“…However, the insertional mutagenic potential of retroviruses combined with the potential for latent reprogramming factor gene activation, especially c-MYC , all but eliminates integrative DNA-based approaches for use in regenerative medicine therapies (Okita and Yamanaka, 2011; González et al, 2011; Hussein et al, 2011; Ben-David and Benvenisty, 2011). Several methods based on DNA, RNA, miRNAs and proteins have been developed to generate integration free iPS cells, and the advantages and disadvantages have been discussed elsewhere (González et al, 2011; Hussein et al, 2011; Mochiduki and Okita, 2012; Okita and Yamanaka, 2011;). Of all these methods, RNA-based iPS cell approaches using Sendai virus (Fusaki et al, 2009), miRNAs and mRNA transfection (Warren et al, 2010) avoid potential integration problems associated with DNA-based approaches and at this point in time, appear inherently safer methods for future clinical applications.…”