Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01687-0002-0000-6
Chemical Name:	Benz(a)anthracene
CASRN:	56-55-3
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	G62003
Study Result:	Positive

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Table Instructions and Notes:
Studies are indicated to be "Nontoxic" when the observed reductions in relative total growth did not indicate that the maximum tolerated dose was achieved.

Nonactivation Trial: 1 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	115	111	106	31	33
Vehicle Control			88	89	92	35	33
Test Chemical	Benz(a)anthracene	10.2	86	81	77	30	41
			96	89	147	51	41
		25.6	83	78	124	50	50
			78	76	116	49	50
		64	83	49	139	56	70*
			69	39	174	84	70*
		160	81	30	133	55	63*
			77	41	163	71	63*
		400	67	25	205	102	101*
			75	30	227	101	101*
		1000	60	18	153	85	92*
			69	15	207	100	92*
Positive Control	Ethyl Methane Sulfonate	500	34	26	716	695	681*
Positive Control			35	29	696	666	681*

Nonactivation Trial: 2 Experiment Call: No Call
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	101	104	123	41	38
Vehicle Control			111	96	115	34	38
Test Chemical	Benz(a)anthracene	4.1	113	98	136	40	41
			110	113	137	42	41
		10.2	131r	130	167	42
			119	119	118	33
		25.6	125r	108	82	22
			118	102	141	40
		64	105	80	139	44
			132r	90	93	23
		160	116	83	132	38	45
			100	71	158	53	45
		400
			102	40	149	49
		1000

Positive Control	Ethyl Methane Sulfonate	500					702*
Positive Control			52	26	1088	702	702*

Nonactivation Trial: 3 Experiment Call: Negative and Non-Toxic
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	89	82	81	30	24
			97	116	67	23
			93	104	60	22
			103	99	62	20
Test Chemical	Benz(a)anthracene	108	107	78	73	23	31
			90	70	95	35
			94	74	97	35
		134	84	73	100	40	35
			119	91	126	35
			97	75	85	29
		168	105	77	61	19	30
			96	70	96	33
			87	63	96	37
		210	88	64	63	24	34
			71	52	85	40
			90	60	104	39
		262	86	56	86	33	32
			104	67	101	33
			95	67	84	30
		328	80	41	96	40	36*
			84	45	84	33
			89	52	91	34
Positive Control	Ethyl Methane Sulfonate	500	49	33	904	617	594*
			53	37	940	595
			54	38	928	571

Nonactivation Trial: 4 Experiment Call: Negative and Non-Toxic
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	128r	118	189	49	44
			108	112	153	47
			100	102	128	43
			94	86	119	42
Test Chemical	Benz(a)anthracene	81	106	81	148	47	40
			110	102	127	39
			115	117	124	36
		108	109	52	113	35	39
			104	61	133	42
			102	103	122	40
		144	117	94	231	66	53
			109	96	158	48
			106	97	147	46
Positive Control	Ethyl Methane Sulfonate	500	66	46	1320	663	643*
			60	25	1188	656
			73	22	1332	608

Non-Induced S9 Trial: 1 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	85	103	103	40	43
Vehicle Control			89	97	119	45	43
Test Chemical	Benz(a)anthracene	2.7	72	81	110	51	66
			79	96	190	81	66
		3.6	73	74	128	59	57
			68	88	114	56	57
		4.7	70	69	210	101	93*
			92	79	232	84	93*
		6.3	77	62	188	82	83*
			92	66	230	84	83*
		8.4	77	50	318	137	129*
			83	41	299	121	129*
		11.3	42	6	288	229	206*
			46	6	252	184	206*
		15

Positive Control	3-Methylcholanthrene	6	80	56	494	205	203*
Positive Control			66	49	399	201	203*

Induced S9 Trial: 1 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	111	109	64	19	18
Vehicle Control			89	91	47	18	18
Test Chemical	Benz(a)anthracene	3.9	90	87	39	14	21
			89	88	71	27	21
		4.9	102	77	90	29	28
			98	67	80	27	28
		6.1	92	72	75	27	30
			99	65	95	32	30
		7.7	74	51	77	35	28
			82	48	54	22	28
		9.6	56	18	106	63	63*
			63	17	119	63	63*
		12

Positive Control	3-Methylcholanthrene	6	59	34	305	172	186*
Positive Control			61	28	365	199	186*

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	93	103	284	102	113
Vehicle Control			90	97	337	124	113
Test Chemical	Benz(a)anthracene	3.9	84	85	396	157	158
			83	75	395	159	158
		4.9	65	54	445	227	216*
			68	50	419	206	216*
		6.1	69	34	436	211	226*
			60	28	432	241	226*
		7.7	62	18	475	257	244*
			61	20	424	232	244*
		8.5	49	13	454	307	320*
			54	12	539	333	320*
		9.5	46	6	504	367	347*
			51	8	502	328	347*
		10.5

Positive Control	3-Methylcholanthrene	5	43	23	475	373	359*
Positive Control			51	23	531	346	359*

Footnotes:
Asterisks(*) indicate significant responses.
r = rejected value due to quality control criteria
# = reduced sample size because of the loss of one culture dish due to contamination