A pan-cancer analysis revealed SKP2 as an inhibitor of the tumor immune microenvironment and a promising therapeutic target for immunotherapy.

BACKGROUND: S-Phase kinase associated protein 2 (SKP2) is a key regulator of the cell cycle and proliferation linked to cancer development. Our recent study has revealed that knocking out Skp2 in a mouse model significantly activates anti-tumor immunity. Although several studies have examined SKP2 in relation to the tumor immune microenvironment using public datasets, a comprehensive pan-cancer evaluation that integrates multi-omics layers and in vivo validation has remained limited. METHODS: In this study, we integrated multi-omics data from diverse public datasets to comprehensively analyze SKP2 expression characteristics and its relationship to tumor immunity across pan-cancer. A multiplex immunofluorescence assay was performed on tumors from Skp2 knockout and Skp2-intact mouse models for validation. RESULTS: Our findings indicate that SKP2 is overexpressed in various cancer types, leading to poor prognosis. Single-cell transcriptomic analyses further revealed that SKP2 is predominantly expressed in malignant and immune cells. Notably, a multiplex immunofluorescence assay on tumors from Skp2 knockout and Skp2-intact mouse models and pan-cancer data unveiled a correlation between SKP2 and the "immune-cold" microenvironment, which, possibly linked to the weakened antigen presentation, reduced secretion of chemokines in SKP2-overexpressing cancers. Additionally, we observed that SKP2 overexpression predicts worse immunotherapy efficacy. CONCLUSION: Our findings provide novel insights into the role of SKP2 in regulating the tumor immune microenvironment, suggesting targeting SKP2 as a promising strategy to enhance immunotherapy efficacy in pan-cancer settings.