ASCL1 and small cell lung carcinoma: In addition, we also performed immunohistochemistry (IHC) on formalin-fixed paraffin-embedded (FFPE) tissues from a large cohort of 90 SCLC patients (Supplementary Table S5), in which, the expression of ASCL1 and NEUROD1 were evaluated at the protein level (Supplementary Fig. S6g).