 862 0.835 17.24 36.3 62.666 
350         
 50 1039 879 0.846 17.58 36.3 64.757 
400         
 42 862 756 0.877 18.00 36.3 70.799 
450         
 0 0 0 0.000 0.00 36.3 N/A 
500         
 0 0 0 0.000 0.00 36.3 N/A
Positive Control Mitomycin-C 
 0.01      
 25 522 1279 2.450 51.16 25.8 377.167
Trend: 8.821        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 03/12/1982    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 1029 528 0.513 10.56 25.5 0.000
Test Chemical 2,4,5-Trichlorophenoxyacetic acid 
167         
 50 1014 447 0.441 8.94 25.5 -14.089 
500         
 50 1007 481 0.478 9.62 25.5 -6.911 
1670         
 50 1020 500 0.490 10.00 25.5 -4.467
Positive Control Cyclophosphamide 
1.5       
 25 517 847 1.638 33.88 25.5 219.282
Trend: -0.338        
Probability: 0.632        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 03/25/1982    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 1032 503 0.487 10.06 25.8 0.000
Test Chemical 2,4,5-Trichlorophenoxyacetic acid 
1500         
 50 1038 527 0.508 10.54 25.8 4.166 
2000         
 50 1036 805 0.777 16.10 36.3 59.422 
3500         
 0 0 0 0.000 0.00 36.3 N/A 
4000         
 0 0 0 0.000 0.00 36.3 N/A 
4500         
 50 1035 609 0.588 12.18 36.3 20.723 
5000         
 50 1044 706 0.676 14.12 25.8 38.745
Positive Control Cyclophosphamide 
1.5       
 25 524 834 1.592 33.36 25.8 226.548
Trend: 4.439        
Probability: 0.000