Table 2. Examples of genetically engineered animal tumor models in breast cancer.

Promoter	Origin	Activation	Transgene	Active protein	Primary tumor		Metastasis			Pathology	Subtype
					Incidence (%)	Latency (week)	Incidence (%)	Latency	Metastatic site
MMTV-LTR	Mouse mammary tumor virus	Steroid hormones	neu/ErbB2	Receptors	100	30	75	32	Lung	Adenocarcinoma, metastatic	luminal	[62]
			PyMT	Viral oncogenes	100	4-8	84-90	14	Lung, lymph node	Multifocal adenocarcinomas		[63]
			Cyclin D1	Cell cycle	40	88	-	-	-	Mammary gland adenocarcinomas		[64]
			Myc	Cell cycle	60	-	-	-		Mammary gland adenocarcinomas		[65]
			Wnt1	Differentiation	60	32	*			Mammary gland adenocarcinomas		[66]
C(3)1	Rat prostate steroid-binding protein (PSBP)	Estrogen	SV40 Tag	Viral oncogenes	90	21	*		Lung, lymph node	Mammary gland adenocarcinomas	Basal	[50]
WAP	Whey acidic protein	Lactogenic hormones	Ras	Others	100	24	14	-	Lung	Adenocarcinoma genomic instability		[53]

^*Metastasis/tumor appearance but not incidence was reported.