Highlighting the heterogeneity of SCLC, genomic and transcriptomic profiling of mouse and human SCLC has revealed that SCLC comprises four distinct molecular subtypes (SCLC-A, SCLC-N, SCLC-P and SCLC-Y) characterised by the predominant expression of the ASCL1, NEUROD1, POU2F3 or YAP1 transcription factors (Ireland et al., 2020). The gene discussed is ASCL1; the disease is small cell lung carcinoma.