In our cohort, NEC histology and high Ki-67 index (> 55%) were significant prognostic factors for PFS (HR 3.31 and 2.94, respectively) and OS (HR 4.23 and 3.81, respectively), with histology being an independent prognosticator for OS in multivariable Cox regression analysis. The gene discussed is MKI67; the disease is neuroendocrine carcinoma.