Table 2.

Classifications of Xenograft mouse models.

Basis of classification	Classification	Advantages	Disadvantages
The source of the graft	CDX	Readily available cell lines, vast published literature for reference, and low cost	Tumor heterogeneity was significantly different from the original tumor tissue
	PDX	Tumor heterogeneity was stably retained	Complicated operation unrepeatable modeling, long construction time, high cost, and unstable success rate
The tumor location	Ectopic	Time-saving and less labor	Tumors formed in ectopic sites Rare metastasis and bone invasion are
	Orthotopic	Develop tumors in the oral region Develop bone invasive and distant metastasis	Harder implantation than ectopic xenograft More painful for mice