May 2025—Many pancreatic neuroendocrine tumors fall into two major prognostic subtypes based on DAXX/ATRX-induced alternative lengthening of the telomerase phenotype and alpha- and beta-cell-like epigenomic profiles. However, some do not fit into either subtype. Furthermore, despite advanced genotyping, pancreatic neuroendocrine tumors (PanNET) are generally not well characterized in terms of their histologic and hormonal phenotypes. The authors conducted a study to identify new subgroups of PanNET by extending transcription factor signatures and investigating their correlation with histologic, hormonal, molecular, and prognostic findings. One hundred eighty-five PanNET (165 nonfunctioning and 20 functioning), resected between 1996 and 2023, were classified into the subgroups A1, A2, B, C, and D.