In parallel, immunofluorescence further showed a lower cellular abundance of RNAPII in DMS‐53 SCLC cells, 4 h after lurbinectedin treatment (Mean ± SEM = −27.60 ± 1.514, t = 18.23, P < 0.0001, n = 3 biological replicates; Fig 4B and C), which was accompanied by a decrease in ASCL1, NEUROD1, leading to a failure in the transcription process (Fig 2A and B, green curves). Here, ASCL1 is linked to small cell lung carcinoma.