NEFL and neuroendocrine neoplasm: Strengths of our study include the international multicenter design, a conservative approach to neurologic prognostication, and strict criteria for WLST.19,44 As previously published, serum samples were prospectively collected from all patients at sites participating in the biobank substudy and the number of missing samples was low.17 In contrast to the guideline-recommended biomarker NSE, which is also present in erythrocytes and neuroendocrine tumors, NfL levels are not falsely elevated in the presence of hemolysis.17,27