Table 3. Safeguarding strategies in pluripotent stem cells.

Vector	Promoter	Suicide gene	Cell types	Function	Reference
Non-viral plasmid	PGK	HSV-TK	hESCs	Ablation of teratomas	43
Lentivirus	Ubiquitin C	HSV-TK	mESCs	Prevention of teratoma formation	42
Lentivirus	CMV	HSV-TK	mESCs	Ablation of teratoma formation	41
Knock-in at the endogenous locus of OCT4	OCT4	HSV-TK	mESCs	Prevention of teratoma formation in spheroids culture	46
Non-viral plasmid	OCT4	HSV-TK	mESCs	Prevention of teratoma formation	47
SSEA5	NA	Anti-SSEA5 antibody	hESCs/hiPSCs	Prevention of teratoma formation	44
Lentivirus	SFFV	CD/ iCaspase9	Macaca nemestrina iPS cells	Prevention and ablation of teratoma formation	51
Non-viral plasmid	mifepristone-inducible promoter (GAL4 UAS)	Caspase-1	mESCs	Ablation of teratoma formation	45
Knock-in at the endogenous locus of Nanog	Nanog	Enhanced mutant version of HSV-TK	hESCs	Prevention of teratoma formation	50
Lentivirus	EF1a/Nanog	DeltaTK/CD	hESCs/hiPSCs mECSs/miPSCs	Prevention and ablation of teratoma formation	52, 53