FGF19 and hepatoblastoma: Since FGF19 expression colocalized to a subset of cells within the embryonal components of hepatoblastoma that showed high levels of both nuclear β-catenin and Wnt target gene expression (Fig. 2b-c, e-h, Fig. 3a-c), we asked whether the upregulation of FGFs in these tumoroids depended on β-catenin.