In-depth proteomic analysis identifies key gene signatures predicting therapeutic efficacy of anti-PD-1/PD-L1 monotherapy in non-small cell lung cancer.

Background: Immunotherapy has opened up a new era of individualized treatment for non-small cell lung cancer (NSCLC) with negative driver gene mutations. Anti-programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) antibodies have been the main options for immunotherapy over the past decade. Screening for predictive markers of anti-PD-1/PD-L1-responsive patients remains a focus in the field of immunotherapy, especially on the protein level in which relevant proteomic biomarkers are still lacking. Methods: We collected samples from 23 patients with NSCLC who received anti-PD-1/PD-L1 monotherapy and were followed up for three years. The proteomic profile of the tumor was obtained by mass spectrometry (MS). Meanwhile, we combined the RNA sequencing (RNA-seq) data of 27 patients treated with anti-PD-1/PD-L1 therapy in a previous study to establish an integrated gene network. Weighted correlation network analysis (WGCNA) and elastic network were implemented to screen the top gene modules for predicting treatment-responsive patients. Gene expression related mutational patterns were also retrieved for validation in the Memorial Sloan-Kettering Cancer Center (MSKCC) cohort. Results: Our results showed the gene expression profile of Conclusions: Our study indicated that key gene signatures identified by machine learning model could be utilized for clinical screening of patients who might benefit from anti-PD-1 therapy. Further mechanistic investigations around these genes are warranted.