ASCL1 and small cell lung carcinoma: Mechanistically, co-expression of ASCL1 or NEUROD1 in a SCLC-N or SCLC-A cell line, respectively, caused transcriptional reprogramming with suppression of the cell fate defined by the endogenous TF and the alternative upregulation of gene expression programs driven by the ectopically expressed TF, accompanied by marked changes in the genome-wide chromatin accessibility.