Using established gene expression markers of these SCLC cell states [16, 17], we found enrichment in GSK690‐sensitive cell lines in expression of epithelial genes, MYCL and EPCAM, and neuroendocrine genes, GRP, DDC, and ASCL1 (Fig. 2B,C and Fig. S5). The gene discussed is DDC; the disease is small cell lung carcinoma.