NEUROD1 and small cell lung carcinoma: Interestingly, there were two samples, MSK761 and MSK900b, that were assigned to ASCL1 or ASCL1/NEUROD1 groups by transcription factor expression, but which also clustered closer to POU2F3-driven PDXs by PCA and were notable for expression of YAP1 and its downstream genes such as LATS2 or CAV1. As mentioned earlier, the role of YAP1 as a defining subtype marker in SCLC has recently been questioned, and a new subtype defined by an inflamed gene signature was proposed12.