Chronological and molecular characterization of the lesions developed in Notch1 intracellular domain (Nicd)/Yes-associated protein (Yap) (YapS127A) mice. A: Representative results of the gross and microscopic images of the tumor lesions at different weeks post injection (w.p.i.). Tumor lesions were positive for the cholangiocyte epithelial markers cytokeratin (CK) 19 and SOX9 and negative for the hepatocyte marker hepatocyte nuclear factor 4α (HNF4α), respectively. B: Relative expression of Yap downstream target genes (Cyr61 and Ccn2) in Nicd/Yap of end-stage tumors and wild-type (WT) livers. C: Relative expression of Notch downstream target genes (Hey1, Hey2, HeyL, Hes1, and Hes5) in Nicd/Yap of end-stage tumors and WT livers. Each gene expression was normalized to WT mouse livers with 18S rRNA using the −ΔΔCt method. Data are expressed as means ± SD. ∗P < 0.05, ∗∗P < 0.01 (t-test). Scale bars: 100 μm (second column); 50 μm (third, fourth, fifth, and sixth columns). Original magnification: ×200 (second column); ×400 (third, fourth, fifth, and sixth columns).