Supplementary methods and materials. Supplementary table S1: Gene signatures. Supplementary table S2: Sequences of primers for qRT-PCR and ChIP-PCR. Supplementary table S3: Sequences of siRNAs and shRNA. Supplementary table S4: Information of antibodies. Supplementary table S5: Univariate Cox regression analyses for overall survival and progression-free survival in the George’s cohort and GSE60052 cohort. Supplementary figure S1: Clustering CAF infiltration and evaluating the contribution of CAF to prognosis of SCLC. Supplementary figure S2: Association of CAFs with immune features in SCLC cohorts. Supplementary figure S3: Subtyping SCLC cases. Supplementary figure S4: Identification of NE and Non-NE cells and evaluation the effect of fibroblasts on proliferation of SCLC cells. Supplementary figure S5: Exploration of IL-6 and IL-6R in CAF-induced NE phenotypic reprogramming. Supplementary figure S6: Proliferation of SCLC cells upon treatment of siRNA or JAK inhibitor. Supplementary figure S7: Expression of MYC in SCLC cohorts.