RASSF1 and neoplasm: To determine whether tumour formation was due to a failure to control the YAP pluripotency to differentiation switch we isolated mouse embryonic fibroblasts (MEFs) from Rassf1A−/− and Rassf1A+/+ littermates and subjected them to somatic cell reprogramming as previously described54, 55 (Fig. 6a and Supplementary Fig. 8a).