Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01690-0018-0000-7
Chemical Name:	Benzene
CASRN:	71-43-2
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	342509
Study Result:	Negative

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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: Negative
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	89	107	91	34	37
			91	94	120	44
			80	101	83	35
			74	98	77	35
Test Chemical	Benzene	0.0625	70	74	81	38	39
			60	73	66	37
			51	62	63	42
		0.125	80	66	64	27	34
			73#	66	75	34
			72	67	88	41
		0.25	72	59	68	31	39
			74	63	88	40
			64	44	90	47
		0.5	87#	32	113	43
		1	75	14	121	54	48
			74	12	100	45
			78#	16	108	46
		3


Positive Control	Ethyl Methane Sulfonate	250	70	50	740	354	376*
			71	45	843	395
			82	45	931	380

Nonactivation Trial: 2 Experiment Call: Negative
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	100	98	151	50	45
			91#	94	144	53
			113#	108	106	31
Test Chemical	Benzene	0.0313	91	94	88	32	35
			110#	97	126	38	35
		0.0625	95	110	69	24	28
			101	110	101	33
			106	105	88	28
		0.125	107	110	111	35	31
			94	103	81	29
			103	106	91	29
		0.25	100	87	107	36	34
			103	108	91	29
			92	98	102	37
		0.5	116#	78	68	20	29
			112	88	105	31
			77	66	80	35
		1					48
			80#	25	141	59
			84	27	96	38
		3


Positive Control	Ethyl Methane Sulfonate	250	80#	53	859	360	392*
			83	52	912	366
			58	50	789	451

Non-Induced S9 Trial: 1 Experiment Call: Rejected
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	70	143	251	120	120
			78	99	333	143
			80	87	262	109
			60	70	198	111
Test Chemical	Benzene	0.25	65	86	184	95	110
			56	81	212	127
			74#	73	236	107
		0.5	70	42	291	138	156
			54	57	275	170
			54	64	260	161
		0.75	46	8	305	221	217*
			47	42	254	181
			37	14	273	248
		1					191*
			49	18	321	217
			67	43	332	166
		1.5


Positive Control	3-Methylcholanthrene	3.5	62	40	710	381	383*
			58	42	689	393
			64	50	726	376

Non-Induced S9 Trial: 2 Experiment Call: Rejected
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	71	136	114	54	60
			65	101	141	72
			54	60	142	87
			62	103	51	28
Test Chemical	Benzene	0.25	57	39	170	100	102*
			51	33	181	118
			67	55	179	89
		0.5	47	17	158	113	113*
			43	22	144	112
			37	19	127	114
		0.75	28	21	96	114	88
			54#	41	114	70
			67	59	164	81
		1

			60	41	137	76
		1.5


Positive Control	3-Methylcholanthrene	3.5	63	73	237	126	246*
			50	40	289	194
			62	44	772	417

Non-Induced S9 Trial: 3 Experiment Call: Negative
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	77	99	91	39	54
			79#	96	179	76
			81	101	109	45
			80	104	133	55
Test Chemical	Benzene	0.125	77	57	132	57	50
			69	68	107	52
			88	78	111	42
		0.25	60	61	89	49	51
			58#	67	86	49
			55	58	92	55
		0.5	58	65	78	45	54
			60	61	140	77
			62#	62	72	39
		0.75	64	45	135	71	56
			68#	24	135	67
			65	53	61	31
		1	72	45	113	53	51
			49#	19	74	50	51
		1.5	93	29	130	46


		2


Positive Control	3-Methylcholanthrene	3.5	99	71	608	204	194*
			87#	63	538	207
			102#	69	523	171

Non-Induced S9 Trial: 4 Experiment Call: Negative
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	67	113	58	29	38
			65	105	84	43
			68	97	74	37
			71	86	88	41
Test Chemical	Benzene	0.125	72	68	113	52	43
			63	64	57	30
			63#	71	86	46
		0.25	67	69	68	34	40
			61	61	80	44
			76	87	94	42
		0.5	65	54	105	54	49
			63	67	100	53
			75	62	90	40
		0.75	72	47	134	62	51
			58	71	88	50
			63	16	76	40
		1	71	72	71	33	40
			66	46	84	43
			78	22	100	43
		1.5	64	6	111	58


		2


Positive Control	3-Methylcholanthrene	3.5	87	93	332	128	132*
			94#	88	378	135
			87	78	349	133

Induced S9 Trial: 1 Experiment Call: Inconclusive
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	101	125	142	47	55
			82	49	139	56
			90	109	153	57
			80	118	146	61
Test Chemical	Benzene	0.0625	95	106	130	46	54
			77	121	131	57
			72	116	128	59
		0.125	89	78	183	68	59
			82	115	145	59
			73	83	110	50
		0.25	66	84	127	64	57
			71	119	115	54
			66	113	106	54
		0.5	81	73	101	41	51
			85	91	145	57
			102	46	169	55
		1					84
			74	38	179	80
			73	32	193	88
		2


Positive Control	3-Methylcholanthrene	2.5	77	60	501	218	224*
Positive Control			92	74	639	231	224*

Induced S9 Trial: 2 Experiment Call: Inconclusive
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	99	91	141	47	50
			118	109	148	42
			110	93	162	49
			99	106	186	62
Test Chemical	Benzene	0.0625	85	97	124	49	56
			66#	88	149	76
			87#	88	111	42
		0.125	85	90	96	38	45
			75	83	103	46
			76	93	120	53
		0.25	85	94	122	48	61
			73	79	160	74
			82	77	152	62
		0.5	93	56	165	59	53
			101	70	168	56
			116	72	151	43
		1


Positive Control	3-Methylcholanthrene	2.5	95	76	501	176	187*
			81#	69	457	189
			87	72	508	195

Induced S9 Trial: 3 Experiment Call: Negative
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Ethanol	0	90	115	204	75	70
			80	94	170	71
			97	99	207	71
			96	92	184	64
Test Chemical	Benzene	62.5	80	65	112	47	59
			76	61	119	52
			70	60	166	79
		125	71	56	154	72	64
			91	59	166	61
			90	63	162	60
		250	74#	55	234	106	88
			69	48	196	94
			82	61	156	64
		500	89	45	241	91	95
			72	31	220	101
			62	28	174	94
		750	81	19	213	87	96
			80	19	215	89
			60	9	201	111
		1000

			72	14	215	100
		1500


Positive Control	3-Methylcholanthrene	2.5	52	25	680	435	470*
			45	20	666	490
			35	8	514	487

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