Integrated analysis of single-cell and bulk RNA-sequencing identifies a signature based on B cell marker genes to predict prognosis and immunotherapy response in lung adenocarcinoma

As an essential component of the tumor microenvironment, B cells exist in all stages of tumor and exert important roles in anti-tumor immunity and shaping tumor development. We aimed to explore the expression profile of B cell marker genes and construct a prognostic signature based on these genes in Lung adenocarcinoma (LUAD). A total of 1268 LUAD patients from different cohorts were enrolled in this study. We performed an analysis of single-cell RNA-sequencing (scRNA-seq) data from Gene expression omnibus (GEO) database to identify B cell marker genes in LUAD. TCGA database was used to construct signature, and six cohorts from GEO database were used for validation. We also investigated the association between this signature and immunotherapy response. Based on 258 B cell marker genes identified by scRNA-seq analysis, a nine-gene signature was constructed for prognostic prediction in TCGA dataset, which classified patients into high-risk and low-risk groups according to overall survival. The multivariate analysis demonstrated that the signature was an independent prognostic factor. The signature's predictive power was verified in other six independent cohorts and different clinical subgroups. Analysis of immune profiles showed that high-risk groups presented discriminative immune-cell infiltrations and immune-suppressive states. More importantly, risk scores of the signature were closely correlated with PD-L1, tumor mutation burden, neoantigens, and tumor immune dysfunction and exclusion score. Our study proposed a novel prognostic signature based on B cell marker genes for LUAD patients. The signature could effectively indicate LUAD patients' survival and serve as a predictor for immunotherapy.