ASCL1 and small cell lung carcinoma: We first evaluated the differential expression of transcripts previously reported to define distinct molecular subtypes of SCLC, including ASCL1 (SCLC-A), NEUROD1 (SCLC-N), POU2F3 (SCLC-P), and the SCLC-I subtype (defined as having low-level expression of these transcripts, with high YAP1) (Figure 1A, Supplementary Figure S2).