A synthesis of recent studies of SCLC converged on four molecular subtypes—SCLC-A, SCLC-N, SCLC-P, and SCLC-Y, as featured by the differential expression of lineage transcription factors ASCL1, NEUROD1, POU2F3, and YAP1, respectively15. This evidence concerns the gene YAP1 and small cell lung carcinoma.