The H&E (Fig. 5D, left panel) and Masson’s trichrome (Fig. 5D, right panel) staining of E4KO;BKC pancreata revealed a penetration of cancer cells similar to BKC mice, presenting with fibrosis, PanIN, and carcinoma, while the lack of ERBB2 rather resembled atypical flat lesions mixed with ADM and low‐grade PanIN, with an equal amount of fibrosis in BKC pancreata, but with decreased area of (pre‐)neoplastic tissue, and remaining acinar tissue was frequently observed. The gene discussed is ERBB2; the disease is carcinoma.