Construction of an M1 macrophage-related lncRNA signature for predicting the tumor immune microenvironment

Long noncoding RNAs (lncRNAs) are considered crucial molecules associated with the tumor microenvironment (TME) and tumor immune microenvironment (TIM). Macrophages are important members of the immune system, and M1 macrophage function-associated lncRNAs still need to be further investigated. In this study, a lncRNA signature was constructed based on transcriptome differences between high and low M1 macrophage infiltration cohorts. This lncRNA signature included seven lncRNAs: LINC01494, ZDHHC20-IT1, LINC01450, LINC00871, EVX1-AS, KIF25-AS and AADACL2-AS1, and all of them were upregulated in patients lacking M1 macrophages, indicating their roles in inhibiting macrophage infiltration and polarizing to the M1 subtype, leading to an immune exclusion TME, which has been demonstrated to be closely correlated with poor prognosis. This lncRNA signature not only predicted undesirable clinical outcomes but was also associated with the immunosuppressive environment of the tumor region, which is mediated by hindering antigen presentation and processing progress. In addition, the predictive value of this lncRNA signature for immune checkpoint inhibition (ICI) therapy was also evaluated, which further enriched and strengthened the power of lncRNAs in predicting the immunotherapy response rate.