Immune infiltration characteristics and prognostic significance of SERPINB7 in breast cancer

Objective To investigate the expression pattern of serine proteinase inhibitor B7 (SERPINB7) in breast cancer and its association with immune infiltration and patient prognosis.Methods Data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) were used to analyze differential SERPINB7 expression. Differentially expressed gene analysis, GO, KEGG, and GSEA were performed to explore related functions. Immune cell infiltration was assessed using single-sample GSEA (ssGSEA). Kaplan–Meier analysis and Cox regression models were applied to evaluate the prognostic value of SERPINB7, and a prognostic nomogram incorporating SERPINB7 was constructed.Results SERPINB7 was significantly upregulated in breast cancer tissues. Functional enrichment indicated its involvement in immune regulation, inflammatory responses, and cell differentiation. High SERPINB7 expression was positively associated with infiltration of macrophages, Th1 cells, and neutrophils, but negatively correlated with CD56bright natural killer cells, plasmacytoid dendritic cells (pDCs), and eosinophils. Survival analyses showed that high SERPINB7 expression predicted poorer overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI). Multivariate Cox analysis confirmed SERPINB7 as an independent unfavorable prognostic factor. The nomogram demonstrated improved predictive accuracy.Conclusion High SERPINB7 expression is closely associated with an immunosuppressive microenvironment and unfavorable prognosis in breast cancer, suggesting its potential as an immune-related prognostic biomarker.