ASCL1 and small cell lung carcinoma: Furthermore, we showed that, in subtypes defined by highest relative gene expression of the single transcription factors ASCL1, NEUROD1, POU2F3, and YAP1, per Rudin et al. [6], greatest numerical OS benefit with D + EP was observed in the SCLC-Y (YAP1) subtype, which is also associated with an inflamed phenotype and other markers of clinical benefit with immunotherapy [21, 22].