Molecular signatures of tumor progression in pancreatic adenocarcinoma identified by energy metabolism characteristics
Abstract Background: In this study, we aimed to describe a molecular evaluation of primary pancreatic adenocarcinoma (PAAD) based on comprehensive analysis of energy-metabolism-related gene (EMRG) expression profiles.Methods: Molecular subtypes were identified by non-negative matrix clustering algorithm clustering on 565 EMRGs. The overall survival (OS) predictive gene signature was developed, internally and externally validated based on three online PAAD datasets. Hub genes were identified in molecular subtypes by weighted gene correlation network analysis (WGCNA) co-expression algorithm analysis, and then enrolled for determination of prognostic genes. Univariate, LASSO and multivariate Cox regression analyses were performed to assess prognostic genes and construct the prognostic gene signature. Time-dependent receiver operating characteristic (ROC) curve, Kaplan-Meier curve and nomogram were used to assess the performance of the gene signature.Results: On the basis of EMRGs expression profile, we propose a molecular classification dividing PAAD into two subtypes: Cluster 1, which display more immune and stromal cell components in tumor microenvironment and higher tumor purity; and Cluster 2, which display worse OS. Moreover, by using a three-phase training, test and validation process, we construct a 4-gene signature that can constantly classify the prognostic risk of patients in all three datasets, and which present higher robustness and clinical usability compared with four previous reported prognostic gene signatures. In addition, a novel nomogram constructed by combining clinical features and the 4-gene signature showed confident clinical utility in PAAD. According to gene set enrichment analysis (GSEA), gene sets related to the high-risk group were participated in the neuroactive ligand receptor interaction pathway. Conclusions: In summary, the EMRG-based molecular subtypes and prognostic gene model provides a roadmap for patient stratification and trials of targeted therapies.