The primary data extracted from medical records include age, gender, functional syndrome, familial hereditary syndrome, interval between symptom onset and NEN diagnosis, diagnostic procedures at the time of initial diagnosis, primary tumor location, histopathological features (in line with the WHO classification) [9], immunohistochemical characteristics, Ki67 value, tumor stage at diagnosis, therapeutic interventions, data on time and mode of tumor recurrence/progression, and survival. This evidence concerns the gene MKI67 and neoplasm.