Although both transgenic mouse models developed mucinous lung tumors, induction of SPDEF along with KRASG12D produced malignant mucinous lung tumors (tubulopapillary‐like carcinoma), while induction of FOXA3 along with KRASG12D produced benign mucinous lung tumors (e.g., papilloma). The gene discussed is SPDEF; the disease is papilloma.