YAP1 and neoplasm: While most EGFP-positive cells showed proliferative activity when assessed at P7 (Fig. 2e, f), only about one-fifth (16.8 ± 2.63%) of EGFP-positive tumor cells (expressing exogenous YAP1-MAMLD1) were also proliferating (Ki67-positive) (the mean ± S.D., n = 6, Fig. 3n–v), potentially indicating intra-tumoral heterogeneity in established YAP1-MAMLD1-driven tumors.