As expected, PanNECs frequently exhibited alterations in TP53, RB1, and CDKN2A, but also in KRAS and SMAD4. In contrast, G3PanNETs harbored NET-typical gene alterations, including MEN1, DAXX, ATRX, TSC2, SETD2, and CDKN2A. Furthermore, 35% (6/17) of these NETs exhibited TP53 alterations, which are comparable to our NEC-like G3NETs [26]. This evidence concerns the gene ATRX and neuroendocrine carcinoma.