Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01867-0010-0000-5
Chemical Name:	Chloroform
CASRN:	67-66-3
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	907612
Study Result:	Positive

View Study Details | View Protocol | Download To Excel

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: Inconclusive
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	102	90	86	28	29
			104	96	83	27
			86#	97	84	32
			89	116	75	28
Test Chemical	Chloroform	0.0156	123r	124	96	26
			87	70	83	32
		0.0313	103	121	91	29	28
			85	91	69	27	28
		0.0625	78	85	69	30	30
			107	98	100	31	30
		0.125	99	98	96	32	30
			108	128	87	27	30
		0.25	120	109	91	25	27
			87	87	72	28	27
		0.5	69	64	55	27
Positive Control	Ethyl Methane Sulfonate	500	7r	1	439	2090	1287*
			19#	6	687	1238
			18	7	735	1336

Nonactivation Trial: 2 Experiment Call: Negative
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	100	86	74	25	19
			108	102	64	20
			90	94	47	17
			117	118	52	15
Test Chemical	Chloroform	0.0625	102	108	63	21	17
			86	105	36	14
			80	101	41	17
		0.125	92	61	76	28	22
			106	75	50	16
			84	74	59	23
		0.25	112	97	56	17	15
			88	46	30	11
			88	69	44	17
		0.5	101	48	42	14	22
			92	39	84	30
			125r	79	107	28
		0.75	109	96	74	23	22
			107	65	38	12
			85	13	78	30
		1



Positive Control	Ethyl Methane Sulfonate	500	10	2	453	1461	1182*
			33	12	913	936
			18	6	620	1148

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	82#	112	78	32	33
			87	95	109	42
			72	85	45	21
			81#	107	86	36
Test Chemical	Chloroform	0.78	96	103	144	50	51
			59	59	91	51	51
		1.56	65	69	128	65	53*
			99	81	120	40	53*
		3.13	61	48	71	39	44
			70	49	102	49	44
		6.25	62	20	180	96
		12.5	96	8	301	105	111*
			71#	9	248	117	111*
		25

Positive Control	3-Methylcholanthrene	5	14	2	199	474	398*
			13	2	147	367
			13	2	138	354

Induced S9 Trial: 2 Experiment Call: Equivocal
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	90	104	104	38	34
			78	97	67	29
			78	99	79	34
Test Chemical	Chloroform	0.004	61	67	43	24	24
			75	72	56	25
			61#	66	42	23
		0.006	66	51	55	28	27
			76#	73	54	24
			52	39	47	30
		0.008	63	44	52	28	28
			78	37	63	27
			81	42	74	31
		0.01	59	23	74	42	41
			82	29	101	41
			51	23	61	40
		0.012	80	20	132	55	54*
			77	26	107	46
			81	24	147	60
		0.014	65	16	97	50	53*
			57	18	92	54
			75	17	127	56
Positive Control	3-Methylcholanthrene	5	14	1	186	448	546*
			11	1	195	582
			12	1	210	609

Induced S9 Trial: 3 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	70	102	55	26	26
			58#	83	48	28
			69	111	52	25
			57	104	45	26
Test Chemical	Chloroform	10	46	33	60	44	38
			79	61	77	32	38
		12	62	41	73	39	36
			66	46	68	34
			75	55	75	33
		14	63	35	71	38	43*
			76	39	92	41
			60	36	90	50
		16	64	38	78	41	44*
			65	35	97	50
			59	34	73	41
		18	57	26	104	61	55*
			75	28	111	49	55*
		20	78	34	132	56	47*
			79	37	101	42
			88	38	109	41
Positive Control	3-Methylcholanthrene	2.5	34	18	213	211	229*
			49	33	328	223
			31	16	236	252

Induced S9 Trial: 4 Experiment Call: No Call
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	95	111	86	30	30
			95#	103	91	32
			97	94	98	34
			110#	93	81	25
Test Chemical	Chloroform	5	95	35	119	42	38
			98#	32	150	51
			102#	36	63	21
		10	98#	23	100.5	34	45
			109	23	153	47
			88	22	141	54
		15					62*
			93	13	220	79
			105	11	141	45
		20


Positive Control	3-Methylcholanthrene	2.5	98	74	424	144	150*
Positive Control			100	71	466	156	150*

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