Table 2.

Preclinical Murine Models of Human Cancer

Model	Main components	Advantages	Limitations	Time and Cost*
Xenograft (cell line)	Immortalized human tumor cell lines transplanted into immunodeficient host (mouse)	Numerous established and well-annotated cell lines	Immunodeficient host	2–4 wk, $
		Representation from various human tumor types	Subcutaneous location may not allow cultivation of key tissue-specific stromal infiltrate
		Features of tumor microenvironment, including stromal and vascular cells, incorporated within tumor	Cross-species divide; stromal components are mouse, whereas tumor cells are human
		Tumors are easily and precisely measured	Limited or no genetic heterogeneity present within tumor
Xenograft (patient-derived)	Human tumor explant propagated in immunodeficient host (mouse)	Heterogeneity and genetic diversity within tumors	Immunodeficient host	8–24 wk†, $$$
		Representation from various human tumor types	Subcutaneous location may not allow cultivation of key tissue-specific stromal infiltrate
		Features of tumor microenvironment, including stromal and vascular cells, incorporated within tumor	Surgical implantation required
		Tumors are easily and precisely measured	Cross-species divide; stromal components are mouse, whereas tumor cells are human
			Genetic and phenotypic drift with passage
Syngeneic	Immortalized mouse tumor cell line allografted into immunocompetent host (mouse)	Presence of intact immune system	Limited number of established cell lines, which are poorly annotated	2–4 wk, $
		Features of tumor microenvironment, including stromal and vascular cells, incorporated within tumor	Strong immunogenicity of some lines promotes spontaneous regression
		All cell types within tumor are of mouse origin	Rapid growth rate of many lines limits use in longer-term studies
		Tumors are easily and precisely measured
GEMMs	Genetic modification that permits induced or spontaneous tumor development	Tumors develop in tissue of origin	Limited genetic mosaicism and heterogeneity of tumors	12–24 wk†, $$
		Presence of intact immune system	Technical hurdlesfor monitoring tumor response in internal organs
		All cell types within tumor are of mouse origin	Low throughput and high investment
		Features of tumor microenvironment, including stromal and vascular cells, and immune system components

^*=low

^$=low

^$$=intermediate cost

^$$$=high cost.

^†Up to 1 y to observe metastases.

Adapted with permission of (21).