Histologically, high-grade, intraepithelial neoplasia/carcinoma in situ were seen in the antrum of Mist1-CreERT; Apcflox/flox mice around 60 days after tamoxifen induction, which expanded further by day 120 but remained intra-mucosal without invasion (Supplementary Figure 3D). Here, BHLHA15 is linked to in situ carcinoma.