The main role of Ki-67 in pNET is to help distinguish carcinoid tumors (NETs) from large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung cancer (SCLC), especially in small biopsies with crush artefacts, where carcinoids can be mistaken for SCLC [16]. Here, MKI67 is linked to large cell neuroendocrine carcinoma.