Similarly, high-grade G3 NECs are defined by morphology and Ki67 expression (>20% but usually <50%).15 The broad interval indicated by Ki67 expression for G3 disease (21–100%) may include a variety of different neoplasms, with potentially different responses to therapies.43 Overall, the morphology-based classification of different categories is still challenging, especially for G3 cases. Here, MKI67 is linked to neoplasm.