ASCL1 and small cell lung carcinoma: Herein, in accordance to the presence of major transcriptional factors, five phenotype subtypes of SCLC were investigated: SCLC-A (ASCL1), SCLC-N (NEUROD1), SCLC-P (POU2F3), SCLC-Y (YAP1), and SCLC-I (ASCL1-/NEUROD1-/POU2F3-) [33].