RT-PCR analysis of β-catGOF; Mll1−/− organoids confirmed a decreased expression of Gata4 and revealed a concomitant upregulation of Bmp4 and the secretory differentiation markers Mmp7 and Muc2 (Fig. 3f), identifying Mll1 as an upstream regulator of Gata4/Bmp4-controlled cancer stemness and differentiation. Here, MUC2 is linked to cancer.