CAS-NEN-1 and CAS-NEN-4 (derived from neuroendocrine carcinomas (NECs), with >50% positive Ki67 staining), CAS-NEN-2 (grade G2, with 3 to 20% positive Ki67 staining) and CAS-NEN-3 (grade G1, with <3% positive Ki67 staining), originating from pancreatic NENs, showed extensive neuroendocrine features, including islet morphology and positivity for Synaptophysin (SYP) and CHGA staining both in organoid culture and when engrafted in vivo (Fig. 1e and Supplementary Fig. 1d). Here, SYP is linked to neuroendocrine carcinoma.