Here, we want to sum up the hard facts on the different primary somatic cell sources. Realistically, most laboratories will most probably stay with their method of reprogramming, using the established somatic cell type. Skin fibroblasts will certainly maintain their position as the most commonly used cells. This is due to the fact that these cells are (1) cheap and easy in their maintenance, (2) have a high viability and culture stability over 5–10 passages, and (3) although they have a low reprogramming efficiency, they will mostly facilitate a successful iPSC generation. In addition, (4) the adaptation to almost all integration free methods has been broadly investigated, and (5) most iPSC banking has been performed up to now with this cell type.
