Other prognostic factors had already been identified for patients with NETs, including tumor grade (and percentage of Ki-67–positive tumor cells), tumor heterogeneity (entropy) (22), tumor glucose metabolism assessed by [18F]FDG PET/CT (23), injected activity (24), the size of the largest lesion (for patients receiving salvage PRRT) (25), tumor perfusion and SSTR density (26), molecular profiling (27,28), and inflammation-based indices (29). This evidence concerns the gene MKI67 and neoplasm.