Identification of Genomic Instability Related Lncrna Signature Associated with Immune Microenvironment in Pancreatic Cancer

Background: Increasing evidence suggested that the critical roles for lncRNAs in the maintenance of genomic stability. However, the identification of genomic instability related lncRNA signature (GILncSig) and their clinical significance in tumor immune microenvironment of pancreatic cancer remain largely unexplored.Methods: In the present study, a systematic analysis of lncRNA expression profiles and somatic mutation profiles was performed in pancreatic cancer patients from TCGA. We performed co-expression network and Gene Ontology (GO) enrichment analyses to determine the potential functions and pathways involved in lncRNAs are associated with genomic instability. We then development a risk score model to describe the characteristics of the model and verify its prediction accuracy. ESTIMATE algorithm, single-sample gene set enrichment analysis (ssGSEA), and CIBERSORT analysis were employed to reveal the characteristics of tumor immune microenvironment in pancreatic cancer. The correlation of risk signature with immune infiltration and immune checkpoint blockade (ICB) therapy was analyzed. Results: We identified 206 GILncSig, of which five were screened to develop a prognostic GInLncSig model. Multivariate Cox regression analysis and stratified analysis revealed that the prognostic value of the GILncSig was independent of other clinical variables. ROC analysis suggested that GILncSig is better than the existing lncRNA-related signatures in predicting survival. Additionally, the prognostic performance of the GILncSig was also found to be favorable in patients carrying wild-type KRAS, TP53 and SMAD4. Besides, a nomogram exhibited appreciable reliability for clinical application in predicting the prognosis of patients. Finally, the risk score significantly correlated with immune score, immune-related signature, infiltrating immune cells (i.e. B cells, etc.), and ICB key molecules (i.e. CTLA4, etc.). Conclusion: In summary, the GILncSig identified by us may have crucial role in immune cell infiltration，immunotherapy and important indicator for clinical stratification management and therapy decisions for pancreatic cancer patients.