GRB10 as a pan-cancer biomarker linking oncogenic signaling, immunosuppression, and immunotherapy resistance

Growth Factor Receptor-Binding Protein 10 (GRB10) is an adaptor protein implicated in tyrosine kinase signaling, yet its pan-cancer role and clinical impact remain incompletely characterized. This study aims to define the pan-cancer landscape of GRB10 dysregulation and its clinical implications for prognosis and immunotherapy response. Multi-omics analysis of 33 TCGA cancers and validation in GEO cohorts assessed GRB10 expression, prognostic impact (Cox regression, Kaplan-Meier), functional enrichment (Gene Set Enrichment Analysis, Gene Set Variation Analysis), immune correlates (Spearman with immune genes, ESTIMATE/CIBERSORT/EPIC/TIMER/xCell infiltration), tumor mutational burden (TMB), and immunotherapy predictive power. In the TCGA pan-cancer cohort, GRB10 was significantly elevated in 11 cancer types (CHOL, COAD, ESCA, HNSC, KIRC, KIRP, LIHC, LUAD, LUSC, STAD, THCA) and downregulated in 4 (BLCA, BRCA, CESC, UCEC). Aberrant GRB10 expression was strongly associated with adverse prognosis in LGG, CESC, COAD, and LUAD for OS, DSS, and PFI, a finding validated externally in GEO colon cancer cohorts. Conversely, it served as a protective factor in KIRC. Functionally, GRB10 was implicated in epithelial-mesenchymal transition (EMT), evidenced by positive correlations with EMT pathway scores and key regulators (ZEB1, ZEB2, SNAI1, SNAI2). GRB10 expression robustly correlated with an immunosuppressive tumor microenvironment (TME), evidenced by negative enrichment of immune response pathways (e.g., IFN-α/γ) and complex associations with immune-related genes. Immune infiltration analysis revealed consistent positive correlations with CD4⁺ memory-resting T cells and negative correlations with CD4⁺ effector memory T cells across most cancers. Critically, high GRB10 expression predicted significantly shorter survival and poorer response rates in multiple immunotherapy-treated cohorts (urothelial carcinoma, melanoma, gastric cancer). GRB10 also showed significant associations with TMB in several cancers, and its protein interaction network was enriched in PI3K-Akt, FoxO, and Rap1 signaling pathways. Our pan-cancer analysis establishes GRB10 as a key facilitator of tumor progression, linked to EMT and an immunosuppressive microenvironment, and nominates it as a novel biomarker for adverse prognosis and resistance to immune checkpoint blockade therapy.