FGF10 and pleuropulmonary blastoma: Expression of Etv5, another FGF10 target, was also significantly reduced in Yy1flox/flox;Shh+/Cre mutants, and a similar observation was made in PPB patients, in whom ETV5 expression was 5.1-times lower than in controls (Padj<0.0001; Fig. 1; Table S4).