For example, constitutive activation of MST4 (Sox9‐CreERT2;Mst4T178E/T178E) or heterozygous mutation of β‐catenin T40D mimicking its phosphorylation by MST4 in ISCs substantially increased the number of ISCs/CSCs and exacerbated CRC. The gene discussed is SOX9; the disease is colorectal carcinoma.