The Immune Response‐related Mutational Signatures and Driver Genes in Non‐small Cell Lung Cancer

: Immune checkpoint blockade (ICB) therapy has achieved remarkable clinical benefit in non-small-cell lung cancer (NSCLC), but our understanding of biomarkers that predict the response to ICB remain obscure. Here we integrated somatic mutational profile and clinicopathologic information from 113 NSCLC patients treated by ICB (CTLA-4/PD-1). High tumor mutation burden (TMB) and neoantigen burden were identified significantly associated with improved efficacy in NSCLC immunotherapy. Furthermore, we identified apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like (APOBEC) mutational signature was markedly associated with responding of ICB therapy (log-rank test, P = .001; odds ratio (OR), 0.18 [95% CI, 0.06-0.50], P < .001). The association with progression-free survival remained statistically significant after controlling for age, sex, histological type, smoking, PD-L1 expression, hypermutation, smoking signature and mismatch repair (MMR) (HR, 0.30 [95% CI, 0.12-0.75], P = .010). Combined high TMB with APOBEC signature preferably predict immunotherapy responders in NSCLC cohort. The CIBERSORT algorithm revealed that high APOBEC mutational activity samples were associated with increased infiltration of CD4 memory activated T cells, CD8+ T cells and natural killer (NK) cells, but reduced infiltration of regulatory T cells. Besides, individual genes mutation of IFNGR1 or VTCN1 were only found in responders; however, the PTEN mutation was only found in non-responders (Fisher's exact test, all P < .05). These findings may be applicable for guiding immunotherapy for patients with NSCLC.