Another possible somatic cell line for reprogramming is primary hepatocytes [37]. This cell type is of endodermal origin and may also be gathered during diagnostic biopsies or surgical interventions. The generation of iPSCs from primary hepatocytes and the following differentiation into cells which are involved in liver specific diseases may be beneficial due to the fact that no germ layer transition between the origin somatic cell and the differentiated liver specific cells generated from iPSCs needs to occur. However, the favoring of differentiation into cell types related to the source cell type for reprogramming is still debated [51]. Subsequently, for example, hepatic progenitor cells or even mature hepatocytes can be further analyzed for drug testing, liver disease modeling, or even therapeutic approaches [37, 77]. The use of patient hepatocyte-derived iPSCs becomes important under distinct circumstances, when somatic mutations are present only in liver cells (this would account also for other organs). This would open the possibility to analyze the disease controlled with mutation-free skin fibroblast from the same patient [37]. It has been published that the reprogramming speed of hepatocytes
