Although pCR is uncommon after NET, prognosis seems favourable in most cases.5,6 Ki-67 expression, before and especially under endocrine treatment, has been shown to predict relapse-free survival (RFS) in the IMPACT trial.7,8 Based on patients included in the P024 trial, Ellis et al. developed a preoperative prognostic index (PEPI score) validated in an independent cohort of patients from the IMPACT study.5,9,10 It combines the post-treatment Ki-67 level with ER status, pathological tumour size and nodal status. This evidence concerns the gene MKI67 and neoplasm.