Table 2.

Phenotype of C57BL/6J (B6) backcrossed progeny of a novel cancer model mouse generated by N‐ethyl‐N‐nitrosourea mutagenesis

B6 backcross generation	Sex	No. of animals tested	Osteoma		Breast cancer		Trichogenic tumor
			n	%	n	%	n	%
B6N3	Female	9	6	66.7	9	100.0	0	0.0
	Male	10	10	100.0	0	0.0	8	80.0
B6N4	Female	7	4	57.1	7	100.0	0	0.0
	Male	9	8	88.9	1	11.1	4	44.4
B6N5	Female	12	3	25.0	12	100.0	1	8.3
	Male	13	13	100.0	0	0.0	8	61.5
B6N6	Female	9	6	66.7	9	100.0	1	11.1
	Male	7	7	100.0	1	14.3	5	71.4
B6N7	Female	4	4	100.0	4	100.0	0	0.0
	Male	7	7	100.0	0	0.0	6	85.7
B6N8	Female	8	5	62.5	8	100.0	0	0.0
	Male	14	11	78.6	3	21.4	14	100.0
B6N9	Female	13	5	38.5	13	100.0	2	15.4
	Male	18	17	94.4	2	11.1	13	72.2
B6N10	Female	9	4	44.4	9	100.0	0	0.0
	Male	6	6	100.0	2	33.3	5	83.3
B6N11	Female	10	5	50.0	10	100.0	1	10.0
	Male	17	17	100.0	1	5.9	16	94.1
B6N12	Female	12	6	50.0	12	100.0	3	25.0
	Male	9	8	88.9	1	11.1	9	100.0
B6N13	Female	5	2	40.0	5	100.0	1	20.0
	Male	7	7	100.0	0	0.0	7	100.0
B6N14	Female	9	2	22.2	9	100.0	3	33.3
	Male	6	6	100.0	1	16.7	6	100.0
B6N15	Female	6	5	83.3	6	100.0	2	33.3
	Male	9	8	88.9	1	11.1	9	100.0
B6N16	Female	9	6	66.7	9	100.0	1	11.1
	Male	13	11	84.6	1	7.7	11	84.6
B6N17	Female	2	1	50.0	2	100.0	0	0.0
	Male	19	17	89.5	3	15.8	19	100.0
B6N18	Female	7	7	100.0	7	100.0	1	14.3
	Male	14	13	92.9	1	7.1	14	100.0
B6 backcross total	Female	131	71	54.2	131	100.0	16	12.2
	Male	178	166	93.3	18	10.1	154	86.5
	Total	309	237	76.7	149	48.2	170	55.0

Incidence of cancer phenotypes was examined in B6 backcrossed progeny by moribund necropsies.