Genomic and TCR Repertoire Intratumor Heterogeneity of Small-cell Lung Cancer and its Impact on Survival

Abstract Small-cell lung cancer (SCLC) is speculated to harbor complex genomic intratumor heterogeneity (ITH) associated with high recurrence rate and suboptimal response to immunotherapy. Here, using multi-region whole exome/T cell receptor (TCR) sequencing as well as immunohistochemistry (IHC), we revealed a rather homogeneous mutational landscape but extremely cold and heterogeneous TCR repertoire in limited-stage SCLC (LS-SCLC) tumors. Compared to localized non-small cell lung cancers (NSCLCs), LS-SCLCs had similar predicted neoantigen burden and genomic ITH, but significantly colder and more heterogeneous TCR repertoire associated with higher chromosomal copy number aberration (CNA) burden. Higher mutational burden, higher T cell infiltration and positive PD-L1 expression were associated with longer overall survival (OS), while higher CNA burden were associated with shorter OS in patients with LS-SCLC.