NEUROD1 and small cell lung carcinoma: SCLC has recently been categorized into three subtypes with unique transcriptional characteristics and therapeutic vulnerabilities based upon differential expression of the transcription factors ASCL1 (SCLC-A; 51%), NEUROD1 (SCLC-N; 23%), and POU2F3 (SCLC-P; 7%) [6, 7], and a fourth subtype exhibits low expression of all three transcription factors with high inflammation and susceptibility to immune checkpoint inhibitors (SCLC-I; 17%) [6].