MKI67 and neuroendocrine carcinoma: The Nordic NEC trial reported different response rates and outcomes by dividing the cohort at the cut-off level of a Ki67 rate of 55%: whereas the subgroup of highly proliferative NEN G3 (Ki67 ≥ 55%) showed a response rate (RR) of 42% to platinum-based chemotherapy but a poor prognosis with a median OS of 10 months, the subgroup with Ki67 < 55% demonstrated limited response to this chemotherapy with an RR of 15% but a better OS of 14 months [16].