The prognostic value of immune infiltration signature and its potential mechanism in gastric cancer

The development of gastric cancer (GC) is closely associated with tumor microenvironment. Tumor infiltrating immune cells (TIICs), as a significant component of the tumor microenvironment, not only dominates the immune response of tumors, but is also valuable prognostic indicators. In our study, GC patients from GEO database and TCGA database were enrolled. The proportion of 22 kinds of TIICs were accurately evaluated by a deconvolution algorithm named CIBERSORT. The result showed TIICs component were varied in cancer tissue and adjacent tissue, besides the TIICs component had an effect on overall survival (OS). After LASSO cox regression and stepwise filter optimization analyzed, tumor tissues which were riches in M2 macrophages and activated mast cells, lack of plasma cells or activated CD4 memory T cells and neutrophils may cause a poor prognosis. Based on this result, a novel nomogram was stablished to assess the survival rate of GC patients. A survival immune risk (SIR) score model was further developed to validate the relationship between immune infiltration and pathological traits or oncogenic pathways in GC. In conclusion, this study may be contributed to finding new immunotherapy targets and providing individualize treatment strategies for GC patients.