Table 1.

Comparison of different protocols for reprogramming human fibroblasts to iPSCs, based on delivery of proteins, DNAs, and cmRNAs of Yamanaka factors

Reprogramming protocols	Protein 17	DNA virus (retrovirus/lentivirus) 18, 19, 20	RNA virus (Sendai virus) 21, 22, 23	cmRNA 7, 24
Time course for colony isolation	8 weeks	2–4 weeks	4 weeks	2 weeks
Reprogramming efficiency	0.001%	0.01%–0.1%	0.01%–1%	Up to 4.4%
Risk of genome integration	No	Yes	No	No

Abbreviations: iPSCs, induced pluripotent stem cells; cmRNA, chemically modified RNA.