RBL2 and small cell lung carcinoma: However, when tumors were initiated in the same RPR2 model specifically from pulmonary neuroendocrine cells (Ferone et al, 2020) that express the neuroendocrine marker CGRP (using Adeno‐CGRP‐Cre‐mediated deletion of Rb/p53/p130), the resulting metastatic SCLC did not upregulate NFIB (Yang et al, 2018).