NET G3 are predominantly defined by a well-differentiated morphology and Ki67 index ranging from 20% mostly up to 55%, whereas NEC G3 present with a poorly differentiated morphology (large-cell or small-cell type) and Ki67 index in the majority of cases above 55% (2, 6, 11, 13). This evidence concerns the gene MKI67 and neuroendocrine carcinoma.