Moreover, the OSKM approach to promote pluripotency was effective only on a limited subset of cancer types.18 The shortcomings of OSMK may be due to the presence of oncongenic factors (c-Myc and Klf4) or to the intrinsic defects of the strategy.19, 20 Most importantly, these shortcomings hinder the use of OSKM approach to investigate tumor progression in reprogrammed cancer cells. Here, KLF4 is linked to cancer.