NEUROD1 and cancer: To determine whether the inverse association between MAPK activity and NE differentiation is due to differences in cell of origin for the specific cancer types or instead attributed to the direct signaling pathways regulated by the mutated oncogenes, we conditionally expressed either EGFRL858R or KRASG12V, which are the most prevalent drivers in LUAD (Cancer Genome Atlas Research Network, 2014), as well as a GFP control in three SCLC cell lines; H2107 (ASCL1-high; SCLC-A Rudin et al., 2019), H82 (NEUROD1-high; SCLC-N Rudin et al., 2019), and H524 (SCLC-N).