Despite the exclusion of equivocal cases (NEC vs. G3-WD-NET) by pathologists, there is still the possibility that some tumours with a low proliferative rate (20% < Ki-67 < 50–55%) were misclassified as NECs rather than G3-WD-NETs, especially those with a non-SC morphology. This evidence concerns the gene MKI67 and neuroendocrine carcinoma.