Gene expression profile of EGFRwt/KRASwt/ALKwt lung adenocarcinoma (“pan-driver-gene-negative” LUAD) and developing a prognostic signature for “pan-driver-gene-negative” LUAD

For developing a accurate prognostic signature for “pan-driver-gene-negative” LUAD, we employed whole genome microarray expression profiling as a discovery platform to identify candidate genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis based on whole-genome microarrays indicated that the Wnt/β-catenin pathway was activated in “pan-driver-gene-negative” LUAD. Furthermore, the Wnt/β-catenin-pathway-based gene expression profiles revealed 39 transcripts differentially expressed by diagnostic status, with 30 genes being upregulated and 9 downregulated. Finally, a Wnt/β-catenin-pathway-based signature (CSDW) comprising 4 genes (β-catenin, Wnt2b, DVL3 and SOX9) was developed to classify patients into high-risk and low-risk groups in the training cohort. Patients with high-risk scores in the training cohort had shorter overall survival (hazard ratio [HR] 10·42, 6·46–16·79; p<0·001) than patients with low-risk scores. The CSDW performance was further validated in an internal cohort and two external cohorts. The protein expression levels of several hub genes, including β-catenin, SOX9, DVL3 and Wnt2b, were strongly correlated with lymphatic metastasis and distant organ metastasis. Furthermore, a nomogram comprising CSDW and other variables was generated to predict progression-free survival and overall survival in the training cohort and performed well in the three independent validation cohorts (C-index: 0·725, 0·697 and 0·693, respectively). For developing a accurate prognostic signature for “pan-driver-gene-negative” LUAD, we employed whole genome microarray expression profiling as a discovery platform to identify candidate genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis based on whole-genome microarrays indicated that the Wnt/β-catenin pathway was activated in “pan-driver-gene-negative” LUAD. Furthermore, the Wnt/β-catenin-pathway-based gene expression profiles revealed 39 transcripts differentially expressed by diagnostic status, with 30 genes being upregulated and 9 downregulated. Finally, a Wnt/β-catenin-pathway-based signature (CSDW) comprising 4 genes (β-catenin, Wnt2b, DVL3 and SOX9) was developed to classify patients into high-risk and low-risk groups in the training cohort. Patients with high-risk scores in the training cohort had shorter overall survival (hazard ratio [HR] 10·42, 6·46–16·79; p<0·001) than patients with low-risk scores. The CSDW performance was further validated in an internal cohort and two external cohorts. The protein expression levels of several hub genes, including β-catenin, SOX9, DVL3 and Wnt2b, were strongly correlated with lymphatic metastasis and distant organ metastasis. Furthermore, a nomogram comprising CSDW and other variables was generated to predict progression-free survival and overall survival in the training cohort and performed well in the three independent validation cohorts (C-index: 0·725, 0·697 and 0·693, respectively). In this multicenter analysis, we collected 626 “pan-driver-gene-negative” LUAD samples from three independent hospitals. In the discovery phase, we profiled the mRNA expression of each candidate gene using genome-wide microarrays in 52 paired LUAD and adjacent normal tissues. In the training phase, tissue microarrays (TMAs) and LASSO Cox regression analysis were applied to further screen candidate molecules in 189 patients (SYSUFH set). In the validation phase, one internal cohort (SYSUFH set, n=182) and two external cohorts (Sun Yat-sen University Cancer Center (SYSUCC) set, n=152; WUHAN set, n=103) were used to validate our novel prognostic signature.