While the separation of NET G3 and NEC as different entities has been supported by molecular analyses demonstrating similar genetic alterations in pancreatic NET G3 and pancreatic NET G1/2 (most often mutations in DAXX, ATRX and MEN) and different alterations in NEC (p53 and Rb1) [71,72,73], data on molecular alterations as predictive biomarkers for the choice of treatment are very limited. This evidence concerns the gene RB1 and pancreatic neuroendocrine tumor.