Ki-67 antigen in lung carcinoids/neuroendocrine tumors: from a proliferation marker to a clinical compass.
INTRODUCTION Ki-67 has extensively been studied in lung neuroendocrine tumors (NETs), including typical and atypical carcinoid, yet it has never been formally accepted into classification. Its clinical application was limited to the differential diagnosis toward neuroendocrine carcinomas and the characterization of car...